Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Testing
Left Side Object Sensor Malfunction
- Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B218L Side Object Sensor Module - Left. It may take up to 2 min for all vehicle systems to power down.
- Test for less than 10 Ω between ground circuit terminal 7 and ground.
- If 10 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- If less than 10 Ω
- Verify a test lamp illuminates between the B+ circuit terminal 8 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition Off.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the B218L Side Object Sensor Module - Left.
- If the test lamp illuminates
- Ignition OFF and all vehicle systems OFF.
- Test for less than 2 Ω between the B218L Side Object Sensor Module - Left serial data circuit terminal 1 and the X84 Data Link Connector serial data circuit terminal 1.
- If 2 Ω or greater
Repair the open/high resistance in the circuit.
- If less than 2 Ω
- If 2 Ω or greater
- Replace B218L Side Object Sensor Module - Left.
Side Object Indicator Malfunction
- Ignition OFF and all vehicle systems OFF, remove the appropriate outside rearview mirror glass. It may take up to 2 min for all vehicle systems to power down.
- Test for less than 10 Ω between the P34 Side Object Detection Indicator ground circuit terminal and ground.
- If 10 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- If less than 10 Ω
- Ignition ON, connect a test lamp between the P34 Side Object Detection Indicator control circuit terminal and ground.
- Verify the test lamp turns ON and OFF when commanding the Object Detection Alert Indicators ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the harness connector at the B218R Side Object Sensor Module - Right.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the B218R Side Object Sensor Module - Right.
- If the test lamp is always ON
- Ignition OFF, disconnect the harness connector at the B218R Side Object Sensor Module - Right, ignition ON.
- Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the B218R Side Object Sensor Module - Right.
- If the test lamp turns ON and OFF
- Test or replace the A9 Outside Rearview Mirror Glass.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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