HDS does not communicate

Fig 1: Real Time AWD System Symptom Troubleshooting (HDS Not Communicate)

Courtesy of AMERICAN HONDA MOTOR CO., INC.

NOTE: Before you troubleshoot, REVIEW THE HOW TO TROUBLESHOOT THE REAL TIME AWD SYSTEM .

HDS communication check:
- 1. Turn the ignition switch to ON (II).
- 2. Check that the HDS communicates with the vehicle.
Does the HDS communicate with the vehicle?

YES : Go to step 2.

NO : GO TO THE DLC CIRCUIT TROUBLESHOOTING .
Real time AWD system communication check:
- 1. Check the Main Menu of the real time AWD system with the HDS.
Does the HDS show the Main Menu of the real time AWD system?

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

NO : Go to step 3.
Fuse check:
- 1. Turn the ignition switch to LOCK (0).
- 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 in the No. B6 (7.5 A) fuse circuit.
Rear differential pump motor operation check:
- 1. Turn the ignition switch to ON (II).
- 2. Check the operation sound of the rear differential pump motor on the rear differential with a stethoscope or a flat-tip screwdriver (at the rear differential pump motor) when the engine is 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.
Rear differential fluid pressure sensor check:
- 1. Turn the ignition switch to LOCK (0).
- 2. Disconnect the following connector.
  Rear differential fluid pressure sensor 3P connector
- 3. Turn the ignition switch to ON (II).
- 4. Check the Main Menu of the real time AWD system with the HDS.
Does the HDS show the Main Menu of the real time AWD system?

YES : Go to step 6.

NO : REPLACE THE REAR DIFFERENTIAL FLUID PRESSURE SENSOR .
Open wire check (IG1 P/W line):
- 1. Turn the ignition switch to LOCK (0).
- 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 IG ON (II)
  
  Rear differential fluid pressure sensor 3P connector: disconnected
  
  Real time AWD control unit 24P connector: disconnected
  
  Test circuit IG1 P/W
  
  Test point 1 Real time AWD control unit 24P connector No. 12 (RED)
  
  Test point 2 Body ground
  
  Fig 2: Measuring Voltage Between Real Time AWD Control Unit 24P Connector No. 12 (Red) And Body Ground
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?

YES : The IG1 P/W wire is OK. Go to step 7.

NO : Repair an open in the IG1 P/W wire between the real time AWD control unit and the No. B6 (7.5 A) fuse in the under-dash fuse/relay box.
Open wire check (GND line):
- 1. Turn the ignition switch to LOCK (0).
- 2. Check for continuity between test points 1 and 2.
  Test condition IG LOCK (0)
  
  Rear differential fluid pressure sensor 3P connector: disconnected
  
  Real time AWD control unit 24P connector: disconnected
  
  Test circuit GND
  
  Test point 1 Real time AWD control unit 24P connector No. 8 (BLK)
  
  Test point 2 Body ground
  
  Fig 3: Checking Continuity Between Real Time AWD Control Unit 24P Connector No. 8 (BLK) And Body Ground
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
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).
Shorted wire check (SVCC line):
- 1. Check for continuity between test points 1 and 2.
  Test condition IG LOCK (0)
  
  Rear differential fluid pressure sensor 3P connector: disconnected
  
  Real time AWD control unit 24P connector: disconnected
  
  Test circuit SVCC
  
  Test point 1 Real time AWD control unit 24P connector No. 20 (WHT)
  
  Test point 2 Body ground
  
  Fig 4: Checking Continuity Between Real Time AWD Control Unit 24P Connector No. 20 (WHT) And Body Ground
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?

YES : Repair a short to ground in the SVCC wire between the real time AWD control unit and body ground.

NO : The SVCC wire is OK. Go to step 9.
Open wire check (F CAN-H, F CAN-L lines):
- 1. Check for continuity between test points 1 and 2.
  Test condition IG LOCK (0)
  
  Rear differential fluid pressure sensor 3P connector: disconnected
  
  Real time AWD control unit 24P connector: disconnected
  
  Test circuit F CAN-H
  
  Test point 1 Real time AWD control unit 24P connector No. 14 (WHT)
  
  Test point 2 DLC (16P) No. 6 (WHT)
  
  Test circuit F CAN-L
  
  Test point 1 Real time AWD control unit 24P connector No. 24 (RED)
  
  Test point 2 DLC (16P) No. 14 (RED)
  
  Fig 5: Checking Continuity Between Real Time AWD Control Unit 24P Connector No. 14 (WHT) And DLC (16P) No. 6 (WHT)
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?

YES : Update the real time AWD control unit if it does not have the latest software See REAL TIME AWD CONTROL UNIT REMOVAL AND INSTALLATION or REAL TIME AWD CONTROL UNIT UPDATE , or substitute a known-good real time AWD control unit See REAL TIME AWD CONTROL UNIT REMOVAL AND INSTALLATION or REAL TIME AWD CONTROL UNIT UPDATE , 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 See REAL TIME AWD CONTROL UNIT REMOVAL AND INSTALLATION or REAL TIME AWD CONTROL UNIT UPDATE .

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.