Post Collision Diagnosis

To inspect and service the SRS after a collision (whether or not the air bags have deployed), perform the following steps.

SRS-ECU MEMORY CHECK




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

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector (16-pin).

NOTE: If the battery power supply has been disconnected or disrupted by the collision, scan tool MB991502 cannot communicate with the SRS-ECU. Check the battery then check and, if necessary, repair the front wiring harness and the body wiring harness before proceeding.

2. Read (and write down) all displayed diagnostic trouble codes.

Data List:

3. Read the data list (fault duration and how many times memories are erased) using scan tool MB991502.
4. Erase the diagnostic trouble codes and, after waiting five seconds or more, read (and write down) all displayed diagnostic trouble codes.

REPAIR PROCEDURE

WHEN FRONT AIR BAGS DEPLOY IN A COLLISION.
1. Replace the following parts with new ones.
- SRS-ECU
- Air bag module

2. Check the following parts and replace if there are any malfunctions.
- Clock spring
- Steering wheel, steering column and intermediate joint

1. Check the wiring harness (built into the steering wheel) and connectors for damage, and terminals for deformation.
2. Install the air bag module to check fit or alignment with the steering wheel.
3. Check the steering wheel for noise, binds or difficult operation and excessive free play.

3. Check the wiring harnesses for binding, the connectors for damage, poor connections, and the terminals for deformation.

WHEN AIR BAG DOES NOT DEPLOY IN LOW-SPEED COLLISION.
Check the SRS components. If the SRS components are showing any visible damage such as dents, cracks, or deformation, replace them with new ones. Concerning parts removed for inspection, replacement with new parts and cautionary points for working, refer to appropriate INDIVIDUAL COMPONENT SERVICE.




SRS-ECU
1. Check the SRS-ECU case and brackets for dents, cracks or deformation.
2. Check the connector for damage, and the terminals for deformation.




Air bag modules
1. Check the pad cover for dents, cracks or deformation.
2. Check the connector for damage, terminals deformities, and the harness for binding.
3. Check the air bag inflator case for dents, cracks or deformities.
4. Install the air bag module (driver's side) to the steering wheel to check fit or alignment with the steering wheel.
5. Install the air bag module (front passenger's side) to the instrument panel and crossmember to check fit or alignment.
6. Install the air bag module cover (front passenger's side) to the instrument panel to check fit or alignment.




Clock spring
1. Check the clock spring connectors and protective tube for damage, and the terminals for deformation.
2. Visually check the case for damage.

Steering wheel, steering column and intermediate joint
1. Check the wiring harness (built into the steering wheel) and the connectors for damage, and the terminals for deformation.
2. Install the air bag module to check fit or alignment with the steering wheel.
3. Check the steering wheel for noise, binding or difficult operation and excessive free play.

Harness connector (floor wiring harness)
Check the harnesses for binding, the connectors for damage, poor connection, and the terminals for deformation.