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DTC U1003: Bas-off (Local CAN)


G AND YAW RATE SENSOR POWER SUPPLY


Refer to .
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 GROUP 35C - On-vehicle Service ), 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 .)

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



DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting .)

STEP 2. Scan tool diagnostic trouble code
Check the ASC diagnostic trouble code. (Refer to GROUP 35C - Troubleshooting .)

Q. The diagnostic trouble code is set.
Perform the relevant troubleshooting.
Go to Step 3.

STEP 3. ASC-ECU connector, G and yaw rate sensor connector, AWC-ECU connector, intermediate connector, J/C (7) check: A-05, C-38, C-46, C-47, C-50

Q. Is the check result normal?
Go to Step 4.
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?
Go to Step 5.
Repair the wiring harness. Then go to Step 7.

STEP 5. Scan tool service data
Check the following service data. (Refer to .)

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

Q. Is the check result normal?
Go to Step 6.
Replace the G and yaw rate sensor. (Refer to GROUP 35C - G and Yaw Rate Sensor .) Then go to Step 6.

STEP 6. Check whether the diagnostic trouble code is reset.

Q. Is DTC No. U1003 set?
Replace the AWC-ECU.(Refer to .) Then go to Step 7.
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)

STEP 7. Check whether the DTC is reset.

Q. Is DTC No. U1003 set?
Return to Step 1.
This diagnosis is complete.