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Scan Tool Does Not Communicate With Cruise Control Module.

  1. Connect scan tool to Data Link Connector (DLC). Power up scan tool. If scan tool does not turn on, see SCAN TOOL INOPERATIVE  . If scan tool turns on, attempt to establish communication with cruise control module. If communication can not be established, go to next step.
  2. Attempt to establish communication with a like vehicle (model and year). If communication can be established, go to step 4). If communication cannot be established, go to next step.
  3. Ensure scan tool operates properly. If scan tool operation is okay, go to next step. If scan tool does not operate, see procedures in SCAN TOOL INOPERATIVE  .
  4. Disconnect cruise control module connector. Using a DVOM, measure resistance between cruise control module connector (harness side) terminal "H" (Brown/White wire) and DLC terminal No. 8 (Brown/White wire). See WIRING DIAGRAMS  . If resistance is less than 5 ohms, go to step 6). If resistance is 5 ohms or more, go to next step.
  5. Locate and repair open or high resistance in Brown/White wire between cruise control module and DLC. After repairs, go to step 15).
  6. Using a DVOM, measure resistance between DLC terminal No. 8 (Brown/White wire) and ground. See WIRING DIAGRAMS  . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step 10).
  7. Disconnect automatic level control sensor located on right side of rear differential. Using a DVOM, measure resistance between DLC terminal No. 8 (Brown/White wire) and ground. See WIRING DIAGRAMS  . If resistance is less than 5 ohms, go to step 9). If resistance is 5 ohms or more, go to next step.
  8. An internal failure within automatic level control sensor is pulling serial data circuit to ground. Replace automatic level control sensor. After repairs, go to step 15).
  9. If all control modules are disconnected and a short to ground still exists, locate and repair short to ground in suspect serial data circuit. After repairs, go to step 15).
  10. Using a DVOM, measure voltage between DLC terminal No. 8 (Brown/White wire) and ground. See WIRING DIAGRAMS  . If battery voltage is present, go to next step. If battery voltage is not present, go to step 14).
  11. Disconnect automatic level control sensor located on right side of rear differential. Using a DVOM, measure voltage between DLC terminal No. 8 (Brown/White wire) and ground. See WIRING DIAGRAMS  . If battery voltage is present, go to step 13). If battery voltage is not present, go to next step.
  12. An internal failure within automatic level control sensor is pulling serial data circuit to battery voltage. Replace automatic level control sensor. After repairs, go to step 15).
  13. If all control modules are disconnected and a short to battery voltage still exists, locate and repair short to voltage in suspect serial data circuit. After repairs, go to step 15).
  14. Using a DVOM, check cruise control module power and ground circuits. Repair as necessary. If power and ground circuits are okay, replace cruise control module. See CRUISE CONTROL MODULE  . After repairs, go to next step.
  15. Reconnect all connectors and components. Connect scan tool to DLC. Attempt to establish communication with cruise control module. If communication can not be established, go to step 1).
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