1999 DODGE RAM instrument panel

Governor pressure is monitored electronically and is used to
control transmission shifting. Electronic control system consists of
Powertrain Control Module (PCM), governor pressure solenoid, governor
pressure sensor, transmission fluid temperature sensor, OD (Overdrive)\
OFF switch, Throttle Position (TP) sensor and output shaft speed
sensor.
NOTE: Governor pressure sensor may also be referred to as governor
pressure transducer. Transmission fluid temperature sensor
may also be referred to as transmission fluid temperature
thermistor. Output shaft speed sensor may also be referred to
as transmission shaft speed sensor or shaft speed sensor.
Transmission shifting is controlled by throttle pressure and
governor pressure. Governor pressure is generated by electronic
components through control of line pressure. Transmission will not
upshift into 4th gear under the following conditions:
* 3rd gear upshift is not complete.
* OD OFF switch is in OFF position.
* Throttle is at 3/4 to WOT position.
* Vehicle speed is too low for 3-4 upshift.
* Transmission fluid temperature is less than 50
F (10C) or
greater than 250F (121C).
* Battery temperature is less than 5F (-15C).
OPERATION
POWERTRAIN CONTROL MODULE (PCM)
The PCM controls Torque Converter Clutch (TCC) operation,
overdrive clutch operation and the governor pressure solenoid. The PCM
determines shift points and TCC operation based on input signals
received from transmission fluid temperature sensor, output shaft
speed sensor, Crankshaft Position (CKP) sensor, Vehicle Speed Sensor
(VSS), Throttle Position (TP) sensor and battery temperature sensor.\
There are 4 governor pressure curves programmed into the PCM.
Governor pressure curves allow the PCM to adjust governor pressure for
varying conditions. One governor pressure curve is used for operation
when transmission fluid temperature is at or less than 30
F (1C). The
second governor pressure curve is used for operation when transmission
fluid temperature is at or greater than 30
F (1C) during normal city
operation or highway driving. The third governor pressure curve is
used for operation during wide open throttle (WOT). The fourth
governor pressure curve is used for operation when transfer case is in
low range.
The PCM controls TCC operation by operating the lock-up
solenoid located on the valve body. Lock-up solenoid may be referred
to as TCC solenoid. If OD switch is in the ON position, the TCC will
lock-up once transmission is in 4th gear with vehicle speed greater
than 45 MPH. If OD switch is in the OFF position, the TCC will lock-up
once transmission is in 3rd gear with vehicle speed greater than 35
MPH at light throttle application. When OD switch is in the OFF
position, the OD light on instrument panel will be illuminated.
The PCM prevents TCC operation and overdrive operation when
transmission fluid temperature is less than 50
F (10C). If
transmission fluid temperature exceeds 260F (126C), the PCM will
cause a 4-3 downshift and engage the TCC. The OD light will be
illuminated when the downshift occurs. Transmission will not upshift
until transmission fluid temperature decreases to approximately 230
F
(110F).

The OD (Overdrive) OFF switch is located on instrument panel,\
to the right of steering column. The OD OFF switch controls overdrive
operation by delivering an input signal to PCM. The PCM uses this
signal for controlling operation of overdrive solenoid on the valve
body.
When overdrive switch is in the OFF position, OD light on
instrument panel will be illuminated and transmission will not upshift
into 4th gear for overdrive operation. When OD switch is in the ON
position, OD light on instrument panel will not be illuminated and
transmission will upshift into 4th gear for overdrive operation.
If OD switch is in the ON position, the TCC will lock-up when
transmission is in 4th gear with vehicle speed greater than 45 MPH. If
overdrive switch is in the OFF position, the TCC will lock-up when
transmission is in 3rd gear with vehicle speed greater than 35 MPH at
light throttle application.
THROTTLE POSITION (TP) SENSOR
The TP sensor delivers an input signal to the PCM to indicate
throttle position. The PCM uses this input signal for controlling TCC
operation, governor pressure and upshift into 4th gear for overdrive
operation.
TRANSMISSION FLUID TEMPERATURE SENSOR
NOTE: Transmission fluid temperature sensor may also be referred to
as transmission fluid temperature thermistor or transmission
fluid temperature sender.
Transmission fluid temperature sensor delivers an input
signal to the PCM to indicate transmission fluid temperature. The PCM
uses this input signal for controlling the TCC, overdrive operation
and governor pressure. Transmission fluid temperature sensor is
located on the valve body and is integral with governor pressure
sensor. See Fig. 1.
OUTPUT SHAFT SPEED SENSOR
NOTE: Output shaft speed sensor may also be referred to as
transmission shaft speed sensor or shaft speed sensor.
Output shaft speed sensor is located on overdrive unit
attached to rear of transmission. Output shaft speed sensor is mounted
above the lugs on park gear in the overdrive unit. Speed sensor input
signals are generated when lugs on park gear rotate past face of
sensor. Input signals are delivered to PCM. The PCM uses this input
signal for controlling transmission operation. The Vehicle Speed
Sensor (VSS) also serves as a back-up to the output shaft speed
sensor. The VSS signal is also an input to the PCM.
TROUBLE SHOOTING
* PLEASE READ THIS FIRST *
NOTE: For symptom trouble shooting, see appropriate AUTOMATIC
TRANSMISSION OVERHAUL article.
PRELIMINARY INSPECTION
Visually inspect all electrical wiring, looking for chafed,

Box (DRB) scan tool with appropriate cartridge for system
diagnosis. Other after-market scan tools may be used for
system diagnosis. The following procedure is for DRB scan
tool usage. Use scan tool manufacturer's instruction for
operating scan tool.
NOTE: Ensure battery is fully charged before proceeding with test.
1) Ensure ignition is off. Connect DRB to Data Link Connector
(DLC) located under driver's side of instrument panel. Using scan
tool, display all Diagnostic Trouble Codes (DTCs). Identify DTCs once
retrieved. See DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES table.
2) If scan tool will not power up, check for loose cable
connections or faulty cable. If cable connections and cable are okay,
check voltage at DLC terminal No. 16. Voltage should be at least 11
volts. If voltage is not as specified, check wiring circuit and
necessary fuses. See WIRING DIAGRAMS.
3) If scan tool displays an error message, RAM TEST FAILURE,
CARTRIDGE ERROR, KEY PAD TEST FAILURE, or LOW OR HIGH BATTERY, this
indicates a scan tool failure.
4) If DTCs are displayed, perform appropriate test(s). See
DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES table. If no DTCs are
displayed, see TROUBLE SHOOTING in appropriate AUTOMATIC TRANSMISSION
OVERHAUL article.
DIAGNOSTIC TROUBLE CODES (DTC) & DRB MESSAGES









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DTC DRB-III Scan Tool Message
P0711 .................. TRANS TEMP SENSOR, NO TEMP RISE AFTER START
P0712 ............................. TRANS TEMP SENSOR VOLTAGE TO LOW
P0713 ............................ TRANS TEMP SENSOR VOLTAGE TO HIGH
P0720 ..................... LOW OUTPUT SPEED SENSOR RPM ABOVE 15 MPH
P0740 .................... TORQ CONVERTER CLU, NO RPM DROP AT LOCKUP
P0743 ........ TORQUE CONVERTER CLUTCH SOLENOID/TRANS RELAY CIRCUITS
P0748 ........... GOVERNOR PRESSURE SOL CONTROL/TRANS RELAY CIRCUITS
P0751 ....................... OD SWITCH PRESSED (LO) MORE THAN 5 MIN\
P0753 ................ TRANS 3-4 SHIFT SOLENOID/TRANS RELAY CIRCUITS
P0783 ....................... 3-4 SHIFT SOL, NO RPM DROP @ 3-4 SHIFT
P1740 (1) .......................... TCC OR O/D SOLENOID PERFORMANCE
P1756 .................... GOV PRESS NOT EQUAL TO TARGET @ 15-20 PSI
P1757 ...................... GOV PRES ABOVE 3 PSI IN GEAR WITH 0 MPH
P1762 .................... GOV PRESS SEN OFFSET VOLTS TO LOW OR HIGH
P1763 ....................... GOVERNOR PRESSURE SENSOR VOLTS TO HIGH
P1763B ...................... GOVERNOR PRESSURE SENSOR VOLTS TO HIGH
P1764 ........................ GOVERNOR PRESSURE SENSOR VOLTS TO LOW
P1765 ..................... TRANS 12 VOLT SUPPLY RELAY CNTRL CIRCUIT
P1899 .......................... P/N SWITCH STUCK IN PARK OR ON GEAR
( 1) - BR body only.









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CLEARING DIAGNOSTIC TROUBLE CODES
After repairs have been performed, clear DTCs from PCM memory
using scan tool, following scan tool manufacturer's instructions.
NOTE: If malfunction is no longer present after DTC is stored in
PCM memory, the PCM will erase DTC after ignition has been
cycled at least 50 times. DTC may be cleared by using scan
tool. Follow scan tool manufacturer's instructions. DTCs may
also be cleared by disconnecting negative battery cable for a
period of time, but other vehicle control modules may also be

13) On A/T models, ensure all electrical connectors are clean
and properly connected to electrical plugs on transmission case. On
all models, check for loose or defective electrical connections on
starter and starter solenoid.
MECHANICAL INSPECTION
Compression
Manufacturer does not provide information for checking
compression.
FUEL SYSTEM
AIR IN FUEL SYSTEM
NOTE: Air in the fuel system may cause hard starting, rough
running, excessive smoke, poor engine performance, engine
misfire, poor fuel economy and fuel knock. Air may enter fuel
system whenever fuel supply lines, fuel filter/water
separator, fuel injection pump, fuel injectors or high
-pressure fuel lines are removed or disconnected.
1) Inspect all low-pressure fuel lines from fuel tank to fuel
transfer pump, fuel heater and fuel filter/water separator for signs
of leakage. Inspect all high-pressure fuel lines for signs of leakage.
See FUEL INJECTOR & HIGH-PRESSURE FUEL LINES under FUEL SYSTEM.
2) After repairing fuel leak, bleed air from fuel system. See
FUEL LINE BLEEDING under FUEL SYSTEM in REMOVAL, OVERHAUL &
INSTALLATION - TRUCKS - DIESEL article.
FUEL HEATER
1) Fuel heater is located in fuel filter/water separator. See
Fig. 1 . Fuel heater uses a fuel heater temperature sensor for
controlling operation of the fuel heater.
2) A defective fuel heater may cause excessive wax build-up
in the fuel filter/water separator during cold ambient temperatures.
Wax build-up may cause hard starting, prevent engine from
accelerating, low power, Blue smoke or White smoke. For testing of
fuel heater and fuel heater temperature sensor, see SYSTEM & COMPONENT
TESTING - TRUCKS - DIESEL article.
FUEL HEATER RELAY
Ensure fuel heater relay, located in power distribution
center is installed correctly and that terminals are not corroded. For
fuel heater relay testing, see SYSTEM & COMPONENT TESTING - TRUCKS -
DIESEL article.
FUEL FILTER/WATER SEPARATOR
NOTE: A blocked or restricted fuel filter/water separator may cause
starting problems, prevent engine from accelerating, low
power or White smoke. If an excessive amount of water
collects in filter/separator in a short period of time, it
may be necessary to drain and clean fuel tank.
1) When ignition switch is first turned to ON position,
WATER-IN-FUEL (WIF) warning light should come on for 2 seconds to
perform bulb and wiring circuit test and then go off. WATER-IN-FUEL
(WIF) warning light is located on instrument panel, just below the

* ONE GAUGE NOT OPERATING PROPERLY
OVERHEAD CONSOLE CONCERNS
* AVERAGE MPH/FUEL ECON INOPERATIVE OR WRONG (CMTC FAILS TO
RESPOND TO INSTRUMENT CLUSTER DIMMING, DISTANCE TO EMPTY
INOPERATIVE OR WRONG, ELAPSED TIME INOPERATIVE/WRONG, SWITCH
ON CMTC INOPERATIVE, TRIP ODOMETER INOPERATIVE/WRONG)
* CMTC DISPLAY SHOWS FAILED
* CMTC SEGMENTS FAIL TO LIGHT UP
* INCORRECT READING BEYOND +/- 5
* REPAIRING "OC" IN CMTC DISPLAY
* REPAIRING "SC" IN CMTC DISPLAY
POWER DOOR LOCK SYSTEM
* DOOR LOCK SWITCH FAILURE (PDL)
* DOOR UNLOCK SWITCH FAILURE (PDL)
* AUTOMATIC (ROLLING) DOOR LOCKS INOPERATIVE
* DOORS LOCK WITH KEY IN IGNITION & LEFT DOOR OPEN
* ONE OR ALL DOORS FAILING TO LOCK FROM ONE SWITCH (ONE OR ALL
DOORS FAILING TO UNLOCK FROM ONE SWITCH)
* REMOTE KEYLESS ENTRY PROBLEM
VEHICLE THEFT/SECURITY SYSTEM
* DOOR DISARM SWITCH FAILURE
* DOOR LOCK SWITCH FAILURE
* DOOR UNLOCK SWITCH FAILURE
* EEPROM CHECKSUM FAILURE
* INTERNAL ROM TEST FAILURE
* IDENTIFYING VTSS PROBLEMS
WINDSHIELD WIPER SYSTEM
* WIPER PARK SWITCH FAILURE
* INTERMITTENT WIPERS INOPERATIVE
* NO WIPER ACTUATION AFTER WASH BUTTON PUSHED
* WIPER SPEED SENSITIVE FEATURE INOPERATIVE
CHIME SYSTEM
CHIME INOPERATIVE WITH EXTREME COOLANT TEMPERATURE
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting any module connector.
1) Using scan tool, actuate chime. If chime sounds, go to
next step. If chime does not sound, replace Central Timer Module
(CTM). CTM is located under left side of instrument panel.
2) Using scan tool, read Powertrain Control Module (PCM)
DTCs. If no engine coolant temperature related codes exist, go to next
step. If engine coolant temperature related codes exist, see
appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE section.
3) Due to difficult access of coolant temperature sensor, Oil
Pressure Switch (OPS) will be used to verify CCD bus message from PCM.\
Disconnect OPS connector. OPS is located near bottom of distributor.

Connect a jumper wire between OPS connector terminals. Start engine
and allow to idle for 20 seconds. Increase engine speed to 1600 RPM.
If chime sounds, system is currently functioning properly. If chime
does not sound, go to next step.
4) Remove instrument cluster. See appropriate INSTRUMENT
PANELS article. Disconnect Instrument cluster 10-pin Gray connector
"B". Connect a jumper wire between ground and Dark Blue/Red wire of
instrument cluster 10-pin Gray connector terminal No. 7. Turn ignition
on. If chime sounds, replace instrument cluster. If chime does not
sound, repair open Dark Blue/Red wire.
CHIME INOPERATIVE - KEY IN IGNITION & LF DOOR OPEN
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting any module connector.
1) Turn ignition off. Open driver's door. If chime does not
sound, go to next step. If chime sounds, system is currently
functioning correctly.
2) Using scan tool, read driver's door ajar switch status. If
scan tool displays LFDOOR AJAR SWITCH: CLOSED, go to next step. If
scan tool does not display LFDOOR AJAR SWITCH: CLOSED, go to OPEN LEFT
DOOR AJAR CIRCUIT.
3) Using scan tool, read key-in ignition chime state. If scan
tool does not display KEY-IN IGNITION CHIME STATE: ON, go to next
step. If scan tool displays KEY-IN IGNITION CHIME STATE: ON, replace
Central Timer Module (CTM). CTM is located under left side of
instrument panel.
4) Disconnect key-in ignition switch connector. See Fig. 1.
Connect jumper wire between key-in ignition switch connector Light
Blue wire and ground. Using scan tool, read key-in ignition chime
state. If scan tool does not display KEY-IN IGNITION CHIME STATE: ON,
go to next step. If scan tool displays KEY-IN IGNITION CHIME STATE:
ON, replace ignition switch. See appropriate STEERING COLUMN SWITCHES
article.
Fig. 1: Identifying Steering Column Harness Connector Locations
Courtesy of Chrysler Corp.
5) Access CTM 14-pin Green connector C1. Remove connector
cover. Do not disconnect connector. Connect a backprobe jumper wire

between terminal No. 9 (Light Blue wire) and chassis ground. Using
scan tool, read key-in ignition switch status. If scan tool does not
display KEY-IN IGNITION CHIME STATE: ON, replace CTM. If scan tool
displays KEY-IN IGNITION CHIME STATE: ON, repair open Light Blue wire
between CTM and ignition switch.
CHIME INOPERATIVE AT ALL TIMES
NOTE: Perform VERIFICATION TEST VER-1A after each repair.
Turn ignition on. Using scan tool, select BODY SYSTEM, BODY
COMPUTER then ACTUATORS. Actuate chime. If chime sounds, system is
currently functioning correctly. If chime does not sound, replace
Central Timer Module (CTM). CTM is located under left side of
instrument panel.
CHIME INOPERATIVE WITH EXTERIOR LIGHTS ON
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting any module connector.
1) Remove ignition key. Using scan tool, read key-in ignition
chime state. If scan tool does not display KEY-IN IGNITION CHIME
STATE:
OFF, go to step 4). If scan tool displays KEY-IN IGNITION CHIME STATE:
OFF, go to next step.
2) Open driver's door. Using scan tool, read door ajar
status. If scan tool displays LFDOOR AJAR SWITCH: CLOSED, go to next
step. If scan tool does not display LFDOOR AJAR SWITCH: CLOSED, go to
OPEN LEFT DOOR AJAR CIRCUIT.
3) Turn on headlights. If chime does not sound, repair open
headlight sense circuit (Light Blue wire) between CTM and headlight
switch. See appropriate wiring diagram in BODY CONTROL COMPUTER -
INTRODUCTION article. If chime sounds, system is currently functioning
correctly.
4) Open driver's door. Using scan tool, read door ajar
status. If scan tool displays LFDOOR AJAR SWITCH: CLOSED, go to next
step. If scan tool does not display LFDOOR AJAR SWITCH: CLOSED, go to
OPEN LEFT DOOR AJAR CIRCUIT.
5) Disconnect key-in ignition switch connector. See Fig. 1.
Using scan tool, read key-in ignition chime state. If scan tool
displays KEY-IN IGNITION CHIME STATE: ON, go to next step. If scan
tool does not display KEY-IN IGNITION CHIME STATE: ON, replace
ignition switch. See appropriate STEERING COLUMN SWITCHES article.
6) Turn ignition off. Disconnect Central Timer Module (CTM).\
CTM is located under left side of instrument panel. Remove ignition
key. Ensure all lights and accessories are off. Close all doors. Using
external ohmmeter, measure resistance between ground and terminal No.
9 (Light Blue wire) on CTM Green connector "A". If resistance is less
than 10 ohms, repair Light Blue wire between CTM and ignition switch
for short to ground. If resistance is 10 ohms or more, replace CTM.
CHIME INOPERATIVE WITH LOW OIL PRESSURE
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to

disconnecting any module connector.
1) Disconnect Oil Pressure Switch (OPS). OPS is located near\
bottom of distributor. Connect a jumper wire between OPS connector
terminals. Start engine and allow to idle for 20 seconds. Increase
engine speed to 1600 RPM. If chime sounds, go to next step. If chime
does not sound, go to step 3).
2) Turn ignition on. Using scan tool, actuate chime. If chime
does not sound, replace Central Timer Module (CTM). CTM is located
under left side of instrument panel. If chime sounds, system is
currently functioning properly.
3) Using scan tool, access CLUSTER MONITOR. With engine
running, read CCD oil pressure. If scan tool reading does not match
instrument cluster reading, replace instrument cluster. If scan tool
reading matches instrument cluster reading, go to next step.
4) Remove jumper wire. Connect a jumper wire between ground
and OPS connector Gray wire. Start engine and allow to idle for 20
seconds. Increase engine speed to 1600 RPM. If chime sounds, repair
open ground circuit between OPS connector and ground. If chime does
not sound, go to next step.
5) Turn ignition on. Using scan tool, actuate chime. If chime
does not sound, replace Central Timer Module (CTM). CTM is located
under left side of instrument panel. If chime sounds, go to next step.
6) Remove instrument cluster. See appropriate INSTRUMENT
PANELS article. Disconnect CTM 14-pin Green connector C1. Using an
external ohmmeter, measure resistance of Dark Blue/Red wire between
CTM 14-pin Green connector C1 terminal No. 2 and instrument cluster
10-pin connector C2 terminal No. 7. If resistance is less than 5 ohms,
replace CTM. If resistance is 5 ohms or more, repair open Dark
Blue/Red wire.
CHIME SOUNDS WITH DRIVER DOOR OPEN
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting any module connector.
1) Ensure all interior and exterior lights are off. Remove
ignition key and open driver's door. If chime does not sound, system
is currently functioning correctly. If chime sounds, go to next step.
2) Using scan tool, read key-in ignition chime state. If scan
tool displays KEY-IN IGNITION CHIME STATE: "ON/OFF", go to next step.
If scan tool does not display KEY-IN IGNITION CHIME STATE: "ON/OFF",
replace Central Timer Module (CTM). CTM is located under left side of
instrument panel.
3) Disconnect key-in ignition switch connector. See Fig. 1.
Using scan tool, read key-in ignition chime state. If scan tool
displays KEY-IN IGNITION CHIME STATE: ON, go to next step. If scan
tool does not display KEY-IN IGNITION CHIME STATE: ON, replace
ignition switch. See appropriate STEERING COLUMN SWITCHES article.
4) Turn ignition off. Disconnect Central Timer Module (CTM).\
CTM is located under left side of instrument panel. Remove ignition
key. Ensure all lights and accessories are off. Close all doors. Using
external ohmmeter, measure resistance between ground and terminal No.
9 (Light Blue wire) on CTM Green connector "A". If resistance is less
than 10 ohms, repair Light Blue wire between CTM and ignition switch
for short to ground. If resistance is 10 ohms or more, replace CTM.
DOOR AJAR SYSTEM