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Home >> Acura >> 2007 >> RL >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Electronic Throttle Control System >> DTC Troubleshooting >> DTC U0107: Lost Communication With Throttle Actuator Control Module
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DTC U0107: Lost Communication With Throttle Actuator Control Module

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
  1. Turn the ignition switch ON (II).
  2. Clear the DTC with the HDS.
  3. Check for Temporary DTCs or DTCs with the HDS.

    Is DTC U0107 indicated? 

    YES  - Check for, and repair any poor connections or loose terminals at the throttle body, the throttle actuator control module, and the PCM, then go to step  62. If the connections and terminals are OK, go to step  6.

    NO  - Go to step 4.

  4. Start the engine.
  5. Check for Temporary DTCs or DTCs with the HDS.

    Is DTC U0107 indicated? 

    YES  - Go to step  48.

    NO  - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the throttle body, the throttle actuator control module relay, the throttle actuator control module, and the PCM.

  6. Clear the DTC with the HDS.
  7. Turn the ignition switch OFF.
  8. Disconnect the intake air duct from the throttle body.
  9. Press the accelerator pedal to the floor.
  10. Turn the ignition switch ON (II).
  11. Check the throttle valve operation.

    Does the throttle valve open after it closes? 

    YES  - Go to step 12.

    NO  - Go to step  13.

  12. Check the throttle valve again.

    Does the throttle valve open fully? 

    YES  - Go to step  42.

    NO  - Go to step  36.

  13. Turn the ignition switch OFF.
  14. Disconnect the C251 connector (13P) between the PCM subharness and the throttle actuator control module subharness.
  15. Check for continuity between C251 connector (13P) terminal No. 7 and body ground.
    Fig 1: Checking Continuity Between C251 Connector (13P) Terminal No. 7 And Body Ground
    G05495129Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 16.

    NO  - Repair open in the wire between the C251 connector and G101, then go to step  63.

  16. Remove the throttle actuator control module relay (A).
    Fig 2: Identifying Throttle Actuator Control Module Relay
    G05495130Courtesy of AMERICAN HONDA MOTOR CO., INC.
  17. Measure voltage between throttle actuator control module relay 4P connector terminal No. 4 and body ground.
    Fig 3: Measuring Voltage Between Throttle Actuator Control Module Relay 4P Connector Terminal 4 And Body Ground
    G05495131Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  - Go to step  19.

    NO  - Go to step 18.

  18. Check the No. 1 THROTTLE ACTUATOR CONTROL (15A) fuse in the driver's under-dash fuse/relay box.

    Is the fuse OK? 

    YES  - Repair open in the wire between the throttle actuator control module relay (+B line) and the No. 1 THROTTLE ACTUATOR CONTROL (15A) fuse, then go to step  63.

    NO  - Repair short in the wire between the throttle actuator control module relay (+B line) and the No. 1 THROTTLE ACTUATOR CONTROL (15A) fuse, then go to step  63.

  19. Install the throttle actuator control module relay.
  20. Turn the ignition switch ON (II).
  21. Measure voltage between C251 connector (13P) terminal No. 12 and body ground.
    Fig 4: Measuring Voltage Between C251 Connector (13P) Terminal No. 12 And Body Ground
    G05495132Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage for about 2 seconds? 

    YES  - Go to step  52.

    NO  - Go to step 22.

  22. Turn the ignition switch OFF.
  23. Remove the throttle actuator control module relay (A).
    Fig 5: Identifying Throttle Actuator Control Module Relay
    G05495133Courtesy of AMERICAN HONDA MOTOR CO., INC.
  24. Check the throttle actuator control module relay (see POWER RELAY TEST ).

    Is the throttle actuator control module relay OK? 

    YES  - Go to step 25.

    NO  - Replace the throttle actuator control module relay, then go to step  63.

  25. Turn the ignition switch ON (II).
  26. Measure voltage between throttle actuator control module relay 4P connector terminal No. 2 and body ground.
    Fig 6: Measuring Voltage Between Throttle Actuator Control Module Relay 4P Connector Terminal 2 And Body Ground
    G05495134Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  - Go to step 27.

    NO  - Repair open in the wire between the throttle actuator control module relay and PGM-FI main relay 1 (Fl MAIN), then go to step  62.

  27. Turn the ignition switch OFF.
  28. Jump the SCS line with the HDS.
  29. Disconnect PCM connector E (31P).
  30. Check for continuity between PCM connector terminal E3 and throttle actuator control module relay 4P connector terminal No. 1.
    Fig 7: Checking Continuity Between PCM Connector Terminal E3 And Throttle Actuator Control Module Relay 4P Terminal 1
    G05495135Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 31.

    NO  - Repair open in the wire between the PCM (E3) and the throttle actuator control module relay, then go to step  63.

  31. Check for continuity between C251 connector (13P) terminal No. 12 and body ground.
    Fig 8: Checking Continuity Between C251 Connector (13P) Terminal No. 12 And Body Ground
    G05495136Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the throttle actuator control module and the throttle actuator control module relay (+B line), then go to step  63.

    NO  - Go to step 32.

  32. Check for continuity between throttle actuator control module relay 4P connector terminal No. 3 and C251 connector (13P) terminal No. 12.
    Fig 9: Checking Continuity Between Throttle Actuator Control Module Relay 4P Connector Terminal 3 And C251 (13P) Terminal 12
    G05495137Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 33.

    NO  - Repair open in the wire between the throttle actuator control module relay and the C251 connector (+B line), then go to step  63.

  33. Disconnect the throttle actuator control module 16P connector (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ).
  34. Check for continuity between C251 connector (13P) terminal No. 12 and body ground.
    Fig 10: Checking Continuity Between C251 Connector (13P) Terminal No. 12 And Body Ground
    G05495138Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

    NO  - Go to step 35.

  35. Check for continuity between throttle actuator control module 16P connector terminal No. 2 and C251 connector (13P) terminal No. 12.
    Fig 11: Checking Continuity Between Throttle Actuator Control Module 16P Terminal 2 And C251 (13P) Terminal 12
    G05495139Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step  68.

    NO  - Repair open in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

  36. Turn the ignition switch OFF.
  37. Jump the SCS line with the HDS.
  38. Disconnect the C251 connector (13P) between the PCM subharness and the throttle actuator control module subharness.
  39. Disconnect PCM connector A (31P).
  40. Check for continuity between PCM connector terminals A25 and body ground.
    Fig 12: Checking Continuity Between PCM Connector Terminals A25 And Body Ground
    G05495140Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the PCM (A25) and the C251 connector, then go to step  63.

    NO  - Go to step 41.

  41. Check for continuity between PCM connector terminal A25 and C251 connector (13P) terminal No. 11.
    Fig 13: Checking Continuity Between PCM Connector Terminal A25 And C251(13P) Terminal 11
    G05495141Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step  56.

    NO  - Repair open in the wire between the PCM (A25) and the C251 connector, then go to step  63.

  42. Turn the ignition switch OFF.
  43. Jump the SCS line with the HDS.
  44. Disconnect the C251 connector (13P) between the PCM subharness and the throttle actuator control module subharness.
  45. Disconnect PCM connector A (31P).
  46. Check for continuity between PCM connector terminal A26 and body ground.
    Fig 14: Checking Continuity Between PCM Connector Terminal A26 And Body Ground
    G05495142Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the PCM (A26) and the C251 connector, then go to step  63.

    NO  - Go to step 47.

  47. Check for continuity between PCM connector terminal A26 and C251 connector (13P) terminal No. 1.
    Fig 15: Checking Continuity Between PCM Connector Terminal A26 And C251 Connector (13P) Terminal No. 1
    G05495143Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step  59.

    NO  - Repair open in the wire between the PCM (A26) and the C251 connector, then go to step  63.

  48. Turn the ignition switch OFF.
  49. Jump the SCS line with the HDS.
  50. Disconnect PCM connectors A (31P) and B (24P).
  51. Check for continuity between body ground and PCM connector terminals A3 and B15 individually.
    Fig 16: Checking Continuity Between Body Ground And PCM Connector Terminals A3 And B15
    G05495144Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Check for poor connections or loose terminals at the throttle body, the throttle actuator control module relay, the throttle actuator control module, and the PCM, then go to step  1.

    NO  - Repair open in the wire between the PCM (A3, B15) and G101, then go to step  63.

  52. Disconnect the throttle actuator control module 16P connector (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ).
  53. Check for continuity between throttle actuator control module 16P connector terminal No. 7 and C251 connector (13P) terminal No. 7.
    Fig 17: Checking Continuity Between Throttle Actuator Control Module 16P Connector Terminal 7 And C251 (13P) Terminal 7
    G05495145Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 54.

    NO  - Repair open in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

  54. Check for continuity between C251 connector (13P) terminal No. 12 and body ground.
    Fig 18: Checking Continuity Between C251 Connector (13P) Terminal No. 12 And Body Ground
    G05495146Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

    NO  - Go to step 55.

  55. Check for continuity between throttle actuator control module 16P connector terminal No. 2 and C251 connector (13P) terminal No. 12.
    Fig 19: Checking Continuity Between Throttle Actuator Control Module 16P Connector Terminal 2 And C251 (13P) Terminal 12
    G05495147Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Substitute a known-good throttle actuator control module (see ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION  ), then go to step  63 and recheck. If DTC U0107 is not indicated, replace the original throttle actuator control module (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ), then go to step  63.

    NO  - Repair open in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

  56. Disconnect the throttle actuator control module 16P connector (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ).
  57. Check for continuity between C251 connector (13P) terminals No. 11 and body ground.
    Fig 20: Checking Continuity Between C251 Connector (13P) Terminals No. 11 And Body Ground
    G05495148Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

    NO  - Go to step 58.

  58. Check for continuity between throttle actuator control module 16P connector terminal No. 6 and C251 connector (13P) terminal No. 11.
    Fig 21: Checking Continuity Between Throttle Actuator Control Module 16P Connector Terminal 6 And C251 (13P) Terminal 11
    G05495149Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Substitute a known-good throttle actuator control module (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ), then go to step  63 and recheck. If DTC U0107 is not indicated, replace the original throttle actuator control module (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ), then go to step  63.

    NO  - Repair open in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

  59. Disconnect the throttle actuator control module 16P connector (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ).
  60. Check for continuity between C251 connector (13P) terminals No. 1 and body ground.
    Fig 22: Checking Continuity Between C251 Connector (13P) Terminals No. 1 And Body Ground
    G05495150Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

    NO  - Go to step 61.

  61. Check for continuity between throttle actuator control module 16P connector terminal No. 14 and C251 connector (13P) terminal No. 1.
    Fig 23: Checking Continuity Between Throttle Actuator Control Module 16P Terminal 14 And C251 (13P) Terminal 1
    G05495151Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Substitute a known-good throttle actuator control module (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ), then go to step  63 and recheck. If DTC U0107 is not indicated, replace the original throttle actuator control module (see THROTTLE ACTUATOR CONTROL MODULE REPLACEMENT  ), then go to step  63.

    NO  - Repair open in the wire between the throttle actuator control module and the C251 connector, then go to step  63.

  62. Turn the ignition switch OFF.
  63. Reconnect all connectors.
  64. Turn the ignition switch ON (II).
  65. Reset the PCM with the HDS.
  66. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  67. Check for Temporary DTCs or DTCs with the HDS.

    Is DTC U0107 indicated? 

    YES  - Check for poor connections or loose terminals at the throttle body, the throttle actuator control module relay, the throttle actuator control module, and the PCM, then go to step  1.

    NO  - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.

  68. Reconnect all connectors.
  69. Update the PCM if it does not have the latest software (see UPDATING THE PCM ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
  70. Check for Temporary DTCs or DTCs with the HDS.

    Is DTC U0107 indicated? 

    YES  - Check for poor connections or loose terminals at the throttle body, the throttle actuator control module relay, the throttle actuator control module, and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the PCM was substituted, go to step  1.

    NO  - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.

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