Diagnostic Test

WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

DETERMINE IF RELATED TCM POWER INPUT DTCS ARE PRESENT
1. With the scan tool, read DTCs.
  Are TCM Power Input DTCs present?
  
  Yes
  - Refer to the DTC INDEX - 2500 HD & 3500 HD article and perform the appropriate diagnostic procedure.
  No
  - Go To 2
CHECK THE EVENT DATA
1. With the scan tool, check the Event Data.
  Does the Event Data show data for DTC P0988?
  
  Yes
  - Go To 3
  No
  - Refer to the DIAGNOSTIC CODE INDEX and perform the appropriate diagnostic procedure.
MULTIPLE DTCS PRESENT
1. With the scan tool, read DTCs.
  Are there two or more related Pressure Switch DTCs present in addition to P0988?
  
  Yes
  - Go To 4
  No
  - Go To 7
RELATED DTC PRESENT
1. With the scan tool, check the Event Data for P0988.
  NOTE:
  Make sure to record all Event Data stored in the scan tool for future reference in this test procedure.
  
  Do all the pressure switches read CLOSED in the Event Data for P0988?
  
  Yes
  - Refer to the DIAGNOSTIC CODE INDEX and perform diagnostics for DTC P0882.
  No
  - Go To 5
EVENT DATA READ OPEN
In the Event Data recorded earlier, do all the pressure switches read OPEN?

Yes
- Go To 6
No
- Go To 7
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
- Repair as necessary to correct low line pressure. Check the fluid level and adjust as necessary. If the fluid level is OK, check the Primary Oil Filter seal for a split, crack or improperly installed. If the filter and seal are OK, check the Main Regulator Valve in the Oil Pump. Refer to PUMP, TRANSMISSION OIL, DISASSEMBLY .
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
No
- Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Refer to ASSEMBLY, TRANSMISSION SOLENOID AND TRS, REMOVAL .
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
DTC P0871 ALSO PRESENT
1. With the scan tool, read DTCs.
  Is DTC P0871 present?
  
  Yes
  - Refer to the DIAGNOSTIC CODE INDEX and perform the appropriate diagnostic procedure.
  No
  - Go To 8
EVENT DATA READ PARK REVERSE OR NEUTRAL
In the Event Data recorded earlier, does the Event Data show the DTC set in Park, Neutral or Reverse for P0988?

Yes
- Go To 13
No
- Go To 9
EVENT DATA READ 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
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
- Repair as necessary to correct low line pressure. Check the fluid level and adjust as necessary. If the fluid level is OK, check the Primary Oil Filter seal for a split, crack or improperly installed. If the filter and seal are OK, check the Main Regulator Valve in the Oil Pump. Refer to PUMP, TRANSMISSION OIL, DISASSEMBLY .
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
No
- Go To 15
CHECK THE PCM AND WIRING USING THE TRANSMISSION SIMULATOR
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 the (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.
  Did the state of the 4C Pressure Switch change while pressing the Pressure Switch Test button?
  
  Yes
  - Go To 12
  No
  - Go To 13
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 any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL or MODULE, POWERTRAIN CONTROL, 6.7L DIESEL, REMOVAL .
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
CHECK THE (T48) 4C PRESSURE SIGNAL CIRCUIT FOR AN OPEN

Fig 1: Checking 4C Pressure Signal Circuit For An Open
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition OFF to the LOCK position.
2. Disconnect the (special tool #8333B, Simulator, Transmission).
3. Disconnect the PCM C4 harness connector.
4. Connect the (special tool #8815A, Kit, NGC, 38 Position) to the PCM C4 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 the Miller tool 8815A to perform diagnosis.
5. Measure the resistance of the (T48) 4C Pressure Signal circuit between the Transmission Solenoid/TRS Assembly harness connector and the appropriate terminal of the (special tool #8815A, Kit, NGC, 38 Position).
  Is the resistance above 5.0 ohms?
  
  Yes
  - Repair the (T48) 4C Pressure Signal circuit for an open.
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 14
CHECK THE (T48) 4C PRESSURE SIGNAL CIRCUIT FOR A SHORT TO GROUND

Fig 2: Checking 4C Pressure Signal Circuit For A Short To Ground
Courtesy of CHRYSLER GROUP, LLC
1. Measure the resistance between ground and the (T48) 4C Pressure Signal circuit.
  Is the resistance below 5.0 ohms?
  
  Yes
  - Repair the (T48) 4C Pressure Signal circuit for a short to ground.
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - 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. If no problems are found, replace and program the PCM in accordance with the Service Information. With the scan tool, perform a Quick Learn. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL or MODULE, POWERTRAIN CONTROL, 6.7L DIESEL REMOVAL .
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
NO. 5 CHECK BALL CUT OR DAMAGED
1. Turn the Ignition off to the lock position.
2. Remove the Valve Body Assembly in accordance with the Service Information.
3. Inspect the No. 5 check ball 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.
  Where any problems found?
  
  Yes
  - Repair as necessary. Check for excessive clutch debris in the transmission oil pan. If excessive clutch debris is present, repair 4C clutch as necessary. Refer to the Service Information for proper repair procedures. Refer to VALVE BODY, DISASSEMBLY .
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 16
EXCESSIVE FLUID LEAKAGE WITH 4C CLUTCH CIRCUIT
1. Air check the 4C Clutch hydraulic circuit. Refer to the Service Information.
  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
  - Repair as necessary. Refer to the Service Information.
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Refer to ASSEMBLY, TRANSMISSION SOLENOID AND TRS, REMOVAL .
  - Perform the 66RFE TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .