Supplemental Restraint System (SRS)

DTC U1000: OSS-ECU CAN Time-out

CAUTION:

- If the DTC U1000 is set, diagnose the CAN bus lines.
- When replacing the ECU, always check that the SRS circuit is normal.

DIAGNOSTIC FUNCTION

If the signal from combination meter cannot be received, the SRS-ECU sets the diagnosis code No. U1000.

JUDGEMENT CRITERIA

Because of the CAN-B bus circuit malfunction, if SRS-ECU becomes unable to perform the normal data transmission, SRS-ECU determines that an abnormality is present.

TROUBLESHOOTING HINTS

- Malfunction of CAN bus line
- Malfunction of SRS-ECU
- Malfunction of the OSS-ECU

DIAGNOSIS

STEP 1. Using scan tool MB991958, diagnose the CAN bus line

(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958. Refer to "How to connect the scan tool Reading and Clearing Diagnostic Trouble Codes."

(2)Turn the ignition switch to the "ON" position.

(3)Diagnose the CAN bus line.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the CAN bus line found to be normal?

YES Go to Step 2.
NO Repair the CAN bus line CAN Bus Diagnostics Chart).
STEP 2. Using scan tool MB991958, read the OSS-ECU diagnostic trouble code

Check if the DTC is set to the OSS-ECU.

Q. Is the DTC set?

YES Diagnose the OSS. Then go to Step 4.
NO Go to Step 3.
STEP 3. Using scan tool MB991958, read diagnostic trouble code No.
U1000 for other system.

Check if the DTC U1000 is set in ETACS-ECU, occupant classification-ECU, combination meter, A/C-ECU, KOS-ECU or WCM, CAN box unit, radio and CD player, satellite radio tuner.

Q. Is the DTC set?

YES Replace the OSS-ECU Service and Repair).
NO Go to Step 4.
STEP 4. Recheck for diagnostic trouble code.

Check again if the DTC is set to the SRS-ECU.

(1)Erase the DTC.

(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.

(3)Check if DTC is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Replace the SRS-ECU.
NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).