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Home >> Jeep >> 2009 >> Commander Overland, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 24 (Electronic Control Modules - Electrical Diagnostics) >> Electronic Control Modules - Electrical Diagnostics >> DTC Troubleshooting >> *No Response From TCM - Nag1/Diesel >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2008 Jeep Commander. However, it is still accessible from the selected car via links, so may be relevant.
  1. TEST FOR INTERMITTENT CONDITION 

    Turn the ignition on.

    NOTE: Ensure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.

    With the scan tool, select ECU view.

    NOTE: A red X will be next to the module that is not communicating, indicating that the module is not active on the Bus network. A green check indicates that the module is active on the Bus network.
    NOTE: Check the FCM for any active CAN C hardware and any ignition related DTCs, perform DTCs before proceeding.
    NOTE: Ensure the (D223) SCI Transmit circuit is not shorted to voltage. This condition could potentially cause a no response condition to the TCM.

    Does the scan tool display a red X next to the module? 

    Yes 

    1. Go To step  2.

    No 

    1. The no response condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.
  2. (Z904) GROUND CIRCUIT OPEN 
    Fig 1: Checking (Z904) Ground Circuit
    GC0045381Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the Transmission Control Module C1 harness connector.

    Using a 12-volt test light connected to 12-volts, check the (Z904) ground circuit.

    Does the test light illuminate brightly? 

    Yes 

    1. Go To step  3.

    No 

    1. Repair the (Z904) ground circuit for an open.
    2. Perform NAG1 TRANSMISSION VERIFICATION TEST .
  3. (F946) TRANSMISSION RELAY OUTPUT CIRCUIT OPEN OR SHORTED 
    Fig 2: Checking (F946) Transmission Relay Output Circuit
    GC0045382Courtesy of CHRYSLER LLC

    Turn the ignition on.

    Using a 12-volt test light connected to ground, check the (F946) Transmission Relay Output circuit.

    Does the test light illuminate brightly? 

    Yes 

    1. Go To step  4.

    No 

    1. Repair the (F946) Transmission Relay Output circuit for an open or short.
    2. Perform NAG1 TRANSMISSION VERIFICATION TEST .
  4. (D65) CAN C BUS (+) CIRCUIT OPEN 
    Fig 3: Measuring Resistance Of (D65) CAN C Bus (+) Circuit Between FCM Connector And TCM Connector
    GC0045383Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the FCM C1 harness connector.

    Disconnect the TCM C2 harness connector.

    Measure the resistance of the (D65) CAN C Bus (+) circuit between the FCM connector and the TCM connector.

    Is resistance below 5.0 ohms? 

    Yes 

    1. Go To step  5.

    No 

    1. Repair the (D65) CAN C Bus (+) circuit for an open.
    2. Perform NAG1 TRANSMISSION VERIFICATION TEST .
  5. (D64) CAN C BUS (-) CIRCUIT OPEN 
    Fig 4: Measuring Resistance Of (D64) CAN C Bus (-) Circuit Between FCM Connector And TCM Connector
    GC0045384Courtesy of CHRYSLER LLC

    Measure the resistance of the (D64) CAN C Bus (-) circuit between the FCM connector and the TCM connector.

    Is resistance below 5.0 ohms? 

    Yes 

    1. Replace the Transmission Control Module in accordance with the service information.
    2. Perform NAG1 TRANSMISSION VERIFICATION TEST .

    No 

    1. Repair the (D64) CAN C Bus (-) circuit for an open.
    2. Perform NAG1 TRANSMISSION VERIFICATION TEST .
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