complete.
16) Repair or replace transmission solenoid and harness
assembly. Reconnect all disconnected harness connectors. Using scan
tool, perform GOV and 3-4 SHIFT VALVE SYSTEM TEST. Select 1st gear and
read governor pressure voltage. If voltage is one volt or greater,
replace PCM. If voltage is less than one volt, test is complete.
17) Remove transmission control relay. Inspect transmission
control relay connector and terminals for damage. Repair as necessary.
If connector and terminals are okay, turn ignition on. Measure voltage
between ground and fused B+ circuit at transmission control relay
connector. If voltage is 10 volts or less, repair open fused B+
circuit. If voltage is greater than 10 volts, go to next step.
18) Turn ignition off. Measure resistance of transmission
control relay output circuit at transmission control relay connector
and TCC solenoid harness connector. If resistance is greater than 5
ohms, repair open transmission control relay output circuit. If
resistance is 5 ohms or less, go to next step.
19) Measure resistance between ground and transmission
control relay output circuit at transmission solenoid harness
connector. If resistance is less than 5 ohms, repair short to ground
in transmission control relay output circuit. If resistance is 5 ohms
or greater, replace transmission control relay.
20) Using scan tool, erase DTCs. Start engine. Using scan
tool, read DTCs while wiggling wiring harness between governor
pressure solenoid and PCM. Note if DTC P0748 resets. If DTC P0748
resets, repair wiring harness as necessary. If DTC P0748 does not
reset, go to next step.
21) 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 P0751: O/D SWITCH PRESSED (LO) MORE THAN 5 MIN
Circuit Description
Circuit is monitored after engine is running for 10 seconds
and reviewed every 440ms. Code sets if overdrive switch is held low
for 5 minutes or more from time of closure or ignition on.
Possible Causes
* Fused B+ circuit open.
* Solenoid and harness assembly defective.
* Governor pressure solenoid out of tolerance.
* Transmission control relay defective.
* Governor pressure solenoid control circuit shorted to
ground.
* Governor pressure solenoid harness defective.
* Governor pressure solenoid control circuit open.
* Transmission control relay output circuit open.
* Transmission control relay output circuit shorted to
ground.
* PCM defective.
Diagnostic Procedure
1) 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 ground
and Overdrive (O/D) off switch sense circuit at Gray PCM harness
connector C3. If resistance is less than 5 ohms, go to next step. If
resistance is 5 ohms or greater, go to step 3).
2) Disconnect O/D switch harness connector. Inspect connector
and terminals for damage. Repair as necessary. If connector and
terminals are okay, measure resistance between ground and O/D off
switch sense circuit at O/D switch harness connector. If resistance is
less than 5 ohms, repair short to ground in O/D switch sense circuit.
If resistance is 5 ohms or greater, replace O/D off switch.
3) Conditions required to set DTC P0751 are not present at
this time. DTC P0751 sets if PCM senses O/D off switch input is held
low for 5 minutes or from time of closure or ignition on. Possible
causes are: faulty O/D OFF switch, shorted wire or faulty PCM. 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 P0753: TRANS 3-4 SHIFT SOLENOID/TRANS RELAY CIRCUITS
Circuit Description
Circuit is monitored continuously while key is on. Code sets
if voltage detected on 3-4 shift solenoid control circuit at the
Powertrain Control Module (PCM) does not match expected voltage.
Possible Causes
* Transmission mechanically defective.
* TPS codes set.
* Transmission 3-4 solenoid wiring harness defective.
* Transmission fluid burnt or oil pan has excessive debris.
* Shift control solenoid circuit shorted to ground.
* Solenoid and harness assembly defective.
* Transmission control relay output circuit open.
* Transmission control relay output circuit shorted to
ground.
* PCM defective.
Diagnostic Procedure (AN & DN Bodies)
1) If DTC P1765 is also set, go to DTC P1765: TRANS 12-VOLT
SUPPLY RELAY CNTRL CIRCUIT. If DTC P1765 is not set, go to next step.
2) Road test vehicle and reach a speed of 50 MPH. Depress
Overdrive (OD) switch 4 times so vehicle attempts to shift from 4th
gear to 3rd gear and back. If vehicle does not shift between 3rd and
4th gear, go to step 5). If vehicle shifts between 3rd and 4th gear,
go to next step.
3) Using scan tool, erase DTCs. Start engine. Using scan
tool, read DTCs while wiggling wiring harness between 3-4 shift
solenoid and PCM. If DTC P0753 resets, repair wiring harness as
necessary. If DTC P0753 does not reset, go to next step.
4) Using wiring diagram as a guide, inspect wiring and
connectors. Repair wiring harness as necessary. If wiring and
connectors are okay, see INACTIVE DTC CONDITION under SELF-DIAGNOSTIC
SYSTEM. Testing is complete.
5) Turn ignition off. Disconnect transmission solenoid
harness connector. Turn ignition on. Using scan tool, actuate
transmission control relay. Measure voltage between ground and
transmission relay output circuit at transmission solenoid harness
connector. If voltage does not switch from zero to greater than 10
volts, go to step 16). If voltage switches from zero to greater than
10 volts, go to next step.
6) Turn ignition off. Disconnect PCM harness connectors.
Inspect connectors and terminals for damage. Repair as necessary. If
connectors and terminals are okay, turn ignition on. Measure voltage
between ground and 3-4 shift solenoid control circuit at transmission
solenoid harness connector. If voltage is greater than 10 volts, go to
next step. If voltage is 10 volts or less, go to step 8).
7) Repair 3-4 shift solenoid control circuit for short to
voltage. Reconnect all disconnected harness connectors. Road test
vehicle and reach a speed of 50 MPH. Depress Overdrive (OD) switch 4
connector. If resistance is 5 ohms or greater, repair open 3-4 shift
solenoid circuit. If resistance is less than 5 ohms, replace
transmission solenoid and harness assembly.
12) Measure resistance between transmission control relay
output circuit at transmission control relay connector and 3-4 shift
solenoid control circuit at White PCM harness connector C2. If
resistance is 26-40 ohms, replace PCM. If resistance is not 26-40
ohms, test is complete.
13) Remove transmission control relay. Inspect transmission
control relay connector and terminals for damage. Repair as necessary.
If connector and terminals are okay, turn ignition on. Measure voltage
between ground and fused B+ circuit at transmission control relay
connector. If voltage is 10 volts or less, repair open fused B+
circuit. If voltage is greater than 10 volts, go to next step.
14) Turn ignition off. Measure resistance of transmission
control relay output circuit at transmission control relay connector
and TCC solenoid harness connector. If resistance is greater than 5
ohms, repair open transmission control relay output circuit. If
resistance is 5 ohms or less, go to next step.
15) Measure resistance between ground and transmission
control relay output circuit at transmission solenoid harness
connector. If resistance is less than 5 ohms, repair short to ground
in transmission control relay output circuit. If resistance is 5 ohms
or greater, replace transmission control relay.
16) Using scan tool, erase DTCs. Start engine. Attempt to
duplicate data and reset code. Using wiring diagram as a guide,
inspect wiring and connectors. Repair wiring harness as necessary. If
wiring and connectors are okay, go to next step.
17) Wiggle wiring harness between TCC solenoid and PCM. Note
if DTC P0753 resets. If DTC P0753 resets, repair wiring harness as
necessary. If DTC P0753 does not reset, replace PCM and see INACTIVE
DTC CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
Diagnostic Procedure (WJ Body)
NOTE: If all solenoid codes, P0743, P0748 and P0753 are set, go to
test DTC P1765: TRANS 12-VOLT SUPPLY RELAY CNTRL CIRCUIT
before proceeding.
1) Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIPS
counter is not displayed or displayed count is not "0", go to next
step. If DTC SPECIFIC GOOD TRIPS counter is displayed and displayed
count is "0", go to step 16).
2) Road test vehicle and reach a speed of 50 MPH. Depress
Overdrive (OD) switch 4 times so that vehicle attempts to shift from
4th gear to 3rd gear and back. If vehicle does not shift between 3rd
and 4th gear, go to step 4). If vehicle shifts between 3rd and 4th
gear, go to next step.
3) Record freeze frame data to determine conditions when code
was set. Using wiring diagram as a guide, inspect wiring and
connectors. Repair wiring harness as necessary. If wiring and
connectors are okay, see INACTIVE DTC CONDITION under SELF-DIAGNOSTIC
SYSTEM. Testing is complete.
4) Turn ignition off. Disconnect transmission solenoid
harness connector. Inspect connector and terminals for damage. Repair
as necessary. If connector and terminals are okay, turn ignition on.
Using scan tool, actuate transmission control relay. Measure voltage
between ground and transmission relay output circuit at transmission
solenoid harness connector. If voltage does not switch from zero to
greater than 10 volts, go to step 12). If voltage switches from zero
to greater than 10 volts, go to next step.
5) Turn ignition off. Disconnect PCM harness connectors.
Inspect connectors and terminals for damage. Repair as necessary. If