Left Rear Window Regulator Position Sensor Fault
The B0335 code means the vehicle's onboard diagnostic system has detected: Left Rear Window Regulator Position Sensor Fault. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $150 - $450 (parts and labor)

Basic scanners skip body codes entirely. BlueDriver reads airbag, HVAC, lighting, and BCM codes through your phone.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Common Symptoms
- Left Rear window does not operate
- Left Rear window moves slowly
- Window switch has no effect on left rear
- Left Rear window operates intermittently
Probable Causes (Ranked by Likelihood)
- Faulty left rear window motor Very High
- Failed window regulator assembly High
- Damaged wiring in left rear door Moderate
- Window switch failure Low
Step-by-Step Diagnostic Procedure
-
Test left rear window motor with direct power
-
Check window switch continuity
-
Inspect wiring through left rear door boot
-
Verify BCM window commands
Frequently Asked Questions
Why does my window go down but not up?
This often indicates a failing motor that has enough power to lower the window with gravity assistance but cannot raise it.
Can I raise the window manually?
Some regulators allow manual assist by pressing up while activating the switch, but this is a temporary measure.
Is the regulator and motor one assembly?
In many modern vehicles, the motor and regulator are sold as a single assembly for easier replacement.
Sources
This page is built from documented references. Verify against your own service info before repair work.
Explore More
Was this helpful?
Send this to whoever is fixing the car — your mechanic, or the person asking what the light means.