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DTC 85: F-CAN Communication Failure

WARNING: This page is about a different car, the 2011 Acura TL, 2010 Acura TL, and 2009 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Check for fuel and emission systems DTCs with the HDS, and troubleshoot the PCM and F-CAN communication errors first (see GENERAL TROUBLESHOOTING INFORMATION )
  1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
  2. Clear the DTC with the HDS
  3. Turn the ignition switch to LOCK (0), then turn it to ON (II) again, or select the OFF mode, then the ON mode
  4. Wait about 5 seconds
  5. Check for DTCs with the HDS

    Is DTC 85 indicated? 

    YES  -Go to step 6

    NO  -The system is OK at this time

  6. Test-drive the vehicle

    Does the speedometer work? 

    YES  -Go to step  10

    NO  -Go to step 7

  7. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
  8. Disconnect the TPMS control unit 20P connector
  9. Test-drive the vehicle

    Does the speedometer work? 

    YES  -Check for loose terminals and poor connections at the TPMS control unit If necessary, substitute a known-good TPMS control unit (see TPMS CONTROL UNIT REPLACEMENT ), and recheck

    NO  -Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode, and reconnect all connectors, then check and troubleshoot the fuel and emissions systems (see GENERAL TROUBLESHOOTING INFORMATION )

  10. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
  11. Short the SCS line with the HDS
  12. Disconnect PCM connector A (49P)
  13. Disconnect the TPMS control unit 20P connector
  14. Check for continuity between the TPMS control unit 20P connector terminals and the PCM connector A (49P) terminals according to the table
    CONTINUITY REFERENCE CHART

    Terminal Name TPMS Control Unit 20P Connector Terminal PCM Connector A (49P) Terminal
    CANL No 11 No 49
    CANH No 2 No 48
    Fig 1: Checking Continuity Between TPMS Control Unit 20P Connector Terminals And PCM Connector A (49P) Terminals
    G05987865Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Check for loose terminals and poor connections at the TPMS control unit and G403 If necessary, substitute a known-good TPMS control unit (see TPMS CONTROL UNIT REPLACEMENT ), and recheck

    NO  -Repair open in the appropriate wire between the TPMS control unit and the PCM

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