Real Time AWD System Symptom Troubleshooting - HDS does not communicate (AWD)

HDS does not communicate 

• 1. HDS communication check:

  - 1. Turn the vehicle to the ON mode.

  - 2. Check that the HDS communicates with the vehicle.

  Does the HDS communicate with the vehicle?

  YES 

  The HDS communication is OK. Go to step 2.

  NO 

  Go to the DLC circuit troubleshooting .

• 2. Real time AWD system communication check:

  - 1. Check the Main Menu of the REAL TIME AWD with the HDS.

  Does the HDS show the Main Menu of the REAL TIME AWD?

  YES 

  The real time AWD system communication is OK. Intermittent failure, the system is OK at this time.

  NO 

  Go to step 3.

• 3. Fuse check:

  - 1. Turn the vehicle to the OFF (LOCK) mode.

  - 2. Check the following fuse.

  Fuse	No. B6 (7.5 A)
  Location	Under-dash fuse/relay box

  Is the fuse OK?

  YES 

  The fuse is OK. Reinstall the fuse, then go to step 4.

  NO 

  Repair a short to ground in the No. B6 (7.5 A) fuse circuit.

• 4. Rear differential pump motor operation check:

  - 1. Turn the vehicle to the ON mode.

  - 2. Check the operation sound of the rear differential pump motor on the rear differential with a stethoscope or a flat-tipped screwdriver (at the rear differential pump motor) when the engine started.

  NOTE:  The rear differential pump motor operates within several seconds after the engine is started.

  Rear differential pump motor operation sound heard?

  YES 

  Repair an open in the F-CAN_H and/or F-CAN_L wires.

  NO 

  Go to step 5.

• 5. Rear differential fluid pressure sensor check:

  - 1. Turn the vehicle to the OFF (LOCK) mode.

  - 2. Disconnect the following connector.

  Rear differential fluid pressure sensor 3P connector

  - 3. Turn the vehicle to the ON mode.

  - 4. Check the Main Menu of the REAL TIME AWD with the HDS.

  Does the HDS show the Main Menu of the REAL TIME AWD?

  YES 

  The rear differential fluid pressure sensor is OK. Go to step 6.

  NO 

  Replace the rear differential fluid pressure sensor .

• 6. Open wire check (IG1 P/W line):

  - 1. Turn the vehicle to the OFF (LOCK) mode.

  - 2. Disconnect the following connector.

  Real time AWD control unit 24P connector

  - 3. Start the engine.

  - 4. Measure the voltage between test points 1 and 2.

  Test condition	Vehicle ON mode (idling)
  	Rear differential fluid pressure sensor 3P connector: disconnected
  	Real time AWD control unit 24P connector: disconnected
  Test point 1	Real time AWD control unit 24P connector No. 12
  Test point 2	Body ground

  Is there battery voltage?

  YES 

  The wire is OK. Go to step 7.

  NO 

  Repair an open in the wire between the real time AWD control unit and the No. B6 (7.5 A) fuse in the under-dash fuse/relay box.

• 7. Open wire check (GND line):

  - 1. Turn the vehicle to the OFF (LOCK) mode.

  - 2. Check for continuity between test points 1 and 2.

  Test condition	Vehicle OFF (LOCK) mode
  	Rear differential fluid pressure sensor 3P connector: disconnected
  	Real time AWD control unit 24P connector: disconnected
  Test point 1	Real time AWD control unit 24P connector No. 8
  Test point 2	Body ground

  Is there continuity?

  YES 

  The GND wire is OK. Go to step 8.

  NO 

  Repair an open in the GND wire between the real time AWD control unit and ground (G603).

• 8. Shorted wire check (SVCC line):

  - 1. Check for continuity between test points 1 and 2.

  Test condition	Vehicle OFF (LOCK) mode
  	Rear differential fluid pressure sensor 3P connector: disconnected
  	Real time AWD control unit 24P connector: disconnected
  Test point 1	Real time AWD control unit 24P connector No. 20
  Test point 2	Body ground

  Is there continuity?

  YES 

  Repair a short to ground in the SVCC wire between the real time AWD control unit and the rear differential fluid pressure sensor.

  NO 

  The SVCC wire is OK. Go to step 9.

• 9. Open wire check (F-CAN_H, F-CAN_L lines):

  - 1. Check for continuity between test points 1 and 2 individually.

  Test condition

  Vehicle OFF (LOCK) mode

  	Rear differential fluid pressure sensor 3P connector: disconnected
  	Real time AWD control unit 24P connector: disconnected
  Test point 1	Real time AWD control unit 24P connector No. 14
  Test point 2	DLC (16P) No. 6

  Test point 1	Real time AWD control unit 24P connector No. 24
  Test point 2	DLC (16P) No. 14

  Courtesy of HONDA, U.S.A., INC.

  Is there continuity?

  YES 

  Update the real time AWD control unit if it does not have the latest software , or substitute a known-good real time AWD control unit , and recheck. If the symptom/indication goes away with the updated real time AWD control unit, troubleshooting is complete. If the symptom/indication goes away with a known-good real time AWD control unit, replace the original real time AWD control unit .

  NO 

  Repair an open in the F-CAN_H and/or F-CAN_L wires between the real time AWD control unit and the DLC.