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P0841






P0841-LR PRESSURE SWITCH RATIONALITY





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Transmission system uses five pressure switches to monitor the fluid pressure in the L/R, 2C, 4C, UD, and OD clutch circuits. The pressure switches are continuously monitored for the correct states in each gear as shown.

- When Monitored:
Continuously with the ignition on and engine running.

- Set Condition:
The DTC will set if the L/R Pressure Switch reads open or closed at the wrong time in a given gear.





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






1. CHECK FOR OTHER DTCS
1. Ignition on; engine not running.
2. With the scan tool, check for other transmission DTCs.

Are there any Transmission Loss of Prime, TCM Power Input, and/or TIPM TCM Power Control Circuit DTCs present also?

Yes

- Perform the appropriate diagnostic procedure. If the DTC P0944 is present, perform its respective test first. P0944

No

- Go To 2

2. CHECK IF DTC P0841 IS PRESENT
1. With the scan tool, check the Event Data for P0841.

NOTE: Make sure to record all Event Data stored in the scan tool for future reference in this test procedure.

Does the Event Data show the DTC P0841?

Yes

- Go To 3

No

- Testing and InspectionPerform diagnostics for the DTC reported in the Event Data.

3. CHECK IF DTC SET IN REVERSE

Does the Event Data show the DTC P0841 set while in Reverse?

Yes

- Go To 10

No

- Go To 4

4. CHECK IF THE L/R PRESSURE SWITCH WAS CLOSED

Does the Event Data show the L/R Pressure Switch reading CLOSED when the DTC P0841 was set?

Yes

- Go To 5

No

- Go To 14

5. CHECK THE PCM AND WIRING
1. Turn the ignition off to the lock position.
2. Remove the Starter Relay.

CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.

WARNING: The Starter Relay must be removed from the PDC. Failure to do so may result in possible serious or fatal injury.

NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.

3. Install Transmission Simulator 8333.
4. Ignition on; engine not running.
5. Turn the Pressure Switch selector to L/R on the Transmission Simulator.
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 from open to closed while pressing the Pressure Switch Test button on the Transmission Simulator?

Yes

- Go To 6

No

- Go To 10

6. CHECK WIRING AND CONNECTORS
1. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
2. Wiggle the wires while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 7

7. CHECK IF DTC SET IN FIRST GEAR

In the Event Data recorded earlier, does the Event Data show the Present Gear as first gear when the DTC P0841 was set ?

Yes

- Go To 8

No

- Replace the Transmission Solenoid/TRS Assembly.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

8. CHECK IF THE NO. 1 CHECK BALL IS CUT OR DAMAGED
1. Turn the ignition off to the lock position.
2. Remove the Transmission Valve Body.
3. Check the No. 1 Check Ball for any possible cuts or damage.

Is the No. 1 Check Ball cut or damaged?

Yes

- Replace the No. 1 Check Ball and check for clutch debris in the transmission oil pan. If there is excessive debris, perform internal repairs to the L/R Clutch assembly. Refer to the Service Information for proper repair procedures.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 9

9. CHECK IF THE REVERSE CARRIER SNAP RING IS DISLODGED
1. Looking through the windows in the bottom of the case, check whether the snap ring at the front of the Reverse (center) Carrier has dislodged.

NOTE: It may be necessary to pry the Input Annulus Gear Shell rearward to check this snap ring.

Is the Reverse Carrier Snap Ring dislodged?

Yes

- Repair as necessary.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Replace the Transmission Solenoid/TRS Assembly.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

10. CHECK THE (T50) L/R PRESSURE CONTROL CIRCUIT FOR AN OPEN




1. Turn the ignition off to the lock position.
2. Disconnect the Transmission Simulator 8333 if connected in a previous step or disconnect the Transmission Solenoid/TRS Assembly harness connector.
3. Disconnect the PCM C4 harness connector and connect the PCM Pinout Box 8815.

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 the PCM Pinout Box 8815 to perform diagnosis.

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

Is the resistance above 5.0 Ohms?

Yes

- Repair the (T50) L/R Pressure Control circuit for an open.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 11

11. CHECK THE (T50) L/R PRESSURE CONTROL CIRCUIT FOR A SHORT TO GROUND




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

Is the resistance below 5.0 Ohms?

Yes

- Repair the (T50) L/R Pressure Control circuit for a short to ground.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 12

12. CHECK THE PCM POWERS AND GROUNDS
1. Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 13

13. CHECK IF THE DTC RESETS
1. With the scan tool, clear the DTC and road test the vehicle.
2. Try to duplicate the conditions in which the DTC originally set using the Event Data recorded earlier.

Did the DTC P0841 reset?

Yes

- Replace and program the Powertrain Control Module (PCM). With the scan tool, perform Quick Learn. Quick Learn Procedure
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 17

14. CHECK FOR LOW LINE PRESSURE
1. In the Event Data recorded earlier, compare the Line Pressure and the Desired Line Pressure.

Is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?

Yes

- Repair as necessary to correct low line pressure. Check for low fluid level. Check the Primary Oil Filter seal for a split, crack, or improperly installed. Refer to the Service Information for the proper installation procedure. If the fluid level and Primary Oil Filter are OK, check the Main Regulator Valve in the Oil Pump.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 15

15. CHECK THE (T50) L/R PRESSURE CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT




1. Turn the ignition off to the lock position.
2. Disconnect the Transmission Solenoid/TRS Assembly harness connector.
3. Disconnect all PCM harness connectors.
4. Measure the resistance between the (T50) L/R Pressure Control circuit and all other circuits in the Transmission Solenoid/TRS Assembly harness connector.

Is the resistance below 5.0 Ohms between the (T50) L/R Pressure Control circuit and all other circuit(s) in the Transmission Solenoid/TRS Assembly harness connector?

Yes

- Repair the (T50) L/R Pressure Control circuit for a short to other circuit(s).
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 16

16. CHECK IF DTC RESETS
1. With the scan tool, clear the DTC and road test the vehicle.
2. Try to duplicate the conditions in which the DTC originally set using the Event Data recorded earlier.

Did the DTC P0841 reset?

Yes

- Replace the Transmission Solenoid/TRS Assembly.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Go To 17

17. CHECK WIRING AND CONNECTORS
1. The conditions necessary to set this 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 545RFE TRANSMISSION VERIFICATION TEST. . 545RFE Transmission Verification Test

No

- Test Complete.

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