Light Does Not GO Out

SRS Warning Light Drive Circuit System Fault 1 (Light does not Go out.)

SRS Warning Light Drive Circuit:

CIRCUIT OPERATION
- Power for the SRS warning light is supplied from the ignition switch (IG1).
- The SRS warning light illuminates when the ignition switch is turned to the "ON" position and goes out after approximately seven seconds if there is not a malfunction in the SRS system.

DTC SET CONDITIONS
This DTC is set when a short to ground occurs in the harness between the SRS warning light and the SRS-ECU while SRS-ECU is monitoring the light and the light is ON. However, if the vehicle condition returns to normal, the DTC 43 will be automatically erased, and the SRS warning light will go out.

TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Malfunction of he SRS-ECU
- Malfunction of the combination meter

DIAGNOSIS

Required Special Tool:
- MB991502: Scan Tool (MUT-II)

STEP 1. Check SRS-ECU connector C-137 for damage.




1. Disconnect SRS-ECU connector C-137.




2. Check the short bar for the warning light inside the harness side connector for improper contact or deformation.

Q: Is SRS-ECU connector C-137 in good condition?

YES: Then go to Step 2.
NO: Repair or replace the SRS-ECU connector C-137. Then go to Step 4.

STEP 2. Check the SRS warning light.




1. Disconnect the SRS-ECU connector C-137.

CAUTION: Insert an insulator such as a cable tie to a depth of 4mm (0.16 inch) or more, otherwise the short bar will not be released.




2. Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick] between the terminals 3, 4 and the short bar to release the short bar.
3. Connect the negative battery cable.
4. Turn the ignition switch to the "ON" position.

Q: Does the SRS warning light go out?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 43 sets, replace the SRS-ECU. Then go to Step 4.
NO: Go to Step 3.







STEP 3: Check the harness wire for short circuit to ground between the SRS-ECU connector C-137 (terminal No.4) and the combination meter connector C-101 (terminal No.8).

Q: Is the harness wire between the SRS-ECU connector C-137 (terminal No.4) and the combination meter connector C-101 (terminal No.8) in good condition?

YES: Replace the combination meter. (Refer to Combination Meters Assembly and Vehicle Speed Sensor.) Then go to Step 4.
NO: Repair the harness wire between the SRS-ECU connector C-137 and the combination meter connector C-101. Then go to Step 4.

STEP 4. Check for DTC.

Q: Is DTC 43 set?

YES: Return to Step 1.
NO: The procedure is complete. (If no malfunctions are not found in all steps, an intermittent malfunction is suspected. Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction.)