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Home >> Jeep >> 2020 >> Grand Cherokee Trackhawk >> Repair and Diagnosis >> External Pages >> Different car >> Section 225 (As69RC Automatic Transmission - DTCS C1400-00 To P0869-00 - 3500HD) >> DTC Troubleshooting >> P0702-00-Transmission Control System Electrical >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2019 RAM 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR DTC TO RETURN 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
    2. With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
    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 recorded Environmental Data and the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read DTCs.

    Did the DTC return?

    Yes 

    • Go To  2

    No 

    • Go To  10
  2. CHECK FOR BCM DTCS 
    1. With the scan tool, read BCM DTCs.

      Are any BCM Ignition Run/Start relay control DTC(s) stored?

      Yes 

      No 

      • Go To  3
  3. CHECK THE (F946) IGNITION RUN/START CIRCUIT STATUS 
    1. Turn the ignition on.
    2. With the scan tool, read the Ignition Run/Start (Run IG2 Switch) status.

      Does the Ignition Run/Start (Run IG2 Switch) status indicate OPEN?

      Yes 

      • Go To  4

      No 

      • Go To  10
  4. CHECK THE F77 FUSE 
    1. Turn the ignition off.
    2. Check the F77 fuse for an open.

      Is the fuse open?

      Yes 

      • Go To  8

      No 

      • Go To  5
  5. CHECK POWER DISTRIBUTION CENTER (PDC) HARNESS CONNECTIONS 
    1. Disconnect and isolate the negative battery cable.
    2. Using the wiring diagram for reference, disconnect the related PDC harness connectors.
    3. Inspect harness 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.
      • 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.

      Were any problems found?

      Yes 

      No 

      • Go To  6
  6. CHECK THE (F946) IGNITION RUN/START CIRCUIT FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the TCM C1 harness connector.
    3. Connect the positive lead of the load test tool to the 12.0 volt supply circuit at the component harness connector (A). Note:  refer to the diagram below.
    4. Connect the negative lead of the load test tool to the ground circuit of the Battery or a good chassis ground.
    5. Ensure that the circuit being tested is being powered on. If the 12.0 volt circuit being tested is an ignition feed for example, the ignition must be on. If testing an output from a relay, verify that the relay is energized and on.
    6. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
    NOTE:

    Note: Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to STANDARD PROCEDURE .

    NOTE:

    Note:  A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

    NOTE:

    Note: Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

    • 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
    • 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
    • 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

    Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to STANDARD PROCEDURE .

    GC0174938Courtesy of CHRYSLER GROUP, LLC
    NOTE:

    When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.

    NOTE:

    Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

    Is the load test bulb illuminated and bright?

    Yes 

    • Go To  9

    No 

    • Go To  7
  7. CHECK THE IGNITION RUN/START RELAY 
    1. Install a substitute Ignition Run/Start relay.
      1. Disconnect the component harness connector to isolate the 12.0 volt supply circuit.
      2. Connect the positive lead of the load test tool to the 12.0 volt supply circuit at the component harness connector (A). Note:  refer to the diagram below.
      3. Connect the negative lead of the load test tool to the ground circuit of the Battery or a good chassis ground.
      4. Ensure that the circuit being tested is being powered on. If the 12.0 volt circuit being tested is an ignition feed for example, the ignition must be on. If testing an output from a relay, verify that the relay is energized and on.
      5. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
      NOTE:

      Note: Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to STANDARD PROCEDURE .

      NOTE:

      Note:  A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Note: Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      • 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      • 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      • 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to STANDARD PROCEDURE .

      GC0174938Courtesy of CHRYSLER GROUP, LLC
      NOTE:

      When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.

      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright?

      Yes 

      • Replace the Ignition Run/Start Relay in accordance with the Service Information.
      • Perform the TRANSMISSION VERIFICATION TEST. Refer to TRANSMISSION VERIFICATION TEST .

      No 

      • Go To  9
  8. ISOLATE AND CHECK THE (F946) IGNITION RUN/START CIRCUIT FOR A SHORT TO GROUND 
    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.
    NOTE:

    When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.

    NOTE:

    There should be no continuity between ground and the circuit being tested.

    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  9
  9. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all TCM harness connectors.
    2. Disconnect all related in-line harness connections.
    3. Disconnect the related component harness connectors.
    4. 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.
      • 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.

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

      Did the DTC return?

      Yes 

      No 

  10. CHECK WIRING AND XY107A HARNESS CONNECTOR FOR INTERMITTENT CONNECTIONS 
    NOTE:

    The conditions necessary to set the DTC are not present at this time. The code set because of an intermittent condition. Try to determine the cause in this step.

    Turn the ignition off.

    1. Disconnect all TCM harness connectors.
    2. Disconnect all related in-line harness connections.
    3. Disconnect the related component harness connectors.
    4. 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.
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.
    5. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
    6. Wiggle the wires while checking for shorted or open circuits.

      Were any problems found?

      Yes 

      No 

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