B2877

Side Impact Sensor, Passenger





Fault symptoms
Airbag warning lamp on.

Conditions
The following conditions are applicable to the respective diagnostic trouble codes:

B2876
- No communication between side impact sensor and control module.

B2877
- The voltage on the side impact sensor's communications lead is lower than 3 V for 1.25 s.

B2878
- The voltage on the side impact sensor's ground lead is higher than 6 V for 1.25 s.

Diagnostic help
Diagnostic trouble code B2876 will be generated if the side impact sensor is defective or if the sensor's communications lead (pin 1 on the side impact sensor, pin 44 on the control module) is short-circuited to battery positive (B+) or open-circuit (broken).

Action

1. Check the wiring harness between the control module and the passenger's side impact sensor




- Turn the ignition switch to the OFF position.




- Undo the connector: Impact sensor, passenger door, front: (328P)




- Check and if necessary rectify pins 1 and 2 with respect to open circuit/pin slide-out.
- Undo the connector: Control Module Airbag: (331)
- Check and if necessary rectify pins 43 and 44 with respect to open circuit/pin slide-out.
- Connect a break-out box (BOB) to the mains.
- Take a resistance reading




- Red feed cable: Control module Airbag: 43




- Black feed cable: Impact sensor, passenger door, front:2
- The value should be 0 - 2 ohms

Test results OK?

YES
- Go to step2.
NO
- Repair or replace the wiring.
- Go to step5.

2. Check the wiring harness between the control module and the passenger's side impact sensor
- Take a resistance reading




- Red feed cable: Control module Airbag: 43




- Black test lead: Car battery: B-.
- The resistance should be infinite (O.L.).

Test results OK?

YES
- Go to step3.
NO
- Repair or replace the wiring.
- Go to step5.

3. Check the wiring harness between the control module and the passenger's side Impact sensor
- Take a resistance reading




- Red feed cable: Control module Airbag: 44




- Black feed cable: Impact sensor, passenger door, front:1
- The value should be 0 - 2 ohms

Test results OK?

YES
- Go to step4.
NO
- Repair or replace the wiring.
- Go to step5.

4. Check the wiring harness between the control module and the passenger's side impact sensor
- Take a resistance reading




- Red feed cable: Control module Airbag: 44




- Black test lead: Car battery: B-.
- The resistance should be infinite (O.L.).

Test results OK?

YES
- Change: Impact sensor, passenger door, front
- Go to step 5.
NO
- Repair or replace the wiring.
- Go to step 5.

5. Final check




- Clear the diagnostic trouble codes in all systems.
- Perform a driving cycle:
- Drive the car with varying engine loads and at varying engine speeds for five minutes.
- Evaluate the driving cycle:




- Check that the diagnostic trouble code has not recurred.

Test results OK?

YES
- The steps taken to rectify the fault were correct.
NO
- See before changing a control module.