Left Rear Door Ajar Switch Circuit/Open
The left rear door ajar switch circuit is open or has a fault.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
There's a switch in the left rear door that tells the computer whether the door is open or closed, and it's not sending the correct signal.
What the computer is actually seeing
The Body Control Module (BCM) expects a low voltage (0-0.5V) when the door is closed and a high voltage (4.5-5V) when it’s open; it’s seeing an open circuit instead.
What a healthy reading looks like
Voltage at the door switch should be between 0V (door closed) and 5V (door open).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check the left rear door switch wiring and connectors for any visible damage or disconnections.
- 2Using a multimeter, check for voltage at the door ajar switch: should be ~0V when closed and ~5V when open.
- 3If the switch is functioning correctly, check the wiring harness for continuity between the switch and the BCM.
Common causes
- Faulty door ajar switch
- Broken wiring or connector issues
- BCM malfunction
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this error code?
Yes, it's drivable, but you may not have accurate door status alerts.
Will this issue come back after clearing the code?
It can return if there's a recurring fault with the switch or wiring.
Why do I see this code with B1640?
Both codes relate to door switches, and issues in one can affect the others.
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