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Home >> Jeep Truck >> 2007 >> Grand Cherokee 2WD V6-3.0L DSL Turbo VIN M >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0841

P0841






P0841-LR PRESSURE SWITCH RATIONALITY





For a complete wiring diagram Refer to Diagrams/Electrical Electrical Diagrams


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 45RFE/545RFE Pre-Diagnostic Troubleshooting procedure before proceeding. 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure








Diagnostic Test


1. CHECK FOR OTHER DTCS

Ignition on, engine not running.

With the scan tool, check for other transmission DTCs.

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

Yes

- Refer to the Transmission and Drivetrain and perform the appropriate symptom. If the DTC P0944 is present, perform its respective test first. P0944

No

- Go To 2



2. CHECK IF DTC P0841 IS PRESENT

With the scan tool, check the DTC EVENT DATA for P0841.


NOTE: Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test procedure.

Does the DTC EVENT DATA show the DTC P0841?

Yes

- Go To 3

No

- Refer to the Symptom Category and perform diagnostics for the DTC reported in the DTC EVENT DATA.



3. CHECK IF DTC SET IN REVERSE

Does the DTC 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 DTC 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

Turn the ignition off to the lock position.

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 can result in personal injury or death.


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

Install the Transmission Simulator, Miller tool #8333.

Ignition on, engine not running.

Turn the Pressure Switch selector to L/R on the Transmission Simulator.

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

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.

Were there any problems found?

Yes

- Repair as necessary.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 7



7. CHECK IF DTC SET IN FIRST GEAR

With the DTC EVENT DATA recorded earlier, check what gear the transmission was in when the DTC P0841 was set.

Does the DTC 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 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test



8. CHECK IF THE NO. 1 CHECK BALL IS CUT OR DAMAGED

Turn the ignition off to the lock position.

Remove the Transmission Valve Body.

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.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 9



9. CHECK IF THE REVERSE CARRIER SNAP RING IS DISLODGED

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 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Replace the Transmission Solenoid/TRS Assembly.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test



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





Turn the ignition off to the lock position.

Disconnect the Transmission Simulator, Miller tool #8333 if connected in a previous step or disconnect the Transmission Solenoid/TRS Assembly harness connector.

Disconnect the PCM C4 harness connector and connect Miller tool #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 Miller tool #8815 to perform diagnosis.

Measure the resistance of the (T50) L/R Pressure Switch Sense circuit between the Transmission Solenoid/TRS Assembly harness connector and the appropriate terminal of the Miller tool #8815.

Is the resistance above 5.0 ohms?

Yes

- Repair the (T50) L/R Pressure Switch Sense circuit for an open.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 11



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





Measure the resistance between ground and the (T50) L/R Pressure Switch Sense circuit.

Is the resistance below 5.0 ohms?

Yes

- Repair the (T50) L/R Pressure Switch Sense circuit for a short to ground.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 12



12. CHECK THE PCM POWERS AND GROUNDS

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 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 13



13. CHECK IF THE DTC RESETS

With the scan tool, clear the DTC and road test the vehicle.

Try to duplicate the conditions in which the DTC originally set using the DTC EVENT DATA recorded earlier.

Did the DTC P0841 reset?

Yes

- Replace the PCM. With the scan tool, perform QUICK LEARN.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 17



14. CHECK FOR LOW LINE PRESSURE

In the DTC 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. If the fluid level and Primary Oil Filter are OK, check the Main Regulator Valve in the Oil Pump.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 15



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





Turn the ignition off to the lock position.

Disconnect the Transmission Solenoid/TRS Assembly harness connector.

Disconnect all PCM harness connectors.

Measure the resistance between the (T50) L/R Pressure Switch Sense 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 Switch Sense circuit and all other circuit(s) in the Transmission Solenoid/TRS Assembly harness connector?

Yes

- Repair the (T50) L/R Pressure Switch Sense circuit for a short to other circuit(s).
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 16



16. CHECK IF DTC RESETS

With the scan tool, clear the DTC and road test the vehicle.

Try to duplicate the conditions in which the DTC originally set using the DTC EVENT DATA recorded earlier.

Did the DTC P0841 reset?

Yes

- Replace the Transmission Solenoid/TRS Assembly.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Go To 17



17. CHECK WIRING AND CONNECTORS

The conditions necessary to set this 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.

With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.

Were there any problems found?

Yes

- Repair as necessary.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. 45RFE/545RFE Transmission Verification Test

No

- Test Complete.
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