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Home >> Acura >> 2009 >> RL >> Repair and Diagnosis >> Engine Performance >> System >> 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

CAUTION: Do not insert your fingers into the installed throttle body when you turn the ignition switch to ON (II) or while the ignition switch is ON (II). If you do, you will seriously injure your fingers if the throttle valve is activated.
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 to 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 to LOCK (0).
  8. Disconnect the intake air duct from the throttle body.
  9. Press the accelerator pedal to the floor.
  10. Turn the ignition switch to 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 to LOCK (0).
  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 For Continuity Between C251 Connector (13P) Terminal No. 7 And Body Ground
    G06164003Courtesy 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) from the passenger's under-dash fuse/relay box.
    Fig 2: Locating Throttle Actuator Control Module Relay
    G06164004Courtesy of AMERICAN HONDA MOTOR CO., INC.
  17. Measure the voltage between throttle actuator control module relay 4P connector terminal No. 1 and body ground.
    Fig 3: Measuring Voltage Between Throttle Actuator Control Module Relay 4P Connector Terminal No. 1 And Body Ground
    G06164005Courtesy 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 (15 A) 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 (15 A) 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 (15 A) fuse, then replace the fuse, and go to step  63.

  19. Install the throttle actuator control module relay.
  20. Turn the ignition switch to ON (II).
  21. Measure the 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
    G06164006Courtesy 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 to LOCK (0).
  23. Remove the throttle actuator control module relay (A) from the passenger's under-dash fuse/relay box.
    Fig 5: Locating Throttle Actuator Control Module Relay
    G06164007Courtesy 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 to ON (II).
  26. Measure the voltage between throttle actuator control module relay 4P connector terminal No. 4 and body ground.
    Fig 6: Measuring Voltage Between Throttle Actuator Control Module Relay 4P Connector Terminal No. 4 And Body Ground
    G06164008Courtesy 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 (FI MAIN), then go to step  62.

  27. Turn the ignition switch to LOCK (0).
  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. 3.
    Fig 7: Checking For Continuity Between PCM Connector Terminal E3 And Throttle Actuator Control Module Relay 4P Connector Terminal No. 3
    G06164009Courtesy 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 For Continuity Between C251 Connector (13P) Terminal No. 12 And Body Ground
    G06164010Courtesy 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. 2 and C251 connector (13P) terminal No. 12.
    Fig 9: Checking For Continuity Between Throttle Actuator Control Module Relay 4P Connector Terminal No. 2 And C251 Connector (13P) Terminal No. 12
    G06164011Courtesy 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 ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION ).
  34. Check for continuity between C251 connector (13P) terminal No. 12 and body ground.
    Fig 10: Checking For Continuity Between C251 Connector (13P) Terminal No. 12 And Body Ground
    G06164012Courtesy 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 For Continuity Between Throttle Actuator Control Module 16P Connector Terminal No. 2 And C251 Connector (13P) Terminal No. 12
    G06164013Courtesy 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 to LOCK (0).
  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 For Continuity Between PCM Connector Terminals A25 And Body Ground
    G06164014Courtesy 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 For Continuity Between PCM Connector Terminal A25 And C251 Connector (13P) Terminal No. 11
    G06164015Courtesy 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 to LOCK (0).
  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 For Continuity Between PCM Connector Terminal A26 And Body Ground
    G06164016Courtesy 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 For Continuity Between PCM Connector Terminal A26 And C251 Connector (13P) Terminal No. 1
    G06164017Courtesy 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 to LOCK (0).
  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 For Continuity Between Body Ground And PCM Connector Terminals A3 And B15 Individually
    G06164018Courtesy 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 ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION ).
  53. Check for continuity between throttle actuator control module 16P connector terminal No. 7 and C251 connector (13P) terminal No. 7.
    Fig 17: Checking For Continuity Between Throttle Actuator Control Module 16P Connector Terminal No. 7 And C251 Connector (13P) Terminal No. 7
    G06164019Courtesy 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 For Continuity Between C251 Connector (13P) Terminal No. 12 And Body Ground
    G06164020Courtesy 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 For Continuity Between Throttle Actuator Control Module 16P Connector Terminal No. 2 And C251 Connector (13P) Terminal No. 12
    G06164021Courtesy 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 ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION ), 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 ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION ).
  57. Check for continuity between C251 connector (13P) terminals No. 11 and body ground.
    Fig 20: Checking For Continuity Between C251 Connector (13P) Terminals No. 11 And Body Ground
    G06164022Courtesy 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 For Continuity Between Throttle Actuator Control Module 16P Connector Terminal No. 6 And C251 Connector (13P) Terminal No. 11
    G06164023Courtesy 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 ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION ), 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 ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION ).
  60. Check for continuity between C251 connector (13P) terminals No. 1 and body ground.
    Fig 22: Checking For Continuity Between C251 Connector (13P) Terminals No. 1 And Body Ground
    G06164024Courtesy 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. Hand C251 connector (13P) terminal No. 1.
    Fig 23: Checking For Continuity Between Throttle Actuator Control Module 16P Connector Terminal No. Hand C251 Connector (13P) Terminal No. 1
    G06164025Courtesy 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 ACCELERATOR PEDAL MODULE REMOVAL/INSTALLATION ), 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 to LOCK (0).
  63. Reconnect all connectors.
  64. Turn the ignition switch to 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 DTC's troubleshooting.

  68. Reconnect all connectors.
  69. Update the PCM if it does not have the latest software (see PCM UPDATE ), 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 DTC's troubleshooting.

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