S-AWC (Super All Wheel Control)

DTC U1003: Bas-off
(Local CAN)

G AND YAW RATE SENSOR POWER SUPPLY

Refer to S-AWC (Super All Wheel Control).

CAUTION:

- If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
- Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
- Do not drop the G and yaw rate sensor or subject it to a shock.
- When G and yaw rate sensor is replaced, calibrate G and yaw rate sensor (refer to On-vehicle Service G and Yaw Rate Sensor Calibration ), and initialize the lateral/longitudinal acceleration correction amount stored in AWC-ECU. (Refer to item No.2: Lateral acceleration correction amount initialization, and No.3: Longitudinal acceleration correction amount initialization Actuator Test Reference Table .)

OPERATION

AWC-ECU communicates with ASC-ECU and G and yaw rate sensor via the local CAN.

DTC SET CONDITIONS

The code is set when local CAN ceases (bus-off).

PROBABLE CAUSES

- Malfunction of the CAN bus line (local)
- Malfunction of ASC-ECU
- Malfunction of G and yaw rate sensor
- Malfunction of AWC-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics

Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?

YES Go to Step 2.
NO Repair the CAN bus lines. CAN Bus Diagnostics Chart.)
STEP 2. Scan tool diagnostic trouble code

Check the ASC diagnostic trouble code. Active Stability Control System (ASC).)

Q. The diagnostic trouble code is set.

YES Perform the relevant troubleshooting.
NO Go to Step 3.
STEP 3. ASC-ECU connector, G and yaw rate sensor connector, AWC-ECU connector, intermediate connector, check: A-05, C-38, C-46, C-47

Q. Is the check result normal?

YES Go to Step 4.
NO Repair the defective connector. Then go to Step 7.
STEP 4. Check the wiring harness between C-46 AWC-ECU connector terminal No. 9, 10 and C-38 G and yaw rate sensor connector terminal No. 2, 3, and between C-46 AWC-ECU connector terminal No. 9, 10 and A-05 ASC-ECU connector terminal No. 18, 19.

Check the wiring harness for open and short circuit (to ground, to power supply, or line-to-line).

Q. Is the check result normal?

YES Go to Step 5.
NO Repair the wiring harness. Then go to Step 7.
STEP 5. Scan tool service data

Check the following service data. (Refer to Data List Reference Table.)

- Item No. 26: Yaw rate sensor
- Item No. 29: Lateral G sensor
- Item No. 31: Longitudinal G sensor

Q. Is the check result normal?

YES Go to Step 6.
NO Replace the G and yaw rate sensor. Service and Repair.) Then go to Step 6.
STEP 6. Check whether the diagnostic trouble code is reset.

Q. Is DTC No. U1003 set?

YES Replace the AWC-ECU.(Refer to Active Center Differential (ACD).) Then go to Step 7.
NO Intermittent malfunction. How to Cope With Intermittent Malfunctions.)
STEP 7. Check whether the DTC is reset.

Q. Is DTC No. U1003 set?

YES Return to Step 1.
NO This diagnosis is complete.