Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Turn the ignition On.
2. With the scan tool, read Transmission Control Module (TCM) DTCs and record on the repair order.
  Is this DTC active?
  
  Yes
  - Go To 2
  No
  - Perform the STORED LOST COMMUNICATION DTCS diagnostic procedure. Refer to STORED LOST COMMUNICATION DTCS .
CHECK THE CONTROLLER AREA NETWORK (CAN) DEDICATED POWERTRAIN (DPT) CIRCUIT VOLTAGE
1. Turn the ignition off.
2. Disconnect the ESM harness connector.
3. Turn the ignition on.
4. Measure the voltage between ground and the CAN DPT (+) circuit at the ESM harness connector.
5. Measure the voltage between ground and the CAN DPT (-) circuit at the ESM harness connector.
  Is the voltage between 2.4 and 2.6 volts for each circuit?
  
  Yes
  - Using the schematics as a guide, check the Electronic Shift Module (ESM) connector and all related in-line connector terminals for corrosion, damage, or pushed out terminals. Pay particular attention to the power and ground circuits. If no problems are found, replace the ESM in accordance with the Service Information. Refer to MODULE, ELECTRONIC SHIFT (ESM), REMOVAL .
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST - 948TE 9HP48 .
  No
  - Go To 3
CHECK CAN DPT CIRCUITS FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the TCM harness connector.
3. Measure the resistance of the CAN DPT (+) circuit between the ESM harness connector and the TCM harness connector.
4. Measure the resistance of the CAN DPT (-) circuit between the ESM harness connector and the TCM harness connector.
  Is the resistance below 3.0 Ohms for each circuit?
  
  Yes
  - Go To 4
  No
  - Repair the affected CAN DPT circuit(s) for an open or high resistance.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST - 948TE 9HP48 .
CHECK CAN DPT CIRCUITS FOR A SHORT TO GROUND
1. Check for continuity between ground and the CAN DPT (+) circuit at the TCM harness connector.
2. Check for continuity between ground and the CAN DPT (-) circuit at the TCM harness connector.
  Is there continuity between ground and the either of the CAN DPT circuits?
  
  Yes
  - Repair the affected CAN DPT circuit(s) for a short to ground.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST - 948TE 9HP48 .
  No
  - Go To 5
CHECK CAN DPT CIRCUITS FOR A SHORT TO ANOTHER CIRCUIT
1. Check for continuity between the CAN DPT (+) circuit and all other circuits at the TCM harness connector.
2. Check for continuity between the CAN DPT (-) circuit and all other circuits at the TCM harness connector.
  Is there continuity between either CAN DPT circuit and any other circuit?
  
  Yes
  - Repair the affected CAN DPT circuit(s) for a short to another circuit.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST - 948TE 9HP48 .
  No
  - Using the schematics as a guide, check the Electronic Shift Module (ESM) connector and all related in-line connector terminals for corrosion, damage, or pushed out terminals. Pay particular attention to the power and ground circuits. If no problems are found, replace the ESM in accordance with the Service Information. Refer to MODULE, ELECTRONIC SHIFT (ESM), REMOVAL .
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST - 948TE 9HP48 .