Transmission Code

(P0743) TCC SOLENOID CIRCUIT





When Monitored and Set Condition
- When Monitored: Always monitored with system active at each ignition cycle.
- Set Condition: If the TCM detects a short to ground or battery on the solenoid control circuit, shorted solenoid, open solenoid, or an open or shorted solenoid control circuit driver in the TOM.

POSSIBLE CAUSES
- TCC SOLENOID CONTROL CIRCUIT OPEN
- TCC SOLENOID CONTROL CIRCUIT SHORTED TO GROUND
- TCC SOLENOID CONTROL CIRCUIT SHORTED TO ANOTHER CIRCUIT TCC SOLENOID
- TRANSMISSION CONTROL MODULE

Diagnostic Test
1. PRE-DIAGNOSTIC CHECK OUT





Note: Low fluid level can be the cause of many transmission problems. If the fluid level is low, locate and repair the leak then check and adjust the fluid level in accordance with the Service Information.

Note: Always perform diagnostics with a fully charged battery to avoid false symptoms.
With the DRB III*, read the engine DTCs. Check and repair all engine DTCs prior to performing transmission symptom diagnostics.
With the DRB III*, read and record all Transmission DTCs.

Note: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary.
Most DTCs set on start up but some must be set by driving the vehicle such that all diagnostic monitors have run.

Note: Verify flash level of transmission controller. Some problems are corrected by software upgrades to the transmission controller.

Note: Check for any Technical Service Bulletins that may apply.

Perform this procedure prior to Symptom diagnosis.
Continue
Go To 2

2. CHECK FOR CURRENT DTC

Note: If the TCM detects and stores a DTC, the TCM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the DRB III* at the same time the DTC is displayed.

Note: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

Turn the ignition on.
With the DRB III*, erase TCM DTCs.

Note: It maybe necessary to road test the vehicle for this DTC to set. With the DRB III*, read the TCM DTCs.

Did this DTC set again?
Yes>>Go To 3
No>>Go To 7

3. TCC SOLENOID CONTROL CIRCUIT OPEN





Turn the ignition off.
Disconnect the Transmission Control Module C2 harness connector.
Disconnect the Transmission Solenoid Assembly harness connector

Note: Check connectors - Clean/repair as necessary.

Measure the resistance of the TCC Solenoid Control circuit from the TCM C2 harness connector to the Transmission Solenoid Assembly harness connector.
Is the resistance below 5.0 ohms?
Yes>>Go To 4
No>>Repair the TCC Solenoid Control circuit for an open.
Perform NAG1 TRANSMISSION VERIFICATION TEST.

4. TCC SOLENOID CONTROL CIRCUIT SHORT TO GROUND





With the ignition off.
Measure the resistance between ground and the TCC Solenoid Control circuit.
Is the resistance below 100 kohms?
Yes>>Repair the TCC Solenoid Control circuit for a short to ground.
Perform NAG1 TRANSMISSION VERIFICATION TEST. Verification Tests
No>>Go To 5

5. TCC SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS





With the ignition off.
Measure the resistance from the TCC Solenoid Control circuit to all other circuits at the Transmission Solenoid Assembly harness connector.
Is the resistance below 100 kohms between any other circuit?
Yes>>Repair the TCC Solenoid Control circuit for a short to other circuit(s).
Perform NAG1 TRANSMISSION VERIFICATION TEST.
No>>Go To 6

6. TCC SOLENOID RESISTANCE OUT OF TOLERANCE





With the ignition off.
Reconnect the Transmission Solenoid Assembly harness connector.
Measure the resistance from the TCC Solenoid Control circuit to the Solenoid Supply Voltage circuit at the Transmission Control Module C2 harness connector.
Is the resistance between 2.0 and 4.0 ohms?
Yes>>Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST.
No>>Replace the TCC Solenoid.
Perform NAG1 TRANSMISSION VERIFICATION TEST.

7. INTERMITTENT WIRING AND CONNECTORS
The condition that caused this DTC to set is currently not present. Inspect the related wiring harness for a possible intermittent condition.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorts and open circuits.

Note: Check for Technical Service Bulletins that may apply.

Were any problems found?
Yes>>Repair as necessary.
Perform NAG1 TRANSMISSION VERIFICATION TEST.
No>>Test Complete.