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Home >> Nissan-Datsun >> 2012 >> Cube Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 89 (Climate Control) >> DTC Troubleshooting >> DTC B1241 or DTC indicator C and MODE: A Problem in the Blower Motor Circuit (Front)

DTC B1241 or DTC indicator C and MODE: A Problem in the Blower Motor Circuit (Front)

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.
  1. Clear the DTCs with the HDS.
  2. Turn the ignition switch to LOCK (0) and then back to ON (II).
  3. Do the self-diagnostic function with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS  ) or the climate control unit (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITHOUT THE HDS  ).
  4. Check for DTCs.

    Is DTC B1241 or C and MODE indicated? 

    YES  -Go to step 5.

    NO  -Intermittent failure, check for loose wires or poor connections in the front blower motor circuit.

  5. Turn the ignition switch to LOCK (0).
  6. Check the No. 12 (40 A) fuse in the relay block, and the No. 30 (10 A) fuse in the under-dash fuse/relay box.

    Are the fuses OK? 

    YES  -Go to step 7.

    NO  -Replace the fuse(s), and recheck. If fuse(s) blow again, check for a short in the No. 12 (40 A) and No. 30 (10 A) fuse(s) circuit.

  7. Connect front blower motor 2P connector terminal No. 2 to body ground with a jumper wire.
    Fig 1: Connecting Front Blower Motor 2P Connector Terminal No. 2 To Body Ground With Jumper Wire
    G08057892Courtesy of AMERICAN HONDA MOTOR CO., INC.
  8. Turn the ignition switch to ON (II).

    Does the front blower motor run at high speed? 

    YES  -Go to step 9.

    NO  -Go to step  24.

  9. Turn the ignition switch to LOCK (0).
  10. Disconnect the jumper wire.
  11. Disconnect the front power transistor 4P connector.
  12. Check for continuity between front power transistor 4P connector terminal No. 2 and body ground.
    Fig 2: Checking For Continuity Between Front Power Transistor 4P Connector Terminal No. 2 And Body Ground
    G08057893Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 13.

    NO  -Check for an open in the wire between the front power transistor and body ground. If the wire is OK, check for poor ground at G507 (see CONNECTOR TO FUSE/RELAY BOX INDEX ).

  13. Connect front power transistor 4P connector terminals No. 2 and No. 4 with a jumper wire.
    Fig 3: Connecting Front Power Transistor 4P Connector Terminals No. 2 And No. 4 With Jumper Wire
    G08057894Courtesy of AMERICAN HONDA MOTOR CO., INC.
  14. Turn the ignition switch to ON (II).

    Does the front blower motor run at high speed? 

    YES  -Go to step 15.

    NO  -Repair an open in the GRN wire between the front power transistor and the front blower motor.

  15. Turn the ignition switch to LOCK (0).
  16. Disconnect the jumper wire.
  17. Disconnect climate control unit connector A (40P).
  18. Check for continuity between body ground and climate control unit connector A (40P) terminals No. 9 and No. 10 individually.
    Fig 4: Checking For Continuity Between Body Ground And Climate Control Unit Connector A (40P) Terminals No. 9 And No. 10
    G08057895Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short to body ground in the wire(s) between the climate control unit and the front power transistor.

    NO  -Go to step 19.

  19. Check for continuity between the following terminals of climate control unit connector A (40P) and the front power transistor 4P connector.

    40P:

    No. 9

    No. 10

    4P:

    No. 3

    No. 1

    Fig 5: Checking For Continuity Between Terminals Of Climate Control Unit Connector A (40P) And Front Power Transistor 4P Connector
    G08057896Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 20.

    NO  -Repair an open in the wire(s) between the climate control unit and the front power transistor.

  20. Turn the ignition switch to ON (II).
  21. Measure the voltage between body ground and climate control unit connector A (40P) terminals No. 9 and No. 10 individually.
    Fig 6: Measuring Voltage Between Body Ground And Climate Control Unit Connector A (40P) Terminals No. 9 And No. 10
    G08057897Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there any voltage? 

    YES  -Repair a short to power in the wire(s).

    NO  -Go to step 22.

  22. Reconnect climate control unit connector A (40P).
  23. Test the front power transistor (see FRONT POWER TRANSISTOR TEST  ).

    Is the front power transistor OK? 

    YES  -Check for loose wires or poor connections at climate control unit connector A (40P) and at the front power transistor 4P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit (see CLIMATE CONTROL UNIT REMOVAL/INSTALLATION  ).

    NO  -Replace the front power transistor (see FRONT POWER TRANSISTOR TEST  ).

  24. Disconnect the jumper wire.
  25. Disconnect the front blower motor 2P connector.
  26. Measure the voltage between front blower motor 2P connector terminal No. 1 and body ground.
    Fig 7: Measuring Voltage Between Front Blower Motor 2P Connector Terminal No. 1 And Body Ground
    G08057898Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Replace the front blower motor (see BLOWER UNIT COMPONENT REPLACEMENT  ).

    NO  -Go to step 27.

  27. Turn the ignition switch to LOCK (0).
  28. Remove the front blower motor relay from the relay block, and test it (see POWER RELAY TEST ).

    Is the relay OK? 

    YES  -Go to step 29.

    NO  -Replace the front blower motor relay.

  29. Measure the voltage between front blower motor relay 4P socket terminal No. 1 and body ground.
    Fig 8: Measuring Voltage Between Front Blower Motor Relay 4P Socket Terminal No. 1 And Body Ground
    G08057899Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 30.

    NO  -Replace the under-hood fuse/relay box (see DTC B1065: RELAY CONTROL MODULE LOST COMMUNICATION WITH DRIVER'S MPCS UNIT (DRLOCKSW MESSAGE) ).

  30. Turn the ignition switch to ON (II).
  31. Measure the voltage between front blower motor relay 4P socket terminal No. 4 and body ground.
    Fig 9: Measuring Voltage Between Front Blower Motor Relay 4P Socket Terminal No. 4 And Body Ground
    G08057900Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 32.

    NO  -Repair an open in the wire between the No. 30 (10 A) fuse in the under-dash fuse/relay box and the front blower motor relay.

  32. Turn the ignition switch to LOCK (0).
  33. Check for continuity between front blower motor relay 4P socket terminal No. 3 and body ground.
    Fig 10: Checking For Continuity Between Front Blower Motor Relay 4P Socket Terminal No. 3 And Body Ground
    G08057901Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair an open in the WHT wire between the front blower motor relay and the blower motor.

    NO  -Check for an open in the wire between the front blower motor relay and body ground. If the wire is OK, check for poor ground at G202 (see CONNECTOR TO FUSE/RELAY BOX INDEX ).