Crankshaft Position Sensor A Circuit Low Input
The engine control module detects a low voltage signal from the crankshaft position sensor.
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What it means (plain English)
The crankshaft position sensor tracks the position of the crankshaft. If it sends a low voltage signal, it indicates either a fault in the sensor, the wiring, or the computer's ability to read the signal.
What the computer is actually seeing
The engine control unit expects a signal voltage around 0.5 to 5 volts from the crankshaft position sensor; a reading below 0.5 volts indicates a problem.
What a healthy reading looks like
0.5 to 5 volts from the crankshaft position sensor, typically around 2.5 volts at idle when everything is normal.
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 of the crankshaft position sensor for damage or corrosion. If found, repair or replace as needed. Decision Point: If wiring is good, proceed to step 2. If wiring is bad, fix and retest.
- 22. Test the crankshaft position sensor signal output with a multimeter. A healthy sensor should output between 0.5 to 5 volts while cranking. Decision Point: If voltage is within range, proceed to step 3. If it's low or nonexistent, replace the sensor and retest.
- 33. Check the crankshaft position sensor alignment and mounting. Misalignment can cause erratic readings. Decision Point: If alignment is off, adjust. If it’s aligned correctly, further diagnostics on the ECM may be needed.
Common causes
- Faulty crankshaft position sensor
- Damaged wiring or connector for the sensor
- Faulty engine control module (ECM)
- Poor ground connection
- Oil or debris contamination on the sensor
Typical repair cost
$$ (100 - 400)
Related codes
Frequently asked questions
Is it safe to drive with a P0337 code?
It depends. You may experience rough idling and stalling, so it's best to address it soon.
Will this issue come back after clearing the code?
If the underlying problem isn't fixed, the code will likely reappear.
Why might this code pair with other codes?
Multiple codes can indicate related issues, such as problems with other sensors or wiring problems.
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