DTC 62

Driver's Air Bag Module (Squib) System Fault for Ground Circuit (Short-Circuited to Ground)

Driver's Air Bag Module (Squib) Circuit:

CIRCUIT OPERATION
- The SRS-ECU judges how severe a collision is by detecting signals from the front air bag analog G-sensor. If the impact is over a predetermined level, the SRS-ECU outputs an ignition signal. At this time, if the front air bag safing G-sensor is on, the SRS air bag will inflate.
- The ignition signal is input to the air bag module via the clock spring to inflate the air bag.

DTC SET CONDITIONS
- These DTC are output if there is abnormal resistance between the input terminals of the driver's air bag module (squib). However, if no DTC resets, the SRS warning light will be switched off (DTC will be retained).

TROUBLESHOOTING HINTS
- Malfunction of the clock spring
- Damaged harness wires and connectors
- Short to the ground in the driver's air bag module (squib) harness
- Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:
- MB991502: Scan Tool (MUT-II)
- MB991865: Dummy resister
- MB991866: Resister harness







STEP 1. Check the driver's air bag module.
1. By sliding the A section (in the figure) of air bag module connector C-201 in arrow direction, disconnect the connector.
2. Connect special tool MB991865 to special tool MB991866.

CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.

3. Insert special tool MB991866 into clock spring side air bag module connector C-201 by backprobing.
4. Connect the negative battery terminal.
5. Erase the DTC memory, any then recheck the DTC.

Q: Is DTC 62 output?

YES: Go to Step 2.
NO: Replace the driver's air bag module. Then go to Step 5.

STEP 2. Check the clock spring.
1. Disconnect two-pin clock spring connector C-205.




2. Connect special tool MB991865 to special tool MB991866.

CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.

3. Insert special tool MB991866 into clock spring harness side connector C-205 by backprobing.
4. Connect the negative battery terminal.
5. Erase the DTC memory, and then recheck the DTC.

Q: Is DTC 62 output?

YES: Go to Step 3.
NO: Replace the clock spring. Then go to Step 5.







STEP 3. Check the harness for short circuit to ground between the SRS-ECU and the clock spring.
Measurement at SRS-ECU connector C-12.
1. Disconnect SRS-ECU connector C-12.
2. Disconnect the clock spring connector C-205.
3. Measure at the wiring harness side.

CAUTION: Do not insert a test probe into the terminal from its front side directly as the connector contact pressure may be weakened.




4. Check the continuity between terminals 11,12 and body ground
- There should be open circuit.

Q: Is the continuity normal?

YES: Erase the DTC memory, and recheck if any DTC sets. If DTC 62 sets, replace the SRS-ECU. Then go to Step 5.
NO: Go to Step 5.







STEP 4. Check the harness for short circuit to ground between SRS-ECU connector C-12 and clock spring connector C-205.

Q: Are the harness wires between SRS-ECU connector C-12 and clock spring connector C-205 in good condition?

YES: Go to Step 5.
NO: Repair the harness wires between SRS-ECU connector C-12 and clock spring connector C-205. Then go to Step 5.

STEP 5. Check the DTC.

Q: Is DTC 62 output?

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