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OnStar Control Unit Input Test

  1. Remove the center console (see CENTER CONSOLE REMOVAL/INSTALLATION ).
  2. Disconnect the 22P and 16P connectors (A) from the OnStar control unit (B).
    Fig 1: Disconnecting 22P And 16P Connectors From OnStar Control Unit
    G03642656Courtesy of AMERICAN HONDA MOTOR CO., INC.
  3. Inspect the connector and socket terminals to be sure they are all making good contact.
    • If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
    • If the terminals look OK, go to step 4.
  4. Reconnect the connectors to the OnStar control unit, and make these input tests at the connectors.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If all input tests prove the terminals look OK, go to step 5.
    ONSTAR CONTROL UNIT INPUT TEST (CONNECTORS RECONNECTED)

    Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained
    A12 BLK Under all conditions Check for voltage to ground: There should be 1 V or less.
    • Poor ground (G502)
    • An open in the wire
    A1 RED/BLU Under all conditions Check for voltage to ground: There should be battery voltage.
    1. Blown No. 6 (10 A) fuse in the passenger's under-dash fuse/ relay box
    2. An open in the wire
    A2 YEL/GRN Ignition switch ON (II) Check for voltage to ground: There should be battery voltage.
    1. Blown No. 7 (7.5 A) fuse in the driver's under-dash fuse/relay box
    2. An open in the wire
    A13 WHT/RED Ignition switch in ACC (I) and ON (II) Check for voltage to ground: There should be battery voltage.
    1. Blown No. 8 (7.5 A) fuse in the driver's under-dash fuse/relay box
    2. Blown No. 9 (15 A) fuse in the passenger's under-dash fuse/ relay box
    3. Blown No. 54 (40 A) fuse in the under-hood fuse/relay box
    4. Faulty accessory power socket relay
    5. An open in the wire
    B10 GRY Under all conditions Check for voltage to ground: There should be 1 V or less.
    1. Poor ground (G502)
    2. An open in the wire
    B13 LTGRN/BLK Under all conditions Check for voltage to ground: There should be 1 V or less.
    1. Poor ground (G502)
    2. An open in the wire
    B14 BRN Under all conditions Check for voltage to ground: There should be 1 V or less.
    1. Poor ground (G502)
    2. An open in the wire
    B1 WHT Ignition switch in ACC (I) and ON (II) Check for voltage to ground: There should be about 4 V. Short in wire (0V)/ open in wire (8 V)
    1. Faulty OnStar button/ microphone assembly
    2. Faulty OnStar control unit
    Ignition switch in ACC (I) or ON (II), speak to the microphone at various volumes Check for voltage to B9: There should be about 0.1 to 0.9 V (A.C.) as you speak.
    1. Open or short in the wire
    2. Faulty OnStar button/ microphone assembly
    B9 BLU/RED Under all conditions Check for voltage to ground: There should be 1 V or less.
    1. Poor ground (G502)
    2. An open in the wire
    Unplug the OnStar button and microphone assembly Check for continuity to ground: There should be continuity.
    1. Poor ground (G502)
    2. An open in the wire
  5. Disconnect the 22P and 16P connectors from the OnStar control unit, and make these input tests at the connectors.
    • If any test indicates a problem, find and correct the cause, then recheck the system.
    • If all the input tests prove OK, substitute a known-good control unit, then recheck the system. If problem is gone, replace the control unit.
    ONSTAR CONTROL UNIT INPUT TEST (22P AND 16P DISCONNECTED)

    Cavity Wire Test condition Test; Desired result Possible cause if result is not obtained
    A3 RED/WHT Under all conditions
    NOTE: Disconnect the HandsFreeLink control unit 22P connector and audio unit connector F (14P)(2) or connector B{16P)(1)
    		 Check for continuity between the A3 terminal and HandsFreeLink control unit 22P connector No. 14 terminal: There should be continuity. An open in the wire
    Check for continuity to A12:
    There should be no continuity.    		 A short to ground
    B4 RED/BLU Check for continuity between the B4 terminal and HandsFreeLink control unit 22P connector No. 7 terminal and audio unit connector F(14P) No. 3 terminal(2) or connector B (16P) No. 4 terminal(1): There should be continuity. An open in the wire
    Check for continuity to A12: There should be no continuity. A short to ground
    B12 YEL Check for continuity between the B12 terminal and HandsFreeLink control unit 22P connector No. 19 terminal: There should be continuity. An open in the wire
    A10 RED/YEL Combination light switch in PARK position Check for voltage to ground: There should be battery voltage.
    1. Faulty combination light switch
    2. Faulty taillight relay
    3. An open in the wire
    A11 LTGRN/BLU Under all conditions Attach to ground: The horn should sound.
    1. Faulty horn
    2. Faulty horn relay
    3. An open in the wire
    A14 RED/GRN Under all conditions
    NOTE: Disconnect the SRS unit connector A (28P).
    		 Check for continuity between the A14 terminal and SRS unit 28P connector No. 21 terminal: There should be continuity. An open in the wire
    Check for continuity to A12: There should be no continuity. A short to ground
    A21 BLK/BLU Under all conditions
    NOTE: Disconnect the passenger's under-dash fuse/ relay box connector E (20P).
    		 Check for continuity between the A21 terminal and passenger's under-dash fuse/ relay box connector E (20P) No. 3 terminal: There should be continuity. An open in the wire
    Check for continuity to A12: There should be no continuity. A short to ground
    A22 ORN Check for continuity between the A21 terminal and passenger's under-dash fuse/ relay box connector E (20P) No. 7 terminal: There should be continuity. An open in the wire
    Check for continuity to A12: There should be no continuity. A short to ground
    B6 YEL/GRN Under all conditions Measure resistance between the B6 and B14 terminals: There should be about 4 k Ω.
    1. Faulty roof console
    2. An open in the wire
    B14 BRN
    B16 LTGRN Under all conditions NOTE: Disconnect the audio unit connector E (5P). Check for continuity between the B18 terminal and audio unit connector E (5P) No. 1 terminal: There should be continuity. An open in the wire
    Check for continuity to A12: There should be no continuity. A short to ground
    (1) Without Rear Entertainment System
    (2) With Rear Entertainment System
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