Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Impact sensor
- SDM module
- Impact sensor wiring harness connector
- SDM wiring harness connector
- Ignition OFF, disconnect the harness connector at the appropriate impact sensor.
- Disconnect the harness connector at the SDM.
- Ignition ON, test for less than 1 V between the following signal circuit and ground.
- Right front impact sensor terminal 1
- Left front impact sensor terminal 1
- Right front side impact sensor terminal B
- Left front side impact sensor terminal B
- Right rear side impact sensor terminal B
- Left rear side impact sensor terminal B
- If greater than the specified range, test the circuit for a short to voltage.
- Ignition ON, test for less than 1 V between the low reference circuit and ground.
- Right front impact sensor terminal 2
- Left front impact sensor terminal 2
- Right front side impact sensor terminal A
- Left front side impact sensor terminal A
- Right rear side impact sensor terminal A
- Left rear side impact sensor terminal A
- If greater than the specified range, test the circuit for a short to voltage.
- Test for infinite resistance between the signal circuit and ground.
- Right front impact sensor terminal 1
- Left front impact sensor terminal 1
- Right front side impact sensor terminal B
- Left front side impact sensor terminal B
- Right rear side impact sensor terminal B
- Left rear side impact sensor terminal B
- If less than the specified value, test the circuit for a short to ground.
- Test for less than 1 Ω between the following signal circuit terminals.
- Right front impact sensor terminal 1 and SDM terminal 26 X2.
- Left front impact sensor terminal 1 and SDM terminal 23 X2.
- Right front side impact sensor terminal B and the SDM terminal 22 X2.
- Left front side impact sensor terminal B and the SDM terminal 19 X2.
- Right rear side impact sensor terminal B and the SDM terminal 30 X2.
- Left rear side impact sensor terminal B and the SDM terminal 27 X2.
- If greater than the specified range, test the circuit for an open/high resistance.
- Test for less then 1 Ω between the following front end sensor low reference circuit terminals.
- Right front impact sensor terminal 2 and SDM terminal 25 X2.
- Left front impact sensor terminal 2 and SDM terminal 24 X2.
- Right front side impact sensor terminal A and the SDM terminal 21 X2.
- Left front side impact sensor terminal A and the SDM terminal 20 X2.
- Right rear side impact sensor terminal A and the SDM terminal 29 X2.
- Left rear side impact sensor terminal A and the SDM terminal 28 X2.
- If greater than the specified range, test the circuit for an open/high resistance.
- If all circuits test normal, replace the appropriate impact sensor.
- Reconnect all SIR components. Ignition ON, with a scan tool clear and check for DTCs.
- If the DTC returns and is current, replace the SDM.
NOTE:
Refer to SIR Service Precautions .
When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector: