62TE

P0841-L/R PRESSURE SWITCH RATIONALITY







Theory of Operation

The Transmission system uses three pressure switches to monitor the fluid pressure in the L/R, 2/4, and OD elements. The pressure switches are continuously monitored for the correct states in each gear. If the set condition (invalid LR pressure switch state) is identified, 1st gear and torque converter lock-up (EMCC) will be inhibited. The vehicle will launch in 2nd gear and shift normally through the gears without allowing EMCC. If during the same key start, the invalid LR pressure switch state is no longer present, the transmission will return to normal operation (1st and EMCC available). Limp-in will not occur unless DTC P0841 is accompanied by a code P0706 and the MIL will illuminate after five minutes of substituted operation.

- When Monitored:
Whenever the engine is running.

- Set Condition:
The DTC is set if the L/R pressure switch is open or closed at the wrong time in a given gear. If the problem is identified for three successive key starts, the transmission will go into Limp-in mode and the MIL will turn on after 10 seconds of vehicle operation.





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

PRESSURE SWITCH STATES






1. CHECK IF RELATED TCM DTCS ARE PRESENT
1. With the scan tool, read DTCs

Are there any TCM Power Input DTCs present also?

Yes

- Testing and Inspection Perform the appropriate diagnostic procedure.

No

- Go To 2

2. CHECK FOR LOSS OF PRIME DTC
1. With the scan tool, check for other DTCs.

Is the DTC P0944 present also?

Yes

- P0944 Perform the appropriate diagnostic procedure.

No

- Go To 3

3. CHECK TO SEE IF P0841 IS CURRENT
1. With the scan tool, view DTCs.

Is the status active for this DTC or is the Starts Since Set counter 2 or less?

Yes

- Go To 4

No

- Go To 8

4. PCM AND WIRING
1. Turn the ignition off to the lock position.
2. Remove the Ignition Switch Feed fuse from the TIPM.

CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being started in gear.

WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in possible serious or fatal injury.

3. Install the Transmission Simulator 8333A and the Electronic Transmission Adapter kit.

NOTE: Check connectors - Clean/repair as necessary.

4. Ignition on, engine not running.
5. With the Transmission Simulator, turn the Pressure Switch selector to L/R.
6. With the scan tool, monitor the L/R Pressure Switch state while pressing the Pressure Switch Test button on the Transmission Simulator.

Did the L/R Pressure Switch state change?

Yes

- Replace the Transmission Solenoid/TRS Assembly.
- Perform the 62TE TRANSMISSION VERIFICATION TEST. 62TE Transmission Verification Test.

No

- Go To 5

5. (T50) L/R PRESSURE SIGNAL CIRCUIT OPEN




1. Turn the ignition off to the lock position.
2. Disconnect the PCM C4 harness connector.
3. Disconnect the Transmission Solenoid/TRS Assembly harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install PCM Pinout Box 8815 to perform diagnosis.

4. Measure the resistance of the (T50) L/R Pressure Signal circuit from the appropriate terminal of the PCM Pinout Box 8815 and the Transmission Solenoid/TRS Assembly harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the (T50) L/R Pressure Signal circuit for an open.
- Perform the 62TE TRANSMISSION VERIFICATION TEST. 62TE Transmission Verification Test.

No

- Go To 6

6. (T50) L/R PRESSURE SIGNAL CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (T50) L/R Pressure Signal circuit.

Is the resistance below 5.0 Ohms?

Yes

- Repair the (T50) L/R Pressure Signal circuit for a short to ground.
- Perform the 62TE TRANSMISSION VERIFICATION TEST. 62TE Transmission Verification Test.

No

- Go To 7

7. (T50) L/R PRESSURE SIGNAL CIRCUIT SHORTED TO VOLTAGE




1. Remove the Transmission Control Relay.
2. Connect a jumper wire between the (A104) B (+) circuit and (T16) Transmission Control Relay Output circuit.
3. Ignition on, engine not running.
4. Measure the voltage of the (T50) L/R Pressure Signal circuit.

Is the voltage above 0.5 of a volt?

Yes

- Repair the (T50) L/R Pressure Signal circuit for a short to voltage.
- Perform the 62TE TRANSMISSION VERIFICATION TEST. 62TE Transmission Verification Test.

No

- Replace and program the Powertrain Control Module. With the scan tool perform Quick Learn Quick Learn Procedure.
- Perform the 62TE TRANSMISSION VERIFICATION TEST. 62TE Transmission Verification Test.

8. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.
4. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the 62TE TRANSMISSION VERIFICATION TEST. 62TE Transmission Verification Test.

No

- Test Complete.