Captiva

DTC B0091

The impact sensors are equipped on vehicles to supplement the Supplemental Inflatable Restraint (SIR) System performance. The impact sensors are electronic and are not part of the deployment loops, but instead provide inputs to the inflatable restraint sensing and diagnostic module (SDM). The impact sensors can assist in determining the severity of some frontal and side collisions. The SDM uses the input from the impact sensors to assist in determining the severity of a collision further supporting air bag deployment. If the SDM determines a deployment is warranted, the SDM will cause current to flow through the deployment loops deploying the appropriate air bags. The centre front impact sensor and side impact sensors utilise a bidirectional 2-wire circuit. The sensors modulate current on the interface to send identification, state of health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the sensors. When the ignition is turned ON and input power from the SDM is first detected, the sensors respond by performing internal diagnostics and sending an identification to the SDM. The SDM considers the identification to be valid if the response time is less than 5 seconds. The sensors continually communicate status messages to the SDM, which determines if a fault is present in the sensor circuit. When a fault is detected, the SDM may reset the sensors up to 2 times by removing and reapplying power to it. If the fault is still present, the SDM will set a DTC.

Ignition voltage is between 9-16 V.

B0091 01

The SDM has detected the centre front impact sensor has been shorted to voltage

B0091 02

B0091 04

B0091 39

B0091 3A

B0091 71

The SDM has received invalid serial data from the centre front impact sensor.

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

SIR System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. For DTC B0091 39, B0091 3A, B0091 71, replace the the B59 centre front impact sensor.
2. For DTC B0091 01, B0091 02, B0091 04, perform the Circuit/System Testing.

1. Ignition OFF, disconnect the X2 harness connector at the K36 SDM.
2. Test for infinite resistance between the signal circuit terminal 23 and ground.

⇒	If not the specified value, test the signal circuit for a short to ground.

3. Ignition ON, test for less than 1V between the signal circuit terminal 23 and ground.

⇒	If greater than the specified range, test the signal circuit for a short to voltage.

4. Ignition OFF, test for infinite resistance between the low reference circuit terminal 24 and ground.

⇒	If not the specified value, test the low reference circuit for a short to ground.

5. Ignition ON, test for less than 1V between the low reference circuit terminal 24 and ground.

⇒	If greater than the specified range, test the low reference circuit for a short to voltage.

6. Test for 1.8-5.5 Ω between signal circuit terminal 23 and low reference circuit terminal 24

⇒	If less than the specified range, replace the B59 centre front impact sensor

⇒	If greater than the specified range, test the signal circuit and low reference circuit for an open/high resistance. If the circuits test normal, replace the B59 centre front impact sensor

7. If all circuits test normal, replace the K36 SDM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.