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AS68RC Automatic Transmission






P0707-TRANSMISSION RANGE SENSOR CIRCUIT LOW





For a complete wiring diagram refer to Diagrams/Electrical. Electrical Diagrams


Theory of Operation


The Transmission Range Sensor (TRS) is a multiple position selector switch which changes the signal path by redirecting a 12-volt signal source to seven different TRS signal circuits (P, R, N, D, 3, 2, 1) and also houses a Park/Neutral (P/N) switch circuit. These circuits are monitored by the Transmission Control Module and used in conjunction with various pressure switches to validate proper operation of the transmission and diagnose any possible problem. In a normal operating mode, pressure switch 8, is in an "Off" state in P, R, or N. and in an "On" state in any forward gear (engine running).


Condition One:


When Monitored:
- Ignition on in the run position.
- Pressure Switch 8 detected as "OFF"
- Output speed greater than or equal to 250 rpm.

Set Condition:
- If the Transmission Control Module (TCM) detects no shift lever position for the period of 2.0 sec.

Condition Two:


When Monitored:
- Ignition on in the run position.
- Shift lever position in P, R, D, 3, 2, or 1.

Set Condition:
- If the Transmission Control Module (TCM) detects shift lever positions P, R, D, 3, 2, or 1 up or down past N but does not detect N position for 4 or more times in one ignition cycle for the period of 500 msec.

Condition Three:


When Monitored:
- Ignition on in the run position.
- Shift lever position in P, N, D, 3, 2, or 1.

Set Condition:
- If the Transmission Control Module (TCM) detects shift lever positions P, N, D, 3, 2, or 1 up or down past R but does not detect the R position for 4 or more times in one ignition cycle for the period of 500 msec.







Always perform the AS68RC Pre-Diagnostic Troubleshooting procedure before proceeding. AS68RC Pre-Diagnostic Troubleshooting Procedure



Diagnostic Test


1. CHECK IF DTC IS CURRENT

NOTE: This DTC may set if the Transmission Range Sensor has been replaced or reinstalled and not properly adjusted (calibrated). Make sure the TRS is properly adjusted before attempting to perform this diagnostic procedure. If the TRS was improperly adjusted, adjust as necessary and perform AS68RC VERIFICATION TEST. Verification Tests

Ignition on, engine not running.

With the scan tool, read 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 12



2. CHECK IF DTC CONDITIONS

Ignition on, engine not running.

With the scan tool, monitor the TRS circuits while moving the shift lever several times to each gear position (P, R, N, D, 3, 2, and 1).

Pick the answer that best describes your findings:

No TRS circuits change from "Open" to "Closed"

- Go To 3

The Reverse (R) TRS position does not change from "Open" to "Closed"

- Go To 6

The Neutral (N) TRS position does not change from "Open" to "Closed"

- Go To 9

All TRS circuits seem to be working properly

- Go To 12



3. CHECK THE TRS CONNECTOR

Turn the ignition off to the lock position.

Inspect the TRS harness connector.

Is the TRS harness connector unplugged or not fully seated?

Yes

- Repair or replace the TRS harness connector as necessary.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- Go To 4



4. CHECK THE (F1) FUSED IGNITION SWITCH OUTPUT (OFF-RUN-START) CIRCUIT FOR AN OPEN





Turn the ignition off to the lock position.

Disconnect the TRS harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Ignition on, engine not running.

Using a test light connected to ground, check the (F1) Fused Ignition Switch Output (Off-Run-Start) circuit.


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?

Yes

- Go To 5

No

- Repair the (F1) Fused Ignition Switch Output (Off-Run-Start) circuit for an open.
- Perform AS68RC VERIFICATION TEST. Verification Tests



5. CHECK THE TRANSMISSION RANGE SENSOR





Ignition on, engine not running.

With the scan tool, monitor the TRS circuits in the following steps.

Using a jumper wire, jump each TRS circuit one at a time to the (F1) Fused Ignition Switch Output (Off-Run-Start) circuit in the TRS harness connector.

Do the TRS circuits read as "Closed" on each circuit when connected with a jumper wire?

Yes

- Replace the Transmission Range Sensor.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- 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


6. CHECK THE (T826) TRS REVERSE SIGNAL CIRCUIT





Turn the ignition off to the lock position.

Disconnect the TRS harness connector.

Using a jumper wire, connect the (F1) Fused Ignition Switch Output (Off-Run-Start) circuit to the (T826) TRS Reverse Signal circuit in the TRS harness connector.

Ignition on, engine not running.

With the scan tool, read the TRS Reverse state.

Does the scan tool read as "Closed"?

Yes

- Replace the Transmission Range Sensor.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- Go To 7



7. CHECK THE (T826) TRS REVERSE CIRCUIT FOR AN OPEN





Turn the ignition off to the lock position.

Disconnect the TCM C3 harness connector

Measure the resistance of the (T826) TRS Reverse Signal circuit between TRS harness connector and the TCM C3 harness connector.

Is the resistance above 5.0 ohms?

Yes

- Repair the (T826) TRS Reverse Signal circuit for an open.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- Go To 8



8. CHECK THE (T826) TRS REVERSE SIGNAL CIRCUIT FOR A SHORT TO GROUND





Measure the resistance between ground and the (T826) TRS Reverse Signal circuit.

Is the resistance below 100k ohms?

Yes

- Repair the (T826) TRS Reverse Signal circuit for a short to ground.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- 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



9. CHECK THE (T825) TRS NEUTRAL SIGNAL CIRCUIT





Turn the ignition off to the lock position.

Disconnect the TRS harness connector.

Using a jumper wire, connect the (F1) Fused Ignition Switch Output (Off-Run-Start) circuit to the (T825) TRS Neutral Signal circuit in the TRS harness connector.

Ignition on, engine not running.

With the scan tool, read the TRS Neutral state.

Does the scan tool read as "Closed"?

Yes

- Replace the Transmission Range Sensor.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- Go To 10



10. CHECK THE (T825) TRS NEUTRAL CIRCUIT FOR AN OPEN





Turn the ignition off to the lock position.

Disconnect the TCM C3 harness connector

Measure the resistance of the (T825) TRS Neutral Signal circuit between TRS harness connector and the TCM C3 harness connector.

Is the resistance above 5.0 ohms?

Yes

- Repair the (T825) TRS Neutral Signal circuit for an open.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- Go To 11



11. CHECK THE (T825) TRS NEUTRAL SIGNAL CIRCUIT FOR A SHORT TO GROUND





Measure the resistance between ground and the (T825) TRS Neutral Signal circuit.

Is the resistance below 100k ohms?

Yes

- Repair the (T825) TRS Neutral Signal circuit for a short to ground.
- Perform AS68RC VERIFICATION TEST. Verification Tests

No

- 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



12. CHECK WIRING AND CONNECTORS

With the scan tool, erase Transmission DTCs.

Test Drive the vehicle while perform multiple upshifts, downshifts, stops, shift to park then to drive.

With the scan tool, read Transmission DTCs.

Did the DTC reset?

Yes

- Go To 3

No

- Go To 13



13. 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.
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