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
\
\
\
\
\
\
\
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.
\
\
\
\
\
\
\
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
* PLEASE READ THIS FIRST *
NOTE: For engine-related DTCs, see appropriate SELF-DIAGNOSTICS
article in ENGINE PERFORMANCE. Engine performance DTCs must
be repaired first, as engine performance and related
component signals will affect transmission operation and
diagnosis.
All references to Using scan tool, perform TCC SYSTEM TEST
are for scan tool driven testing of TCC system. Follow manufactures
scan tool instructions.
All connector references in the following testing apply to
harness connectors unless otherwise specified. For circuit, wire color
and connector terminal identification, see CONNECTOR IDENTIFICATION
and WIRING DIAGRAMS. After all repairs are complete or any component
is replaced, perform verification test as follows:
* DTC P0751 perform appropriate verification VER-2A.
* All DTCs except P0751 perform appropriate verification
VER-5A.
DTC P0711: TRANS TEMP SENSOR, NO TEMP RISE AFTER START
NOTE: To test transmission temperature sensor, engine and
transmission temperature must be less than 85F (29C).
1) Using scan tool, read DTCs. If DTCs P0712, P0713 or P1899
are present, repair these DTCs before proceeding. If neither of these
DTCs are present, go to next step.
2) Using scan tool, read and record Engine Coolant
Temperature (ECT) sensor temperature, and transmission temperature
sensor temperature. If transmission temperature is within 9
F (-13C)
of ECT temperature, go to step 5). If transmission temperature is not
within 9
F (-13C) of ECT temperature, go to next step.
3) Start engine and let it idle in gear, with brake on.
Monitor transmission temperature sensor. If transmission temperature
does not increase steadily 15
F (-9C) over a 10 minute period, go to
step 5). If transmission temperature increases steadily 15F (-9C)
over a 10 minute period, go to next step.
4) Inspect all related wiring and connectors. Repair as
necessary. If wiring and connectors are okay, see INACTIVE DTC
CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
5) Disconnect transmission solenoid harness connector.
Inspect connector and terminals for damage. Repair as necessary. If
connector and terminals are okay, replace transmission governor
pressure/temperature sensor.
DTC P0712: TRANS TEMP SENSOR VOLTAGE TOO LOW
Circuit Description
Circuit is monitored continuously while key is on, and engine
running. Code sets if transmission temperature sensor voltage is less
than 1.55 volts for 2.2 seconds.
Possible Causes
* Transmission temperature sensor wiring harness defective.
* Transmission pressure/temperature sensor defective.
* Transmission temperature signal circuit short to ground.
* Transmission temperature signal circuit short to sensor
ground circuit.
* PCM defective.
Diagnostic Procedures
1) On AN and DN bodies, go to next step. On all except AN and
DN bodies, record freeze frame data. Use scan tool to read DTCs. If
DTC SPECIFIC GOOD TRIPS counter is not displayed or displayed count is
not "0", go to step 11). If DTC SPECIFIC GOOD TRIPS counter is
displayed and displayed count is "0", go to next step.
2) Turn ignition off. Disconnect PCM harness connectors.
Inspect connectors and terminals for damage. Repair as necessary. If
connectors and terminals are okay, measure resistance between
transmission temperature signal circuit at White PCM harness connector
C2 and ground circuit at Black PCM harness connector C1. If resistance
is less than 550 ohms, go to step 8). If resistance is 550 ohms or
more, go to next step.
3) If resistance is 550-2300 ohms, go to next step. If
resistance is greater than 2300 ohms, go to DTC P0713: TRANS TEMP
SENSOR VOLTAGE TOO HIGH.
4) Measure resistance of transmission temperature signal
circuit between ground and White PCM harness connector C2. If
resistance is 5 ohms or less, go to step 8). If resistance is greater
than 5 ohms, go to next step.
5) Reconnect all harness connectors. Using scan tool, read
TRANS TEMP voltage. If voltage is less than 1.5 volts, replace PCM. If
voltage is 1.5 volts or greater, go to step 7). On all other bodies,
go to next step.
6) Conditions required to set DTC P0712 are not present at
this time. DTC P0712 sets when transmission temperature sensor voltage
at PCM is less than 1.55 volts for 2.2 seconds. Possible causes are:
shorted transmission temperature sensor wiring, faulty connections,
faulty transmission temperature sensor or faulty PCM. Go to next step.
7) Inspect all related wiring and connectors. Repair as
necessary. If wiring and connectors are okay, see INACTIVE DTC
CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
8) Disconnect transmission solenoid harness connector.
Inspect connector and terminals for damage. Repair as necessary. If
connector and terminals are okay, measure resistance between
transmission temperature signal circuit at White PCM harness connector
C2 and sensor ground circuit at Black PCM harness connector C1. If
resistance is less than 5 ohms, repair transmission temperature signal
circuit for short to ground circuit. If resistance is 5 ohms or
greater, go to next step.
9) Measure resistance between ground and transmission
temperature signal circuit at White PCM harness connector C2. If
resistance is less than 5 ohms, repair transmission temperature signal
circuit for short to ground. If resistance is 5 ohms or greater, go to
next step.
10) Reconnect transmission solenoid harness connector. Remove
transmission oil pan. Disconnect transmission pressure/temperature
sensor harness connector. Measure resistance between transmission
temperature signal circuit at White PCM harness connector C2 and
sensor ground circuit at Black PCM harness connector C1. If resistance
is less than 5 ohms, repair or replace transmission solenoid and
harness assembly. If resistance is 5 ohms or greater, go to next step.
11) Measure resistance between ground and transmission
temperature signal circuit at White PCM harness connector C2. If
resistance is less than 5 ohms, repair or replace transmission
solenoid and harness assembly. If resistance is 5 ohms or greater,
replace transmission pressure/temperature sensor.
DTC P0713: TRANS TEMP SENSOR VOLTAGE TOO HIGH
Circuit Description
Circuit is monitored continuously while key is on, and engine
between Black PCM harness connector C1 and transmission
pressure/temperature sensor harness connector. If resistance is
greater than 5 ohms, repair or replace transmission solenoid and
harness assembly. If resistance is 5 ohms or less, replace
transmission pressure/temperature sensor.
10) Reconnect all harness connectors. Using scan tool, read
TRANS TEMP voltage. If voltage is greater than 3.76 volts, replace
PCM. If voltage is 3.76 volts or less, conditions required to set DTC
P0713 are not present at this time. DTC P0713 sets when transmission
temperature sensor voltage at PCM is greater than 3.76 volts for 2.2
seconds. Possible causes are: open transmission temperature sensor
wiring, faulty connections, faulty transmission temperature sensor or
faulty PCM. Go to next step.
11) Inspect all related wiring and connectors. Repair as
necessary. If wiring and connectors are okay, see INACTIVE DTC
CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
DTC P0720: LOW OUTPUT SPEED SENSOR RPM ABOVE 15 MPH (EXCEPT
BR BODY)
Circuit Description
Circuit is monitored continuously while key is on, and gear
selector is not in Park or Neutral. Code sets if vehicle speed is
above 15 MPH and output shaft speed is below 60 RPM for 2.6 seconds as
measured from vehicle speed sensor.
Possible Causes
* Open output speed sensor ground circuit.
* Damaged ignition wiring.
* Open output speed sensor signal circuit.
* Short to ground in output speed sensor signal circuit.
* Park/Neutral switch code present.
* Malfunctioning sensor.
* Short to ground in output speed sensor ground circuit.
* Malfunctioning PCM.
* OSS harness intermittent defective.
Diagnostic Procedure
1) Using scan tool, check SPECIFIC GOOD TRIPS counter. If DTC
SPECIFIC GOOD TRIPS counter is not displayed or displayed count is not
"0", go to step 12). If DTC SPECIFIC GOOD TRIPS counter is displayed
and displayed count is "0", go to next step.
2) Record all DTCs and one trip failures. If DTC P1899 is
present, repair P/N switch code first. See DTC P1899: P/N SWITCH STUCK
IN PARK OR ON GEAR. If DTC P1899 is not present, go to next step.
3) Raise and support vehicle. Using scan tool, erase DTCs.
See CLEARING DIAGNOSTIC TROUBLE CODES. Start engine. Place engine in
1st gear. Using scan tool, read output speed sensor. Release brake and
let wheels roll, keeping speed below 15 MPH. If scan tool shows 60 RPM
or less, go to step 6). If scan tool shows greater than 60 RPM, go to
next step.
4) While monitoring output speed sensor, wiggle harness
between output speed sensor and PCM. If reading dropped towards zero
while wiggling harness, repair intermittent short or open in harness.
If reading does not drop towards zero while wiggling harness, go to
next step.
5) Using scan tool, erase DTCs. See CLEARING DIAGNOSTIC
TROUBLE CODES. Road test vehicle. If code returns, there are no other
potential causes. Replace PCM. If code does not return, testing is
complete.
6) Turn ignition off. Disconnect PCM and output speed sensor
harness connectors and inspect for damage. Repair as necessary. If no
problem is found, measure resistance between output speed sensor
terminals. If resistance is 300-1200 ohms, go to next step. If
resistance is not as specified, replace output speed sensor.
7) Reconnect output speed sensor. Measure resistance between
ground and output speed sensor ground circuit at PCM harness
connector. If resistance is greater than 5 ohms, go to next step. If
resistance is not as specified, repair output speed sensor ground
circuit for a short to ground.
8) Measure resistance between ground and output speed sensor
signal circuit at PCM harness connector. If resistance is less than 5
ohms, repair output speed sensor signal circuit for a short to ground.
If resistance is not as specified, go to next step.
9) Measure resistance between output speed sensor signal
circuit and ground circuit at PCM harness connector. If resistance is
300-1200 ohms, replace PCM. If resistance is not as specified, go to
next step.
10) Disconnect output speed sensor harness connector. Measure
resistance of output speed sensor signal circuit between output speed
sensor harness connector and PCM harness connector. If resistance is
greater than 5 ohms, repair open in output speed sensor signal
circuit. If resistance is not as specified, repair open in output
speed sensor ground circuit.
11) Turn ignition on. Measure voltage between ground and
speed sensor ground circuit at PCM harness connector. Place gearshift
lever in each gear position and record voltage at each position. If
voltage is greater than one volt in any gear position, repair speed
sensor ground circuit for a short to power. If voltage is not as
specified, go to next step.
12) Raise and support vehicle. Start engine. Place gearshift
lever in "OD" position. Release brakes and allow wheels to rotate.
Using scan tool, monitor output speed sensor. While monitoring output
speed sensor, wiggle harness between output speed sensor and PCM. If
reading dropped towards zero while wiggling harness, repair
intermittent short or open in harness. If reading does not drop
towards zero while wiggling harness, problem is intermittent. See
INACTIVE DTC CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is
complete.
DTC P0740: TORQ CONV CLU, NO RPM DROP AT LOCKUP
Circuit Description
Circuit is monitored continuously while key is on, and gear
selector is not in Park or Neutral. Code sets if Torque Converter
Clutch (TCC) does not achieve desired drop in RPM when TCC solenoid is\
near maximum duty cycle. A bad test 3 consecutive times is required to
set code.
Possible Causes
* Misfire trouble code set.
* Vehicle stalls (faulty TCC solenoid).
* TCC shaft seal/seal defective.
* Transmission fluid contaminated.
* TCC solenoid wiring harness defective.
* TCC defective.
* TCC hydraulic circuit damaged.
Diagnostic Procedure
1) Using scan tool, read DTCs. On all bodies except AB and WJ
bodies, go to next step. On AB and WJ bodies, if DTC SPECIFIC GOOD
TRIPS counter is not displayed or displayed count is not "0", go to
step 10). If DTC SPECIFIC GOOD TRIPS counter is displayed and
displayed count is "0", indicating DTC still exists, go to next step.