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.

CHECK FOR RELATED DTCS
1. With the scan tool, read TCM DTCs and record on the repair order.
  Is DTC P0933 set?
  
  Yes
  - Repair DTC P0933. Refer to P0933-HYDRAULIC PRESSURE SENSOR RANGE/PERFORMANCE .
  No
  - Go To 2
CHECK FOR AN ACTIVE DTC
1. Record the Event Data and Environmental Data.
2. With the scan tool, erase DTCs.
3. Using the recorded Event and Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
4. With the scan tool, read TCM DTCs.
  Did the DTC return?
  
  Yes
  - Go To 3
  No
  - Go To 15
CHECK THE LINE PRESSURE SENSOR CONNECTION
1. Turn the ignition on, Engine Off .
2. With the scan tool, read the Line Pressure while firmly pushing the Line Pressure Sensor connector inwards towards the Transmission.
  Did the Line Pressure reading on the scan tool CHANGE to about 207 kPa (30 psi) or 0.7 volts when the connector was pushed inward?
  
  Yes (value was different and changed to 207 kPa (30 psi) or 0.7 volts).
  - Disconnect and properly reconnect the Line Pressure Sensor connector. Inspect terminals and repair as necessary.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 4
CHECK THE LINE PRESSURE
1. Turn the ignition off.
2. Install the Line Pressure Adaptor (special tool #8259, Adapter, Pressure Test), and the 0-300 psi Pressure Gauge (special tool #C-3293-SP, Gauge, Pressure 0-300 P.S.I.).
3. Start the engine in PARK.
  NOTE:
  The Desired Line Pressure value may change depending on if the Brake Pedal is pressed or released.
4. Monitor the line pressure readings of both the scan tool and the pressure gauge and compare the two readings.
  Is the line pressure gauge reading within 34 kPa (5 psi) of the scan tool reading?
  
  Yes
  - Go To 13
  No
  - Go To 5
CHECK THE (F856) 5-VOLT SUPPLY
1. Turn the ignition off.
2. Disconnect the Line Pressure sensor harness connector.
3. Turn the ignition on.
  - Measure the voltage on the (F856) 5-Volt Supply circuit in the Line Pressure sensor harness connector.
  Is the voltage above 4.8 volts?
  
  Yes
  - Go To 9
  No
  - Go To 6
CHECK FOR THE (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
1. Measure the resistance between the (F856) Line Pressure Sensor 5-Volt Supply circuit and the (K900) Sensor Ground circuit at the Transmission Line Pressure Sensor harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 7
  No
  - Repair the (F856) 5-Volt Supply circuit for a short to the (K900) Sensor Ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to 5.7L - DIAGNOSTIC TEST or 5.7L CNG - DIAGNOSTIC TEST or 6.4L - DIAGNOSTIC TEST or POWERTRAIN VERIFICATION TEST - 6.7L .
CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
1. Disconnect the PCM C2 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 GPEC Diagnostic Adaptor to perform the diagnosis.
2. Important: The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the PCM harness connector.
4. Check for continuity between ground and the (F856) 5-Volt Supply circuit at the GPEC Diagnostic Adaptor.
  Is there continuity between ground and the (F856) 5-Volt Supply circuit?
  
  Yes
  - Repair the (F856) 5-Volt Supply circuit for a short to ground.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 8
CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance of the (F856) 5-volt Supply circuit between the Line Pressure Sensor harness connector and the appropriate terminal of the GPEC Diagnostic Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 9
  No
  - Repair the (F856) 5-volt Supply circuit for an open.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
CHECK THE (T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C1 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 GPEC Diagnostic Adaptor to perform the diagnosis.
3. Important: The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.
4. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the PCM harness connector.
5. Measure the resistance between ground and the (T38) Line Pressure Sensor Signal circuit at the Line Pressure Sensor harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 10
  No
  - Repair the (T38) Transmission Line Pressure Sensor Signal circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to 5.7L - DIAGNOSTIC TEST or 5.7L CNG - DIAGNOSTIC TEST or 6.4L - DIAGNOSTIC TEST or POWERTRAIN VERIFICATION TEST - 6.7L .
CHECK FOR THE (T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
1. Measure the resistance between the (T38) Line Pressure Sensor Signal circuit and the (K900) Sensor Ground circuit at the Line Pressure Sensor harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 11
  No
  - Repair the (T38) Line Pressure Sensor Signal circuit for a short to the (K900) Sensor Ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to 5.7L - DIAGNOSTIC TEST or 5.7L CNG - DIAGNOSTIC TEST or 6.4L - DIAGNOSTIC TEST or POWERTRAIN VERIFICATION TEST - 6.7L .
CHECK THE (T38) LINE PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
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 GPEC Diagnostic Adaptor to perform the diagnosis.
1. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the PCM harness connector.
2. Measure the resistance of the (T38) Line Pressure Sensor Signal circuit between the Line Pressure Sensor harness connector and the GPEC Adaptor.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 12
  No
  - Repair the (T38) Line Pressure Sensor Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to 5.7L - DIAGNOSTIC TEST or 5.7L CNG - DIAGNOSTIC TEST or 6.4L - DIAGNOSTIC TEST or POWERTRAIN VERIFICATION TEST - 6.7L .
CHECK THE LINE PRESSURE SENSOR
1. Turn the ignition off.
2. Disconnect the Line Pressure Sensor.
3. Connect a jumper wire between the (F856) 5-Volt supply and the (T38) Line Pressure Sensor signal circuits at the line pressure connector.
4. Turn the ignition on.
5. With the scan tool, read the Line Pressure Sensor signal voltage.
  Is the voltage above 4.8 volts with the jumper in place?
  
  Yes
  - Replace the Line Pressure Sensor in accordance with the Service Information.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Replace the PCM in accordance with the Service Information.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
CHECK THE (T118) LINE PRESSURE VARIABLE FORCE SOLENOID CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
1. Turn the ignition off.
2. 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 the GPEC Diagnostic Adaptor to perform the diagnosis.
3. Important: The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.
4. Disconnect the PCM C1 harness connector.
5. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the PCM harness connector.
6. Check for continuity between the (T118) Line Pressure Variable Force Solenoid Control circuit and all other circuits at the GPEC Diagnostic Adaptor.
  Is there continuity between the (T118) Line Pressure Variable Force Solenoid Control circuit and any other circuit?
  
  Yes
  - Repair the (T118) Line Pressure Variable Force Solenoid Control circuit for a short to another circuit.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Go To 14
CHECK FOR A PLUGGED TRANSMISSION OIL FILTER
1. Turn the ignition off.
2. Remove and inspect the Transmission Oil Pan for excessive debris in accordance with the Service Information.
3. Remove and inspect the Primary Oil Filter in accordance with the Service Information.
  NOTE:
  Make sure the Primary Transmission Oil Filter and or O-ring is not cracked or split.
  
  Does the Oil Pan contain excessive debris and or is the Primary Oil Filter cracked or plugged?
  
  Yes
  - Repair the plugged, cracked or split Primary Transmission Oil Filter and or O-ring. If the Primary Transmission Oil Filter is plugged, refer to 66RFE AUTOMATIC TRANSMISSION - (SERVICE INFORMATION) - 2500 HD for the proper hydraulic repair procedure.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  No
  - Repair internal Transmission and inspect the Transmission Oil Pump in accordance with the Service Information and replace if necessary. If no problem is found, replace the Solenoid/TRS Assembly.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
CHECK TRANSMISSION OIL COOLER RETURN FILTER
NOTE:
P0868 can be caused by torque converter drainback (transmission oil draining out of the torque converter while the engine is off). Often, a customer complaint of slippage, lack of movement, delayed engagement, etc. (after sitting overnight, or for an hour or more when warm) will indicate torque converter drainback.

Review the recorded Event Data and Environmental Data to see if P0868 set shortly after a restart (time since start less than 2 minutes).

Was the original P0868 fault set shortly after an engine restart?

Yes
- Replace the cooler return (spin-on) filter in the transmission in accordance with the Service Information. Refer to FLUID AND FILTER, STANDARD PROCEDURE .
- If the transmission oil cooler return filter was already replaced for this issue and the DTC returned, remove the transmission and replace the transmission oil pump assembly in accordance with the Service Information. Refer to REMOVAL .
- Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
No
- Go To 16
CHECK 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. Check for any Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the TRANSMISSION VERIFICATION TEST. (Refer to 66RFE TRANSMISSION VERIFICATION TEST ).
  No
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to 66RFE TRANSMISSION VERIFICATION TEST .
  - Test Complete.