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Diagnostic Test

  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECU's) 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 Steering Column Control Module (SCCM) DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect the SCCM C3 harness connector.
    2. Disconnect the Speed Control Switch harness connector.
    3. Inspect SCCM and Speed Control Switch harness connectors and including 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.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    4. Connect all disconnected harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    5. With the scan tool, erase DTCs.
    6. Operate the vehicle in accordance with the when monitored and set conditions.
    7. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  3

      No 

      • The wiring or poor connection has been repaired.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  3. CHECK THE (D592) LIN BUS CIRCUIT FOR AN OPEN OR HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the SCCM C3 harness connector.
    3. Disconnect the Speed Control Switch harness connector.
    4. Measure the resistance of the (D592) LIN Bus circuit between the SCCM C3 harness connector and the Speed Control Switch harness connector
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector pins.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  4

      No 

      • Repair the (D592) LIN Bus circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  4. CHECK THE (D592) LIN BUS CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT 
    1. Check for continuity between the (D592) LIN Bus circuit and every other circuit in the Speed Control Switch harness connector.

      Is there any continuity between the (D592) LIN Bus circuit and any other circuit?

      Yes 

      • Repair the (D592) LIN Bus circuit for a short to another circuit.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE (D592) LIN BUS CIRCUIT FOR A SHORT TO GROUND 
    1. Check for continuity between ground and the (D592) LIN Bus circuit at the Speed Control Switch harness connector.

      Is there continuity between ground and the (D592) LIN Bus circuit?

      Yes 

      • Repair the (D592) LIN Bus circuit for a short to ground.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Go To  6
  6. CHECK THE (A92) FUSED B(+) CIRCUIT FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT 
    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:

      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: CIRCUIT LOAD TESTING PROCEDURES .

      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:

      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: CIRCUIT LOAD TESTING PROCEDURES .

      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.

      GC0174938Courtesy of CHRYSLER GROUP, LLC

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  7

      No 

      • Repair the 12.0 volt circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  7. CHECK THE (Z92) GROUND CIRCUIT FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT 
    1. Disconnect the component harness connector to isolate the ground circuit.
    2. Connect the positive lead of the load test tool to the positive side of the Battery.
    3. Connect the negative lead of the load test tool to the ground circuit at the component harness connector (A). Note:  refer to the diagram below.
    4. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
      GC0174957Courtesy of CHRYSLER GROUP, LLC

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  8

      No 

      • Repair the ground circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  8. REPLACE THE SPEED CONTROL SWITCH AND RETEST FOR DTCS 
    1. Replace the Speed Control Switch in accordance to the Service Information. Refer to SWITCH, SPEED CONTROL, REMOVAL AND INSTALLATION .
    2. Connect the Speed Control Switch and SCCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    3. With the scan tool, erase DTCs.
    4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    5. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • Replacing the Speed Control Switch corrected the fault
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
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