Transmission Effects and possible causes:
Scenario 1)- All PRNDL lights stay illuminated
indefinitely in Park following a Key start.
> Wrong Part Number TCM for application
> TRS connector not plugged in
> C1 through C4 (T1, T3, T41, or T42) circuits are
either open, shorted to ground, or shorted to 12
volts.
> PCI bus failure (Open or shorted resulting in no
communication to BCM or Cluster)
> TRS
> TCM
> BCM
Scenario 2)-9P9is indicated following a key start
but all PRNDL lights illuminate in9N9following a
shift from9R9to9N9. If PRNDL lights illuminate in
9N9and shifter is moved directly into939or9L9
position without pausing in9OD9, then the9OD9
position shift schedule and electronic display will
indicate9OD9until the shifter is shifted into the
9OD9position and held for at least 3 seconds.
> Worn Manual Lever (Rooster Comb). Check for
heavy wearing by TRS switch contacts
> Intermittent C1 through C4 (T1, T3, T41 or T42)
circuits. Check for corrosion, terminal push-outs
or spread terminals at 60-way and/or TRS switch
10-way connector
> TRS
> TCM
> BCM
Scenario 3)- If the invalid code happened while
operating in the939or9L9position, then the939or
9L9shift schedule and electronic display will be
frozen (regardless of whether9OD9,939or9L9is
selected) until the shifter is moved to the9N9
position (all PRNDL lights will illuminate) and
then back to the9OD9position and held there for at
least 3 seconds in order to resume the normal9OD9
shift schedule and electronic display.
> Intermittent C1 through C4 (T1, T3, T41 or T42)
circuits. Check for corrosion, terminal push-outs
or spread terminals at 60-way and/or TRS con-
nector
> TRS
> TCM
> BCM
These same symptoms may occur without the
code P0705(28) getting set. It is possible that the
invalid code that was sensed by the TCM only
occurred once or twice during the given ignition key
start and/or did not last for longer than 0.1 second.Name of code:P0120(29) - Throttle Position Sen-
sor Signal
When monitored:Whenever the engine is run-
ning.
Set condition:This code is set if the throttle angle
goes out of range or if throttle angle changes
abruptly (ie: faster than the throttle body motion
could occur)
Theory of operation:The Transmission Control
Module (TCM) receives the throttle position signal
from the Throttle Position Sensor (TPS) through a
wire spliced into the TPS circuit to the PCM. The
TPS has a 5-volt pull up supplied from the Power-
train Control Module (PCM). The signal is checked
for out-of-range as well as an intermittent (exces-
sive signal changes).
Transmission Effects:Extremely erratic trans-
mission shifting with an intermittent TPS signal
just prior to setting the code. If the intermittent
does not last long enough to set the code, the
customer will say that the transmission violently
hunts between gears. The TCM will use a calcu-
lated throttle angle supplied by the PCM over the
PCI bus. If the PCI bus is unavailable, the TCM will
use a default throttle angle of 24 degrees for the key
start in which the code was set. The TCM will try to
use the TPS signal again on the next key start.
Possible causes:
> Open or shorted TPS signal and/or ground cir-
cuits
> TCM connector problems
> TPS or TPS connector (Check PCM DTC's)
> PCM
> TCM
Name of code:P1787(31) - OD Hydraulic Pressure
Test Failure
P1788(32) - 2-4 Hydraulic Pressure Test Failure
P1789(33) - OD/2-4 Hydraulic Pressure Test Failure
When monitored:In 1st, 2nd, or 3rd gear with
engine speed above 1000 RPM shortly after a shift
and every minute thereafter.
Set condition:Immediately after a shift into 1st,
2nd, or 3rd gear, with engine speed above 1000
RPM, the TCM momentarily turns on element
pressure to the 2-4 and/or OD clutch circuits to
identify that the appropriate pressure switch
closes. If the pressure switch does not close it is
tested again. If the switch does not close the second
time, the appropriate code is set.
Theory of operation:The Transmission Control
Module (TCM) tests the OD and 2-4 pressure
switches when they are off (OD and 2-4 are tested in
1st gear, OD in 2nd gear, and 2-4 in 3rd gear). The
test verifies that the switches are operational. The
TCM verifies that the switch closes when the cor-
9
GENERAL INFORMATION
the L-R pressure switch does not indicate pressure.
A second detection of L-R pressure results in setting
the code.
Transmission Effects:At speeds above 72 Km/h
(45 MPH), EMCC is inhibited. Once speed falls
below 72 Km/h (45 MPH), the transmission will go
into relay open limp-in mode and the MIL will
illuminate.
Possible causes:
> Valve body - Solenoid valve stuck in L-R position
> Intermittent short to ground or open circuit in
L-R Pressure Switch Sense circuit (with code 24
only)
> Solenoid pack (with code P1784(24) only)
> TCM (with code P1784(24) only)
Name of Code:P1793(48) - Torque Reduction
(TRD) Link Communication Error
Note: The MIL may set on some engines (3.3L, 3.8L,
3.5L)
When Monitored:Whenever the engine is run-
ning
Set condition:This code is set when the TCM
sends multiple torque reduction messages to the
PCM and the TCM does not receive a response from
the PCM.
Theory of Operation:During high torque shifts
the TCM will send a message requesting that the
PCM reduce engine power until the shift is com-
pleted. This message is sent from the TCM to the
Powertrain Control Module across the Torque Man-
agement Request Sense Circuit. The PCM will
acknowledge the TCM request by sending a mes-
sage across the PCI bus within a specific amount of
time. The TRD Link communication is also tested
periodically for operation whenever the engine is
running and the vehicle is not moving with zero
degrees throttle.
Transmission Effects:Maximum throttle angle
used by TCM will be 54 degrees. As a result a
customer my complain about loss of performance or
of short shifting when driving aggressively.
Possible Causes:
> Sticky Throttle Position Sensor (TPS)
> Wiring or Connector problems in the Torque
Management Request Sense Circuit
> PCM
> TCM
Name of code:P0736(50) - Gear Ratio Error in
Reverse
P0731(51) - Gear Ratio Error in 1st
P0732(52) - Gear Ratio Error in 2nd
P0733(53) - Gear Ratio Error in 3rd
P0734(54) - Gear Ratio Error in 4th
P0715(56) - Input Speed Sensor Error
P0720(57) - Output Speed Sensor Error
P1794(58) - Speed Sensor Ground Error
When monitored:The transmission gear ratio is
monitored continuously while the transmission is in
gear.
Set condition:This code is set if the gear ratio is
not correct for a period of time.
± Codes 50 through 54 sets if the ratio of the
input RPM (Nt) to the output RPM (No) does
not match the given gear ratio.
± Code 56 sets if there is an excessive change in
input RPM in any gear
± Code 57 sets if there is an excessive change in
output RPM in any gear
± Code 58 sets after a TCM reset in neutral and
Nt/No equals a ratio of input to output of 2.50
A hard code sets within 3 seconds, an intermit-
tent code sets within 15 seconds.
Theory of operation:The transmission system
uses two speed sensors, one to measure input RPM
and one to measure output RPM. These inputs are
essential for proper transmission operation. There-
fore, the integrity of this data is verified through
the following checks:
1. When in gear, if the gear ratio does not compare
to a known gear ratio, the corresponding in-gear
trouble code is set (codes 50 through 54).
2. An excessive change in input or output speeds
indicating signal intermittent will result in
codes 56 and/or 57 being set.
3. After a TCM reset in neutral, observing erratic
output and input speed sensor signals indicates
a loss of the common speed sensors ground. This
sets a code 58.
Transmission Effects:The transmission will not
go into relay open limp-in mode until three gear
ratio error events occur in a given key start. This
allows for intermittent problems to correct them-
selves without opening the relay. However, if a gear
ratio error develops, a code is always set, but if the
condition corrects itself the transmission will con-
tinue without requiring the ignition key to be cycled
on and off. Many different events could occur given
the range of failures possible for codes 50 through
58. The following are a few examples:
± Codes 51, 52, 53, 54, 56, and 57 at speeds
above 72 Km/h (45 MPH) - The appropriate
code is set, EMCC is aborted and current gear
is maintained. If while still traveling above 72
Km/h (45 MPH), the gear ratio becomes valid
again, EMCC will reengage and normal oper-
ation will resume. If the gear ratio becomes
intermittent and recovers three times in a
given key start, the current gear will be main-
tained and EMCC inhibited, then the trans-
mission will go into relay open limp-in mode if
12
GENERAL INFORMATION
throttle is applied below 72 Km/h (45 MPH) or
at 35 Km/h (22 MPH) with closed throttle.
± Codes 51, 52, 53, 54, 56, and 57 (at speeds
between 35 and 72 Km/h (22 and 45 MPH) - If
one of these codes is set between 35 and 72
Km/h (22 and 45 MPH), the current gear will
be maintained until the gear ratio problem
corrects itself. If throttle is applied, the trans
will go to 2nd gear. If this happens and the
gear ratio problem goes away, normal opera-
tion will resume. If three gear ratio problems
are identified in a given key start, the current
gear will be frozen until throttle is applied.
The transmission will then go into relay open
limp-in mode with throttle applied at speeds
between 35 and 72 Km/h (22 and 45 MPH).
± Codes 51, 52, 53, 54, 56, and 57 (at speeds
below 35 Km/h (22 MPH) - If a gear ratio
problem is identified below 35 Km/h (22 MPH),
the transmission will immediately substitute
second gear for the current gear. If the gear
ratio problem goes away, normal operation will
resume. If three gear ratio problems are iden-
tified in a given key start, the transmission
will go into relay open limp-in mode.
Possible causes:
Code P0736(50) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Valve body - #1 ball check or LR switch valve
sticking - may also set code P0731(51)
> Speed sensor or associated wiring
± may also set codes P0731(51), P0715(56), or
P0720(57)
> Failed or slipping LR clutch - may also set code
P0731(51)
> LR seal leakage (Intermittent no drive or re-
verse)
> Sticky LR accumulator seals (Intermittent no
drive or reverse)
> Failed reverse clutch (hard code)
± OD/Rev lip seal leakage
± Worn reaction shaft support seal rings
± Snap ring out of position
Code P0731(51) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Valve body - #1 ball check or LR switch valve
sticking - may also set code P0736(56) or have no
Reverse
> Speed sensor or associated wiring - may also set
codes P0736(50), P0715(56), or P0720(57)> Failed or intermittent slipping UD clutch - may
also set P0732(52), or P0733(53)
± UD seal leakage (intermittent)
± Worn input clutch hub bushing (hard code at
heavy throttle)
± Sticky UD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
± Solenoid pack (UD pressure in 4th gear)
> Failed or slipping LR clutch - may also set code
P0736(56) or have no Reverse
± LR seal leakage (Intermittent)
± Sticky LR accumulator seals (Intermittent)
Code P0732(52) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Failed or slipping 2-4 clutch - may also set code
P0734(54)
± 2-4 seal leakage (intermittent)
± Sticky accumulator seals (intermittent)
> Failed or intermittent slipping UD clutch - may
also set code P0731(51) and/or P0733(53)
± UD seal leakage (intermittent)
± Worn input clutch hub bushing (hard code at
heavy throttle)
± Sticky UD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
± Solenoid pack (UD pressure in 4th gear)
Code P0733(53) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Failed or slipping OD clutch - may also set code
P0734(54)
± OD and Reverse inner and outer lip seal leak-
age (usually hard code)
± Sticky OD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
± Broken OD/UD tapered snap ring - (hard code
at heavy throttle)
> Failed or intermittent slipping UD clutch - may
also set code P0731(51) and/or P0732(52)
± UD seal leakage (intermittent)
± Worn input clutch hub bushing (hard code at
heavy throttle)
± Sticky UD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
13
GENERAL INFORMATION
± Solenoid pack (UD pressure in 4th gear)
Code P0734(54) - Excludes geartrain failures which
should be obvious upon disassembly
> If code P1791(35) is also set, follow diagnostic
procedure for code P1791(35) first
> Failed or slipping OD clutch - may also set code
P0733(53)
± OD and Reverse inner and outer lip seal leak-
age (usually hard code)
± Sticky OD accumulator seals (intermittent)
± Worn reaction shaft support seal rings (hard
code at heavy throttle)
± Broken OD/UD tapered snap ring - (hard code
at heavy throttle)
> Failed or slipping 2-4 clutch - may also set code
P0732(52)
± 2-4 seal leakage (intermittent)
± Sticky accumulator seals (intermittent)
Codes P0715(56) and P0720(57)
> Failed input or output speed sensor (intermittent
or hard code)
> Shorted or open wiring between TCM and speed
sensor(s) (intermittent)
> Connector problems at 60 TCM connector and/or
speed sensor connector
Code P1794(58)
> Open or shorted speed sensor ground (speed
sensor ground is different from chassis ground)
> Open or shorted Temperature Sensor wiring to
TRS
> TRS - Will also set code P1799(74)
> TCM
Name of code:P1796(70) - Autostick Sensor Cir-
cuit (If equipped)
Note: RS is a MUXED Autostick system
When monitored:Whenever the engine is run-
ning.
Set condition:
1) The transmission shift lever is not in AutoStick
and either the upshift or downshift switch is closed.
2) Upshift and downshift switches closed at the
same time.
Theory of operation:In the AutoStick Mode
(manual shift mode), upshifts and downshifts are
actuated manually. Shift requests are detected by
monitoring the MUXED upshift and downshift
switches. The Transmission Control Module (TCM)
monitors the above set conditions. A set condition
will be tolerated for up to 15 seconds before setting
a code.Transmission Effects:The OD position shift
schedule is substituted while operating in the au-
tostick gear selector position. No limp-in mode
occurs.
Possible causes:
> Wiring or connector problems
> AutoStick switch failure
> TCM
Name of code:P1797(71)- Manual Shift Overheat
When monitored:Whenever the engine is run-
ning.
Set condition:1) If the engine temperature ex-
ceeds 124C (255 ÉF) while operating in AutoStick
mode.
2) If the transmission temperature exceeds 135C
(275 ÉF) while in AutoStick mode
Theory of operation:Transmission and engine
temperatures are monitored during vehicle opera-
tion. If conditions occur causing the engine or
transmission to overheat, the AutoStick mode will
be canceled, and a code will be set.
Transmission Effects:The 3 position shift sched-
ule that is used in non-AutoStick applications is
substituted while operating in the AutoStick gear
selector position. No limp-in mode occurs.
Possible causes:
> Engine overheat - refer to service manual for
diagnosis and repair
> Transmission Overheat
± Restricted transmission cooling system
± Transmission fluid overfilled
± Radiator fan not functioning properly
± Extended driving in low gear
Note:Strenuous driving conditions may cause the
vehicle to overheat. If the driver operates in or
initiates AutoStick with an overheated vehicle, the
code will be set.
Name of code:P1798 (73) - Deteriorated Transaxle
Fluid
When monitored:At every Fully Electronically
Modulated Converter Clutch (FEMCC) to Partial
Electronically Modulated Converter Clutch (PEM-
CC) transition miles when A/C compressor clutch is
being cycled.
Set condition:The code will be set if vehicle
shudder is detected 20 times when the A/C clutch is
cycled.
Theory of operation:While in 3rd or 4th gear
FEMCC and just before the A/C clutch engages, the
Powertrain Control Module (PCM) requests the
Transmission Control Module (TCM) to momen-
tarily establish PEMCC operation. If vehicle shud-
der is detected during the FEMCC to PEMCC
transition, a counter is incremented. If the count
reaches 20, the trouble code is set. The driver may
14
GENERAL INFORMATION
then notice harsh bumps when the A/C clutch is
being cycled, but vehicle shudder will be elimi-
nated. After 35 OBDII (EURO STAGE III OBD)
warm-up starts or if the code is cleared, PEMCC
will be reactivated to see if shudder is still present.
If one shudder event occurs, the code will be reset.
Clearing the code and running battery disconnect
with the DRBIIItis the only way to reset the
shudder counter from 20 back to zero.
Transmission Effects:This code does not cause
the transmission to go into limp-in mode. However,
once the code is set, FEMCC to PEMCC operation
before the A/C clutch engagement will be disabled
for 35 OBDII (EURO STAGE III OBD) warm up
starts.
Possible causes:
> Degraded transmission fluid
> Wheels severely out of alignment
> Internal torque converter problem
Name of Code:P1799(74) - Calculated Oil Temper-
ature in Use
When Monitored:When ever the Engine is run-
ning.
Set condition:The code is set if any of the follow-
ing conditions exist for three consecutive key starts:
> The Temperature Sensor voltage is out of range
(below 0.07 volts or greater than 4.94 volts)
> If continuous erratic Temperature Sensor voltage
is sensed.
> The Temperature Sensor temperature stays be-
low 27C (80ÉF) for an extended period of time.
Theory of Operation:The TCM uses a Tempera-
ture Sensor to monitor the transmission sump tem-
perature. This temperature is used to determine
which shift schedule the TCM is to use. (See Trans-
mission Operation and Shift Scheduling at Various
Sump Temperatures in this diagnostic manual) If
the Temperature Sensor circuit fails to operate
properly the TCM will use the calculated oil tem-
perature routine found in prior model year TCM. If
this occurs for three consecutive key starts, the code
will be set. The TCM will then test the Temperature
Sensor circuit after every 35 OBDII (EURO STAGE
III OBD) warm-up starts. If the Temperature Sen-
sor circuit is OK, the Temperature Sensor data is
used in place of the Calculated Oil Temperature
data.
Transmission Effects:If the Temperature Sensor
indicates a temperature below -18C (0É F) or above
115C (240É F) at start up, The TCM compares the
calculated oil temperature to the indicated Temper-
ature Sensor oil temperature. If the calculated oil
temperature differs significantly from the Temper-
ature Sensor value, the calculated oil temperature
will be used for that key start.Possible Causes:
> Wiring or Connector problems in the transmis-
sion temperature sensor signal circuit.
> TRS
> TCM
Name of Code:P1738(75) - High Temperature
Operation Activated.
When Monitored:Whenever the engine is running.
Set Condition:Immediately once the Overheat
Shift Schedule is activated.
Theory of Operation:If the transmission oil tem-
perature rises above 115C (240ÉF), the overheat
shift schedule is activated refer to Transmission
Operation as a function of Transmission Oil Tem-
perature and the code is set. The DTC is an infor-
mation code only and is being set to aid the techni-
cian in determining root cause of a customer
driveability issue. The code is also intended to alert
the technician to determine if a cooling system
malfunction has occurred or if an additional trans-
mission air to oil cooler should be added to the
vehicle if the customer regularly drives in a manner
that overheats the transmission. Extended opera-
tion above 115C (240ÉF) will reduce the durability of
the transmission and should be avoided. Correcting
the cooling system malfunction or installing an
additional transmission oil cooler will improve
transmission durability especially for customers
who operate in city/construction stop and go traffic,
tow trailers regularly, drive aggressively in low gear
or drive regularly in mountainous areas.
Transmission Effects:Information only code. -
Overheat shift schedule was activated, no limp-in
condition occurs. 2nd gear partial EMCC above 40
Km/h (25 MPH), 3rd gear EMCC from 45-69 Km/h
(28-43 MPH), delayed 3-4 upshift at 69 Km/h (43
MPH), early 4-3 coastdown at 66 Km/h (41 MPH),
EMCC operation under all conditions above 40
Km/h (25 MPH) except at closed throttle or 1st gear.
Possible Causes:
± Transmission Overfilled with Oil
± Engine cooling fan failure
± Engine thermostat stuck closed
± Radiator corroded or packed with dirt
± Transmission Oil Cooler Plugged
± Customer driving pattern requires additional
transmission cooling
Name Of Code:P1739(76) - Power-Up at Speed
When Monitored:When TCM (transmission con-
trol module) initially powers-up.
Set Condition:If the TCM powers up while in the
9Drive9position and the vehicle is going above 32
Km/h (20 MPH), the code is set.
Theory of Operation:If a vehicle loses power to
the TCM, the vehicle will go to the 2nd gear mode
15
GENERAL INFORMATION
> Quick Learn should generally not be used as a
repair procedure unless directed by a repair or
diagnostic procedure. If the transmission system
is exhibiting a problem that you think is caused
by an invalid CVI, you should try to relearn the
value by performing the appropriate driving ma-
neuver. In most cases, if a quick learn makes a
vehicle shift better, the vehicle will return with
the same problem.
> Before performing Quick Learn, it is imperative
that the vehicle be shifted into OD with the
engine running and the oil level set to the correct
level. This step will purge air from the clutch
circuits to prevent erroneous clutch volume val-
ues which could cause poor initial shift quality.
> If an unused TCM is installed on a vehicle with a
HOT engine, Quick Learn will cause the TCM to
report a cold calculated oil temperature. This
requires monitoring the calculated oil tempera-
ture using the DRBIIIt. If the temperature is
below 15C (60É F), the transmission must be run
at idle or driven in gear until it goes above 15C
(60ÉF). If the temperature is above 93C (200ÉF),
the transmission must cool to below 93C (200ÉF).
> First gear is engaged in overdrive after Quick
Learn is completed. Place the vehicle in park
after performing Quick Learn.
The Quick Learn function should be performed:
± Upon installation of a new service TCM
± After replacement or rebuild of internal trans-
mission components or the torque converter
± If one or more of the clutch volumes indexes
(CVI's) contain skewed readings because of
abnormal conditions.
To perform the Quick Learn procedure, the fol-
lowing conditions must be met.
± It is imperative that the vehicle be shifted into
OD with the engine running and the oil level
set to the correct level. This step will purge the
air in the clutch circuits to prevent erroneous
clutch volume values, which could cause poor
initial shift quality.
± The brakes must be applied.
± The engine must be idling.
± The throttle angle (TP sensor) must be less
than 3 degrees.
± The shift lever position must stay in neutral
until prompted to shift into OD.
± The shift lever must stay in OD after the9Shift
to Overdrive9prompt until the DRBIIItindi-
cates the procedure is complete.
± The oil temperature must be between 15C
(60ÉF) and 93C (200ÉF).NOTE:The above conditions must be maintained
during the procedure to keep the procedure from
being aborted.
The Quick Learn procedure is performed with the
DRBIIItby selecting9Transmission9system then
9Miscellaneous9functions, then9Quick Learn9. Follow
the procedure instructions displayed on the DRBIIIt.
3.3.9 CLUTCH VOLUMES
The L-R clutch volume is updated when doing a
2-1 or 3-1 coast down shift. The transmission tem-
perature must be between 21-49C (70-120É F). The
clutch volume should be between 35 and 83.
The 2-4 clutch volume is updated when doing a
1-2 shift. The transmission temperature must be
above 43C (110ÉF). The clutch volume should be
between 20 and 77.
The OD clutch volume is updated when doing a
2-3 shift. The transmission temperature must be
above 43C (110ÉF). The clutch volume should be
between 40 and 150.
The UD clutch volume is updated when doing a
4-3 or 4-2 shift. The transmission temperature must
be above 43C (110ÉF). The clutch volume should be
between 24 and 70.
3.3.10 ELECTRONIC PINION FACTOR
The transmission output speed signal supplies
distance pulses to the powertrain control module
(PCM), which are used to calculate speed and
mileage. A pinion factor is stored in the transmis-
sion control module (TCM) in order to provide the
appropriate distance pulses for the vehicle. The
pinion factor is programmed into the TCM at the
assembly plant.
Using the following steps, the pinion factor can be
checked and/or reset using the DRBIIIt:
1. Select Transmission system, then Miscellaneous
functions, then Pinion Factor. The DRBIIItwill
display the current tire size.
2. If the tire size is incorrect, depress the Enter key
and then select the correct size.
3. Depress the Page Back key to exit the reset
procedure.
Notes About Electronic Pinion Factor Features
The nature of the electronic pinion factor requires that
certain features must be taken into consideration.
> If no pinion factor is stored in an installed TCM,
the vehicle speedometer will not operate, engine
speed will be limited to 2300 RPM, and catalyst
damage may occur.
> Selecting a wrong tire size will cause the speed-
ometer to be inaccurate and will also cause any
speed related features to operate improperly.
Note: After replacing the TCM, you must
reprogram pinion factor
17
GENERAL INFORMATION
4.3 WARNINGS
4.3.1 VEHICLE DAMAGE WARNINGS
Before disconnecting any control module, make
sure the ignition is ªoffº. Failure to do so could
damage the module.
When testing voltage or continuity at any control
module, use the terminal side (not the wire end) of
the connector. Do not probe a wire through the
insulation; this will damage it and eventually cause
it to fail because of corrosion.
Be careful when performing electrical tests so as
to prevent accidental shorting of terminals. Such
mistakes can damage fuses or components. Also, a
second code could be set, making diagnosis of the
original problem more difficult.
4.3.2 ROAD TEST COMPLAINT VEHICLE
Some complaints will require a test drive as part
of the repair verification procedure. The purpose of
the test drive is to try to duplicate the diagnostic
code or symptom condition.
CAUTION: BEFORE ROAD TESTING A
VEHICLE, BE SURE THAT ALL
COMPONENTS ARE REASSEMBLED.
DURING THE TEST DRIVE, DO NOT TRY TO
READ THE DRBIIITSCREEN WHILE IN
MOTION. DO NOT HANG THE DRBIIITFROM
THE REAR VIEW MIRROR OR OPERATE IT
YOURSELF. HAVE AN ASSISTANT
AVAILABLE TO OPERATE THE DRBIIIT.
Road testing is an essential step in the diagnostic
process that must not be overlooked. Along with
diagnostic information obtained from the DRBIIIt
Scan Tool and the original customer concern, the
road test helps to verify the problem and observe
operation under actual vehicle driving conditions.
Just as important as the road test is, there are
preliminary inspections that should be carried out
prior to the road test. Always check the fluid level
and condition before going on a road test or per-
forming other tests. Also try to determine the type
of fluid being used. Improper fluid can result in
problems. Additionally, a variety of complaints can
be caused by incorrect fluid level. Some of the
conditions caused by incorrect fluid level are as
follows:
²Delayed engagement
²Poor shifting or erratic shifts
²Excessive noise
²Overheating
The next step is to verify that the shift linkage is
correctly adjusted. If the gearshift linkage is incor-rectly adjusted because of wear or incorrect adjust-
ment, a number of complaints can result.
The TCM monitors the Shift Lever Position (SLP)
Sensor at all times. If the linkage is incorrectly
adjusted, the TCM may sense a shift lever position
that is not correct for the gear range chosen by the
driver. This may cause diagnostic trouble codes to
be set and a possible limp-in situation.
The following complaints may also be the result
of an incorrectly adjusted or worn linkage.
²Delayed clutch engagement or erratic shifts
²Vehicle able to drive in Neutral
²Engine not able to crank in Park or Neutral
²Gearshift linkage able to be shifted without the
key in the ignition
²Not able to remove the ignition key in Reverse
²Parking pawl not engaging
The shift linkage should also be adjusted when
replacing the transaxle, repairing the valve body or
repairing any component between the shift lever
and the transaxle.
Some questions to ask yourself when considering
the road test are listed below:
²Is the complaint or concern what you think it is,
based the driver 's description of the problem?
²Is the transaxle operating normally, or is there a
real problem?
²When does the malfunction occur?
²Is the problem in only one gear range?
²What temperature does the complaint occur?
²Is the transaxle in limp-in mode?
4.3.3 ELECTRONIC PINION FACTOR
WARNINGS
The pinion factor must be set for all new trans-
mission control modules. If the pinion factor is not
set or if it is set incorrectly, any speedometer, speed
control, rolling door locks, and other devices that
are operated by the powertrain and body controllers
will not function properly.
4.3.4 BULLETINS AND RECALLS
The service procedures contained in this manual
are correct. provided that all applicable Safety
Recalls and Technical Service Bulletins have been
performed.
5.0 REQUIRED TOOLS AND
EQUIPMENT
> DRBIIIt(diagnostic read-out box) - Must be at
latest release level.
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GENERAL INFORMATION
> Transmission Simulator (Miller # 8333)
> Transmission Simulator (Miller # 8333-1)
Adapter harness kit and panel overlay for FWD
vehicles.
> Jumper wires
> Test Light (minimum of 25 ohms of resistance)
> Ohmmeter
> Voltmeter
> Pressure gauge (0-300 PSI)
6.0 GLOSSARY OF TERMS
6.1 ACRONYMS
BCMBody Control Module
CKTCircuit
CVIClutch Volume Index
DLCData Link Connector
DRBIIItDiagnostic Readout Box
DTCDiagnostic Trouble Code
EATXElectronic Automatic Transaxle
EMCCElectronically Modulated Converter
Clutch
FCMFront Control Module (part of the
IPM system)
IODIgnition off-draw
IPMIntelligent Power Module
IRTIntelligent Recovery Timer
ISSInput Speed Sensor
LEDLight Emitting Diode
LRLow/reverse Clutch or Pressure
Switch
LULockupMICMechanical Instrument Cluster
MILMalfunction Indicator Lamp
OBDIIOn Board Diagnostics
ODOverdrive Clutch or Pressure
Switch
OSSOutput Speed Sensor
PCMPowertrain Control Module
PEMCCPartial Electronically Modulated
Converter Clutch
PLUPartial Lockup
REVReverse Clutch
SLPKSolenoid Pack
SSVSolenoid Switch Valve
SWSwitch
TCCTorque Converter Clutch
TCMTransmission Control Module
TPThrottle Position
TRDTorque Reduction
TRSTransmission Range Sensor
UDUnderdrive Clutch
2-42nd and 4th gear Clutch or Pres-
sure Switch
6.2 DEFINITIONS
OBDII (EURO STAGE III OBD) Trip - A vehicle
start and drive cycle such that all once per trip
diagnostic monitors have run.
Key Start - A vehicle start and run cycle of at least
20 seconds.
Warm-up Cycle - A vehicle start and run cycle
such that the engine coolant must rise to at least
71C (160ÉF) and must rise by at least 4.4C (40ÉF)
from initial start up. To count as a warm-up cycle,
no DTC may occur during the cycle.
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GENERAL INFORMATION