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Home >> Chrysler >> 2011 >> 300 C, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1616 ((Powertrain Control Module (Pcm) - Electrical Diagnostics - 68RFE Automatic Transmission - 2500 Hd)) >> DTC Troubleshooting >> P0988-4C Pressure Switch Rationality >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR RELATED DTCS 
    1. With the scan tool, read DTCs.

      Are there any TCM Power Control Circuit or TCM Power Input DTCs present?

      Yes 

      No 

      • Go To  2
  2. DTC DATA SHOW CURRENT DTC 
    1. With the scan tool, check the Event Data.
      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 data for DTC P0988?

      Yes 

      • Go To  3

      No 

  3. CHECK IF MULTIPLE DTCS ARE PRESENT 

    In the Event Data recorded earlier, are there two or more related Pressure Switch Sense DTCs present in addition to P0988?

    Yes 

    • Go To  4

    No 

    • Go To  7
  4. RELATED DTC PRESENT 

    In the Event Data recorded earlier, do all the pressure switches read CLOSED for P0988?

    Yes 

    No 

    • Go To  5
  5. CHECK IF THE PRESSURE SWITCHES READ OPEN 

    In the Event Data recorded earlier, do all the pressure switches read OPEN?

    Yes 

    • Go To  6

    No 

    • Go To  7
  6. CHECK FOR LOW LINE PRESSURE 

    In the Event Data recorded earlier, is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?

    Yes 

    No 

    • Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information.
    • Perform the 68RFE TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST  .
  7. CHECK IF THE DTC P0871 ALSO SET 
    1. With the scan tool, read DTCs.

      Is the DTC P0871 also present?

      Yes 

      No 

      • Go To  8
  8. CHECK IF THE DTC SET IN PARK, REVERSE OR NEUTRAL 

    In the Event Data recorded earlier, does the Event Data show the DTC P0988 set in Park, Neutral, or Reverse?

    Yes 

    • Go To  13

    No 

    • Go To  9
  9. CHECK IF THE Event Data READS CLOSED 

    In the Event Data recorded earlier, does the Event Data show the 4C Pressure Switch reading CLOSED?

    Yes 

    • Go To  11

    No 

    • Go To  10
  10. CHECK THE PRIMARY OIL FILTER SEAL 

    In the Event Data recorded earlier, is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?

    Yes 

    No 

    • Go To  15
  11. CHECK THE PCM AND WIRING USING THE TRANSMISSION SIMULATOR 
    1. Turn the ignition off.
    2. Remove the Starter Relay from the PDC.
      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.

    3. Install the Transmission Simulator (special tool #8333B, Simulator, Transmission).
    4. Ignition on, engine not running.
    5. With the Transmission Simulator, turn the Pressure Switch selector switch to the 4C position.
    6. With the scan tool, monitor the 4C Pressure Switch while pressing the Pressure Switch test button on the Transmission Simulator (special tool #8333B, Simulator, Transmission).

      Did the state of the 4C Pressure Switch change while pressing the Pressure Switch Test button?

      Yes 

      • Go To  12

      No 

      • Go To  13
  12. CHECK THE TRANSMISSION SOLENOID/TRS ASSEMBLY 
    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.

      Where there any problems found?

      Yes 

      No 

      • Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information.
      • Perform the 68RFE TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST  .
  13. CHECK THE (T48) 4C PRESSURE SWITCH SENSE CIRCUIT FOR AN OPEN 
    1. Turn the ignition off.
    2. Disconnect the Transmission Simulator (special tool #8333B, Simulator, Transmission).
    3. Disconnect the PCM C2 harness connector.
    4. Measure the resistance of the (T48) 4C Pressure Switch Sense circuit between the Transmission Solenoid/TRS Assembly harness connector and the appropriate terminal of the PCM C2 harness connector.

      Is the resistance above 5.0 Ohms?

      Yes 

      No 

      • Go To  14
  14. CHECK THE (T48) 4C PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND 
    1. Measure the resistance between ground and the (T48) 4C Pressure Switch Sense circuit.

      Is the resistance below 5.0 Ohms?

      Yes 

      No 

      • Replace the Powertrain Control Module in accordance with the Service Information. With the scan tool, perform the Quick Learn procedure.
      • Perform the 68RFE TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST  .
  15. CHECK IF THE NO. 5 AND/OR NO. 7 CHECK BALL IS CUT OR DAMAGED 
    1. Turn the Ignition off.
    2. Remove the Valve Body Assembly in accordance with the Service Information.
    3. Inspect the No. 5 and No. 7 check balls for any cuts or damage.
    4. Inspect the 4C accumulator piston and seals and also the 4C tower seal on top of the valve body. Refer to 68RFE AUTOMATIC TRANSMISSION - (SERVICE INFORMATION) - 2500 HD .

      Where there any problems found?

      Yes 

      No 

      • Go To  16
  16. CHECK FOR EXCESSIVE LEAKAGE WITHIN THE 4C CLUTCH CIRCUIT 
    1. Air check the 4C Clutch hydraulic circuit. Refer to 68RFE AUTOMATIC TRANSMISSION - (SERVICE INFORMATION) - 2500 HD .
      NOTE:

      This hydraulic clutch circuit contains a small bleed orifice. Small leakage is considered normal.

      Was there excessive air leakage in the 4C Clutch hydraulic circuit?

      Yes 

      No 

      • Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information.
      • Perform the 68RFE TRANSMISSION VERIFICATION TEST. Refer to 68RFE TRANSMISSION VERIFICATION TEST  .
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