HDS Does Not Communicate

Trans/Driveline

Real Time AWD Symptom Troubleshooting - HDS does not communicate

HDS does not communicate

NOTE: Before you troubleshoot, review the how to troubleshoot the real time AWD system.

1. 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 Testing and Inspection.

2. 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.

3. Fuse check:

-1. Turn the ignition switch to LOCK (0).

-2. Check the following fuse.






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.

4. 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.

5. Rear differential fluid pressure sensor check:

-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following 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 Rear Differential Fluid Pressure Sensor Removal And Installation.

6. Open wire check (IG1 P/W line):

-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.






-3. Start the engine.

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










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.

7. Open wire check (GND line):

-1. Turn the ignition switch to LOCK (0).

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










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.










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.

9. Open wire check (F CAN-H, F CAN-L lines):

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














Is there continuity?
-YES- Update the real time AWD control unit if it does not have the latest software Real Time AWD Control Unit Update, or substitute a known-good real time AWD control unit Service and Repair, 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 Service and Repair.
-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.