Wheel Speed Sensor Rear Left Circuit Open
Indicates an open circuit in the rear left wheel speed sensor.
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)
The rear left wheel speed sensor isn't sending a signal because the wire is broken or disconnected, so the computer doesn't know how fast that wheel is spinning.
What the computer is actually seeing
The computer expects a voltage signal from the rear left wheel speed sensor, usually around 0-5 volts. If it sees no voltage, it throws the C1277 code.
What a healthy reading looks like
0-5 volts from wheel speed sensor; typically around 2.5 volts at rest.
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.
- 11. Inspect the wiring and connector from the rear left wheel speed sensor for damage or corrosion. If damaged, repair or replace as necessary.
- 22. Measure the voltage at the rear left wheel speed sensor connector with the ignition on. Expected value is 0-5 volts. If no voltage, go to step 3; if voltage is present, replace the sensor.
- 33. Check for continuity in the sensor wiring from the connector back to the ECM. If no continuity, repair the harness as needed; if continuity is good, replace the wheel speed sensor.
Common causes
- Broken wire in the harness
- Corroded or damaged connector
- Faulty wheel speed sensor
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderately safe, but may affect ABS and traction control functionality. Fix soon.
Will this code return after clearing?
Yes, if the underlying issue isn't fixed, the code will likely return.
Why does this code appear alongside other wheel speed sensor codes?
Multiple wheel speed sensor issues can occur due to shared wiring or similar failures.
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