P0702
P0702-TRANSMISSION CONTROL SYSTEM ELECTRICAL
For a complete wiring diagram refer to Diagrams/Electrical. Electrical Diagrams
Theory of Operation
The Transmission Control Output is used to supply the primary power to the TCM. When the ignition switch is in the run or crank position, the ignition switch provides and input to the TIPM. The TIPM then energizes the Transmission Control relay which provides voltage to the TCM.
- When Monitored:
Continuously with the Ignition on and the engine running.
- Set Condition:
The TCM detects low voltage on the Transmission Control Output while the engine speed is greater than 0 rpm for 15 seconds.
Always perform the AS68RC Pre-Diagnostic Troubleshooting procedure before proceeding. AS68RC Pre-Diagnostic Troubleshooting Procedure
Diagnostic Test
1. CHECK IF DTC IS CURRENT
With the scan tool, view Transmission DTCs.
Is the status Active or is the Starts Since Set counter 2 or less for this DTC?
Yes
- Go To 2
No
- Go To 8
2. CHECK FOR RELATED TIPM DTCS
With the scan tool, view TIPM DTCs.
Are there any TIPM power output codes stored?
Yes
- Refer to the Transmission category and perform the appropriate symptom.
No
- Go To 3
3. CHECK THE (T16) TRANSMISSION CONTROL OUTPUT CIRCUIT
Turn the ignition off to the lock position.
Disconnect the TCM C2 harness connector.
Ignition on, engine not running.
Using the scan tool, actuate the Transmission Control Output in the TIPM.
Using a 12-volt test light connected to ground, check both of the (T16) Transmission Control Output circuits on the appropriate terminal of TCM C2 harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly on both of the TCM (T16) Transmission Control Output circuits?
Yes
- Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply. If no problems are found, replace and program the TCM.
- Perform AS68RC VERIFICATION TEST. Verification Tests
No
- Go To 4
4. CHECK THE (T16) TRANSMISSION CONTROL OUTPUT CIRCUIT
Turn the ignition off to the lock position.
Install a substitute Transmission Control relay.
Ignition on, engine not running.
Using the scan tool, actuate the Transmission Control Output in the TIPM.
Using a 12-volt test light connected to ground, check both of the (T16) Transmission Control Output circuits on the appropriate terminal of TCM C2 harness connector.
Does the test light illuminate brightly on both of the TCM (T16) Transmission Control Output circuits?
Yes
- Replace the Transmission Control Relay.
- Perform AS68RC VERIFICATION TEST. Verification Tests
No
- Go To 5
5. CHECK THE (A916) BATTERY FEED CIRCUIT
Turn the ignition off to the lock position.
Remove Transmission Control relay.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, check the (A916) Battery Feed circuit at the Transmission Control relay harness connector.
Does the test light illuminate brightly on the (A916) Battery Feed circuit?
Yes
- Go To 6
No
- Check the (A916) Battery Feed circuit for and open or short to ground. If no problems are found, replace the TIPM.
- Perform AS68RC VERIFICATION TEST. Verification Tests
6. CHECK THE (T16) TRANSMISSION CONTROL OUTPUT CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Measure the resistance of the (T16) Transmission Control Output circuit between the TCM C2 harness connector and the Transmission Control relay harness connector.
Is the resistance above 5.0 ohms?
Yes
- Repair the (T16) Transmission Control Output circuit for an open.
- Perform AS68RC VERIFICATION TEST. Verification Tests
No
- Go To 7
7. CHECK THE (T16) TRANSMISSION CONTROL OUTPUT CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T16) Transmission Control Output circuit.
Is the resistance below 100k ohms?
Yes
- Repair the (T16) Transmission Control Output circuit for a short to ground.
- Perform AS68RC VERIFICATION TEST. Verification Tests
No
- Using the schematics as a guide, check the Totally Integrated Power Module (TIPM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply. If no problems are found, replace the TIPM.
8. CHECK WIRING AND CONNECTORS
The conditions necessary to set the DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.
Check for any Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform AS68RC VERIFICATION TEST. Verification Tests
No
- Test Complete.