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Scan Tool Does Not Communicate With Class 2 Device: Testing

WARNING: This page is about a different car, the 2000 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tool to Data Link Connector (DLC) located under steering column. If scan tool powers up, go to next step. If scan tool does not power up, go to SCAN TOOL DOES NOT POWER UP .
  2. Turn ignition on. Attempt to communicate with following systems.
    • Powertrain Control Module (PCM)
    • Traction Control System (TCS)
    • Real Time Damping (RTD)
    • Body Control Module (BCM)
    • Instrument Panel Cluster (IPC)
    • Radio
    • Heater, Ventilation and Air Conditioning (HVAC)
    • Left Door Control Module (LDCM)
    • Right Door Control Module (RDCM)
    • Seat Control Module (SCM)
    • Remote Function Actuation (RFA)
    • Sensing and Diagnostic Module (SDM)

    If scan tool communicates with these systems, go to next step. If scan tool does not communicate with all systems, go to step  5.

  3. Check for communication DTCs (communication DTCs begin with "U"). If any DTCs between U1000 and U1255 are set, go to next step. If no DTCs are set, go to DIAGNOSTIC AIDS .
  4. If any system has communication DTCs U1000 or U1255 stored as current or history, go to DTC U1000 & U1255: CLASS 2 COMMUNICATION MALFUNCTION  under DIAGNOSTIC TESTS. If any system has communication DTCs U1001 through U1254 stored as current or history, go to DTC U1001-U1254: LOSS OF COMMUNICATION WITH XXX  under DIAGNOSTIC TESTS.
  5. Turn ignition off. Disconnect scan tool. Check for poor connections at DLC connector terminals No. 2 (Purple wire) and No. 5 (Black/White wire). See Figure. If connections are okay, go to next step. If faulty connections are found, repair as necessary and go to diagnostic system check for module or system not communicating.
  6. Check continuity in Black/White wire between DLC connector terminal No. 5 and ground. If circuit is okay, go to next step. If open circuit is found, repair as necessary and go to diagnostic system check for module or system not communicating.
  7. Disconnect bus bars from Black 12-pin star connectors No. 1 and 2. See COMPONENT LOCATIONS . Check for poor connections at star connectors. If connections are okay, go to next step. If faulty connections are found, repair as necessary and go to diagnostic system check for module or system not communicating.
  8. Turn ignition off. Disconnect scan tool. Ensure bus bars are still disconnected from star connectors No. 1 and 2. Using DVOM, check continuity of Purple wire between DLC connector terminal No. 2 and star connector No. 1 terminal "A". If continuity exists, go to next step. If continuity does not exist, repair as necessary and go to diagnostic system check for module or system not communicating.
  9. Turn ignition off. Connect scan tool. Ensure bus bars are still disconnected from star connectors No. 1 and 2. Connect Serial Data Link Tester (J-42236) to both star connectors. Ensure star connectors correctly correspond with serial data link testing connectors No. 1 and 2. Using serial data link tester, put switch in STAR CONNECTOR #1 position. Rotate rotary switch to "M" position. Turn ignition on. Using scan tool, attempt to establish communication with BCM. If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, go to step  12.
  10. Ensure switch on serial data link tester is in STAR CONNECTOR #1 position. Using scan tool, attempt to establish communication with the following vehicle systems by rotating rotary switch on serial data link tester as specified:

    • "L"

      Heating, Ventilation and Air Conditioning (HVAC) system (if equipped).

    • "J"

      Remote Function Actuator (RFA) system.

    • "H"

      Real Time Damping (RTD) system (if equipped).

    • "G"

      Instrument Panel Cluster (IPC).

    • "E"

      Traction Control System (TCS).

    • "D"

      Radio system.

    • "B"

      Powertrain Control Module (PCM).

    If scan tool communicates with each system, go to next step. If scan tool does not communicate with each system, go to step  12.

  11. Turn switch on serial data link tester to STAR CONNECTOR #2 position. Using scan tool, attempt to establish communication with the following vehicle systems by rotating rotary switch on serial data link tester as specified:

    • "C"

      Left Door Control Module (DCM) system.

    • "D"

      Right Door Control Module (DCM) system.

    • "K"

      Seat Control Module (SCM) system (if equipped).

    If scan tool does not communicate with each system, go to next step. If scan tool communicates with each system, go to step  15.

  12. Turn ignition off. Disconnect appropriate system module for system that did not communicate with scan tool. Using DVOM, check for short to ground or short to voltage in circuit between appropriate terminals on appropriate star connector and appropriate system module connectors. See SERIAL DATA LINE IDENTIFICATION  table. If circuits are okay, go to next step. If faulty circuit is found, repair as necessary and go to step  15.
  13. Check for poor connections at serial data line terminals for system that did not communicate with scan tool. If connections are okay, go to next step. If faulty connections are found, repair as necessary and go to step  15.
  14. Replace appropriate module for system that did not communicate with scan tool. After repairs, go to next step.
  15. Turn ignition off. Reinstall all components or connectors. Connect scan tool to DLC located under steering column. Turn ignition on. Wait 10 seconds for scan tool to power up. Display DTCs for each module. If any communication DTCs are set (communication DTCs begin with "U") and current, go to step  17. If no communication DTCs are set (communication DTCs begin with "U") or are set as history, go to next step.
  16. If any DTCs are set that do not begin with "U", go to next step. If no DTCs are set, go to step  19.
  17. Go to appropriate diagnostic and repair procedure for DTC under DIAGNOSTIC TESTS . If sent here from another article, return to that article and repair DTC under DIAGNOSTIC TESTS. After repairs, go to next step.
  18. If all DTCs are diagnosed and repaired, go to next step. If all DTCs are not diagnosed and repaired, go to step  17.
  19. Using scan tool, clear all DTCs.
SERIAL DATA LINE IDENTIFICATION

Star Terminal Wire Color Module (Terminal)
Star Connector No. 1
A Purple DLC (2)
B Dark Green PCM (C2, 58)
D Orange Radio (C2, 16)
E Light Blue EBTCM (10)
F Dark Blue SDM (A4)
G Gray IPC (A11)
H Dark Blue/White ESC (C2, D4)
J Pink RCDLR (D)
L White HVAC (D12)
Star Connector No. 2
A Purple DLC (2)
C Brown LDCM (C1, 3)
D Tan RDCM (C1, 3)
K Brown/White SCM (C1, 9)
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