Diagnostic Test

1. With the scan tool, read DTCs.

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

   Yes 

   • Perform the appropriate diagnostic procedure.

   No 

   • Go To  2

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 

   • Refer to DIAGNOSTIC CODE INDEX and perform the diagnostic procedure identified in the Event Data.

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

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

Yes 

• Refer to DIAGNOSTIC CODE INDEX and perform the diagnostic procedure for the DTC P0882.

No 

• Go To  5

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

Yes 

• Go To  6

No 

• Go To  7

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 fluid level and adjust as necessary. If 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 

• 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. With the scan tool, read DTCs.

   Is the DTC P0871 also present?

   Yes 

   • Refer to DIAGNOSTIC CODE INDEX and perform the diagnostic procedure for P0871.

   No 

   • Go To  8

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

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

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 fluid level and adjust as necessary. If 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  15

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 4C Pressure Switch state while grounding the (T48) 4C Pressure Signal at the GPEC Diagnostic Adapter with a fused jumper wire.

   Did the 4C Pressure Switch state change from OPEN to CLOSED while grounding the (T48) 4C Pressure Signal?

   Yes 

   • Go To  12

   No 

   • Go To  13

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 

   • Repair as necessary.
   • 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. 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  14

   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 

• 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 the PCM in accordance with the Service Information. Refer to REMOVAL AND INSTALLATION .
• With the scan tool, perform Quick Learn.
• Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

1. Turn the Ignition off.
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. Refer to the Service Information.

   Where there any problems found?

   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.

   • 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.
   • 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  16

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 

   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.

   • Repair as necessary. Refer to the Service Information.
   • 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 .
   • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .