Diagnostic Test

1. With the scan tool, read all DTCs and record on the repair order.

   Are any TCM Power Input, Line Pressure, and or Loss of Prime DTCs set?

   Yes 

   • Repair TCM Power Input, Line Pressure, and or Loss of Prime DTCs. If DTC P0944 is set, perform that diagnostic procedure first. Refer to DIAGNOSTIC CODE INDEX .

   No 

   • Go To  2

Are two or more pressure switch rationality DTCs set in addition to P0876?

Yes 

• Go To  3

No 

• Go To  4

1. With the scan tool, read and record 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 all pressure switches CLOSED?

   Yes 

   • Perform diagnostic procedure for DTC P0882 as if the DTC is Active. Refer to DIAGNOSTIC CODE INDEX .

   No 

   • Go To  4

1. With the scan tool, read TCM DTCs.

   Is DTC P2704 set?

   Yes 

   • Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Refer to ASSEMBLY, TRANSMISSION SOLENOID AND TRS, REMOVAL AND INSTALLATION .
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

   No 

   • Go To  5

In the Event Data recorded earlier, does the Event Data display information for DTC P0876?

Yes 

• Go To  6

No 

• Perform the diagnostic procedure for the DTC that is shown in the Event Data. Refer to DIAGNOSTIC CODE INDEX .

In the Event Data recorded earlier, did DTC P0876 set in PARK, NEUTRAL or REVERSE?

Yes 

• Go To  10

No 

• Go To  7

In the Event Data recorded earlier, did DTC P0876 set with the UD Pressure Switch CLOSED?

Yes 

• Go To  10

No 

• Go To  8

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 the Service Information for the above procedures.
• If the Valve Body or the TCC VFS solenoid is replaced, remove the external TCC VFS bar code label from the transmission case.
• Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

No 

• Go To  9

1. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
   1. The ignition must be off when performing a resistance check to find a short between circuits.
   2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. At this time leave all in-line connectors connected. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
   3. Connect one lead of the DVOM to the circuit being tested at the GPEC Diagnostic Adapter.
   4. With the other lead of the DVOM probe all other circuits at the GPEC Diagnostic Adapter.
   NOTE:

   With the circuit isolated there should be no continuity between the circuit being tested and any other circuit.

   Is there continuity between the circuit being tested and any other circuit?

   Yes 

   • Repair the short between the circuits that have continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

   No 

   • Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Refer to ASSEMBLY, TRANSMISSION SOLENOID AND TRS, REMOVAL AND INSTALLATION .
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

1. Turn the ignition off.
2. 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.

3. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
4. Turn the ignition on.
5. With the scan tool, read the UD Pressure Signal state while grounding the (T29) UD Pressure Signal at the GPEC Diagnostic Adapter with a fused jumper wire.

   Did the UD Pressure Switch state change from OPEN to CLOSED while grounding the (T29) UD Pressure Signal?

   Yes 

   • Go To  15

   No 

   • Go To  11

1. Important:  The GPEC Diagnostic Adapter can add up to 1.5 Ohms of resistance to the circuit.
2. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
   1. The ignition must be off when checking the continuity of a circuit.
   2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
   3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
   4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
   5. Connect the other lead to the circuit being tested at the GPEC Diagnostic Adapter and measure the resistance of the circuit.

   Is the resistance below 3.0 Ohms?

   Yes 

   • Go To  12

   No 

   • Repair the circuit for an open or high resistance.
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

1. The ignition must be off when checking a circuit for continuity to ground.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect the negative lead of the DVOM to a known good ground.
4. With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.

Is there continuity between ground and the circuit being tested?

Yes 

• Repair the circuit for a short to ground. Use the wiring diagram as a guide to trace the circuit and look for any in-line connectors to help isolate the location of the short.
• Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

No 

• Go To  13

1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. At this time leave all in-line connectors connected. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect one lead of the DVOM to the circuit being tested at the GPEC Diagnostic Adapter.
4. With the other lead of the DVOM probe all other circuits at the GPEC Diagnostic Adapter.

Is there continuity between the circuit being tested and any other circuit?

Yes 

• Repair the short between the circuits that have continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
• Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

No 

• Go To  14

1. Disconnect all PCM harness connectors.
2. Disconnect the (special tool #10436, Adapter, GPEC Diagnostic) and remove from the vehicle.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
   • Proper connector installation.
   • Damaged connector locks.
   • Corrosion.
   • Other signs of water intrusion.
   • Weather seal damage (if equipped).
   • Bent terminals.
   • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
   • Terminals that have been pushed back into the connector cavity.
   • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

   Repair any conditions that are found.

6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. 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.
11. With the scan tool, read PCM DTCs.

    Did the DTC return?

    Yes 

    NOTE:

    This transmission is equipped with a solenoid for the Torque Converter Clutch (TCC) that is a Variable Force Solenoid (VFS) with close tolerance Pressure/Inductance (PI) curve. If replacing the PCM, it is necessary to transfer the PI data from the old PCM to the new PCM using the scan tool. If the PCM being replaced is non-responsive, the PI data can be retrieved from a 2-D bar code on the exterior of the transmission case. This is done with the scan tool using the "Program Torque Converter Solenoid PI Curve" routine.

    Early build transmissions will have the 2-D barcode label on the right side of the transmission case. Late build transmissions will have the label attached to a machined pad at the top of the case, near the rear of the transmission. The data must be entered into the scan tool in order to upload the information to the PCM. In the event that the exterior BAR code is missing, or it is suspected that the valve body or TCC solenoid has been replaced without uploading the correct PI data into an existing PCM, the transmission oil pan must be removed to retrieve the information from the 2-D bar code on the body of the TCC solenoid.

    • Replace the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to REMOVAL AND INSTALLATION .
    • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

    No 

    • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .
    • Test complete.

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 Adapter can add up to 1.5 Ohms of resistance to the circuit.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
4. Check for continuity between ground and the (T29) UD Pressure Signal circuit at the GPEC Diagnostic Adapter while wiggling the wiring harness and connectors pertaining to the UD Pressure Switch.

   Is there continuity between ground and the (T29) UD Pressure Signal circuit?

   Yes 

   • Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Refer to ASSEMBLY, TRANSMISSION SOLENOID AND TRS, REMOVAL AND INSTALLATION .
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

   No 

   • Go To  16

1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
2. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
3. With the scan tool, erase all DTCs.
4. Turn the ignition off for a minimum of 10.0 seconds.
5. Turn the ignition on.
6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
7. With the scan tool, read DTCs.

Did the DTC return?

Yes 

• Go To  17

No 

• Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .

1. Remove the Valve Body in accordance with the Service Information. Refer to VALVE BODY, REMOVAL AND INSTALLATION .
2. Check the No. 2 check ball for cuts or damage.

   Is the No. 2 check ball cut or damaged?

   Yes 

   NOTE:

   This transmission is equipped with a solenoid for the Torque Converter Clutch (TCC) that is a Variable Force Solenoid (VFS) with close tolerance Pressure/Inductance (PI) curve. It is necessary to update the TCC solenoid PI data in the PCM when replacing the TCC solenoid, Valve Body or Transmission assembly. This is done with the scan tool using the "Program Torque Converter Solenoid PI Curve" routine. The PI data is located on a 2-D BAR code etched on the body of the TCC solenoid. The data must be entered into the scan tool in order to upload the information to the PCM.

   When replacing the TCC solenoid or Valve Body, obtain the PI data before installing the transmission oil pan. When replacing the transmission, the PI data can be obtained from a 2-D bar code on the exterior of the new transmission. Early build transmissions will have the 2-D barcode label on the right side of the transmission case. Late build transmissions will have the label attached to a machined pad at the top of the case, near the rear of the transmission. If it is suspected that the valve body or TCC VFS has been replaced without uploading the correct PI data into the PCM, the transmission oil pan must be removed to retrieve the information from the 2-D bar code on the body of the TCC solenoid.

   • Replace the No. 2 check ball. Check for excessive clutch debris in the oil pan. If excessive debris is present, check the UD Clutch and repair as necessary.
   • If the Valve Body or the TCC VFS solenoid is replaced, remove the external TCC VFS bar code label from the transmission case.
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

   No 

   • Replace the Transmission Solenoid/TRS Assembly in accordance with the Service Information. Refer to ASSEMBLY, TRANSMISSION SOLENOID AND TRS, REMOVAL AND INSTALLATION .
   • Check for excessive clutch debris in the oil pan. If excessive debris is present, check the UD Clutch and repair as necessary.
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .