B1335
Door Ajar RR Circuit Failure
Body Chassis/Safety Door sensors 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

Your rear-right door sensor is sending a bad signal to the car's computer, like a light switch that's stuck and won't report whether the door is open or closed. The ECU can't trust the door status reading and sets a fault code.

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Symptoms You May Notice
3 known symptoms for this code
Door ajar warning light stays on continuously
Interior lights don't turn off or behave erratically
Security system may not arm/disarm properly
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the door ajar switch circuit voltage on the rear-right door. The switch should toggle between open (high voltage) and closed (low voltage/ground) states when the door opens or closes. A circuit failure means the signal is stuck, shorted, or disconnected.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Door switch signal voltage 0V (closed) or 12V (open) Stuck voltage, no state change, or open circuit
Signal continuity Continuous switch response Intermittent or no signal detected
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Door ajar switch connector
Clean the connector pins on the rear-right door switch with electrical contact cleaner to remove corrosion.
2
Door ajar switch wiring harness
Inspect the wiring for cuts, pinches, or loose connections between the door and body; reseat any loose connectors.
3
Door ajar switch
Replace the faulty switch on the rear-right door latch mechanism if connector and wiring test good.