2007 Grand Cherokee WK Factory Service Manual 21 - TRANSMISSION AND TRANSFER CASE

P0743-TCC SOLENOID CIRCUIT





For a complete wiring diagram Refer to Section 8W

Theory of Operation


The TCC Solenoid is activated when the Transmission Control Module (TCM) determines that the Torque Converter Clutch should be activated. The Torque Converter Clutch is a variable slip torque clutch that allows control of the slip from 5.5% to 95.5% of lock-up. The Clutch is controlled by the TCC Solenoid which is pulse width modulated (PWM) to provide the desired amount of slip. The clutch requires both an electrical PWM of 1000Hz and an hydraulic PWM of 100Hz.



Possible Causes
 
(T75) TCC SOLENOID CONTROL CIRCUIT OPEN
 
(T75) TCC SOLENOID CONTROL CIRCUIT SHORT TO GROUND
 
TCC SOLENOID CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
 
TCC SOLENOID
 
TRANSMISSION CONTROL MODULE
 


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)



Diagnostic Test

1. CHECK IF THE DTC IS CURRENT

NOTE: If the TCM detects and stores a DTC, the TCM also stores the vehicles operating conditions under which the DTC originally set. This information is located in scan tool under Environmental Data. Before erasing any stored DTCs, record any available data to assist in duplicating the conditions in which the DTC originally set.


Turn the ignition off to the lock position.
With the scan tool, erase Transmission DTCs.
Using the Environmental Data recorded earlier, try to duplicate the conditions in which the DTC originally set. It may be necessary to test drive the vehicle.
With the scan tool, read Transmission DTCs.

Did the DTC P0743 reset?

Yes


No

2. CHECK THE (T75) TCC SOLENOID CONTROL CIRCUIT FOR AN OPEN



Turn the ignition off to the lock position.
Disconnect the TCM C2 harness connector.
Disconnect the Transmission Electrohydraulic Control Unit Assembly harness connector.
Measure the resistance of the (T75) TCC Solenoid Control circuit from the TCM C2 harness connector to the Transmission Electrohydraulic Control Unit Assembly harness connector.

Is the resistance below 5.0 ohms?

Yes


No

3. CHECK THE (T75) TCC SOLENOID CONTROL CIRCUIT FOR A SHORT TO GROUND



Measure the resistance between ground and the (T75) TCC Solenoid Control circuit.

Is the resistance below 5.0 ohms?

Yes


No

4. CHECK THE (T75) TCC SOLENOID CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT



Measure the resistance between the (T75) TCC Solenoid Control circuit and all other circuits in the Transmission Electrohydraulic Control Unit Assembly harness connector.

Is the resistance below 5.0 ohms between the (T75) TCC Solenoid Control circuit and any other circuit(s) in the Transmission Electrohydraulic Control Unit Assembly harness connector?

Yes


No

5. CHECK THE TCC SOLENOID RESISTANCE



Disconnect the Transmission Electrohydraulic Control Unit Assembly harness connector.
Measure the resistance of the TCC Solenoid between the (T75) TCC Solenoid Control circuit and the (T78) Solenoid Supply circuit in the TCM C2 harness connector.

Is the resistance between 2.0 and 4.0 ohms?

Yes


No

6. INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.

Were there any problems found?

Yes


No