Quick answer: The P0337 code indicates that the Powertrain Control Module (PCM) is receiving a lower-than-expected voltage signal from Crankshaft Position Sensor “A” or its circuit. This affects the engine ignition and timing system. It is a high-priority issue that frequently leads to sudden stalling or a no-start condition.
If your check engine light came on alongside engine stalling or trouble starting, your OBD-II scanner might display code P0337. This diagnostic trouble code points directly to an electrical signal failure within your crankshaft position sensor circuit. In this guide, we will break down what causes this code, how to spot the symptoms, and the proper steps to fix it.
What Does P0337 Mean?
The crankshaft position sensor monitors the rotation speed and precise position of the engine crankshaft, transmitting this essential data to the Powertrain Control Module (PCM). The PCM uses this signal to calculate precise spark plug ignition timing and fuel injection timing. When code P0337 is set, it means the PCM detected that the signal voltage coming from Crankshaft Position Sensor “A” fell below a predetermined threshold. Without an accurate timing signal, the engine computer cannot synchronize combustion properly.
Symptoms
- Engine cranks continuously but fails to start
- Engine stalls unexpectedly while driving or at stoplights
- Rough idling, engine misfires, or severe hesitation during acceleration
- Check Engine Light illuminated on the instrument cluster
- Loss of overall engine power and poor fuel economy
Possible Causes
Replacing the sensor immediately is a common mistake; damaged wiring, corrosion, or loose connectors are frequently the true cause of this circuit code.
- Damaged, corroded, or loose wiring harness and connectors in the sensor circuit
- Faulty or degraded crankshaft position sensor
- Low battery voltage causing power drops during engine cranking
- Damaged or contaminated reluctor ring (tone wheel) inside the engine
- Failed Powertrain Control Module or software issue (rare)
Check These Yourself Before Visiting a Mechanic
- Inspect the wiring harness leading to the crankshaft sensor for visible frays, melted insulation, or oil contamination.
- Ensure the electrical connector is pushed firmly onto the sensor and the locking clip is fully engaged.
- Check your car battery voltage with a multimeter to ensure it holds at least 12.6 volts when the engine is off.
How to Fix It
- Scan all vehicle control modules for related voltage or ignition system codes.
- Perform a thorough visual inspection of the crankshaft sensor wiring harness and repair any shorted or broken wires.
- Disconnect the sensor plug and inspect the terminals for corrosion, bent pins, or fluid ingress.
- Use a digital multimeter to test for proper reference voltage, ground signal, and continuity back to the PCM.
- Inspect the reluctor ring through the sensor port to ensure no teeth are bent, chipped, or covered in debris.
- Replace the crankshaft position sensor if electrical tests confirm the sensor itself has failed.
- Clear the diagnostic trouble codes and perform a test drive to verify normal engine operation.
Estimated Repair Costs (2026)
| Job | Parts ($) | Labor ($) |
|---|---|---|
| Crankshaft Position Sensor Replacement | $30 – $120 | $80 – $200 |
| Wiring Harness Repair / Connector Fix | $10 – $40 | $75 – $150 |
| Reluctor Ring Service / Replacement | $50 – $250 | $250 – $600 |
| PCM Diagnostics & Reprogramming | $100 – $300 | $100 – $200 |
Note: These estimates reflect typical 2026 US dollar rates. Actual repair costs vary based on vehicle make, model, and local shop labor fees.
Frequently Asked Questions
Can I drive with the P0337 code?
Driving with code P0337 is not recommended. Because the crankshaft signal directly dictates fuel and ignition timing, your engine may stall without warning in traffic, presenting a significant safety hazard.
How do I clear the P0337 code?
You can clear the code using an OBD-II scan tool after repairing the underlying fault. If the circuit fault or sensor failure is not resolved, the PCM will retrigger the code almost immediately upon starting the engine.
Can a weak battery trigger a P0337 code?
Yes, a weak or failing battery can cause significant voltage drops during engine cranking. If the system voltage drops too low while turning the engine over, the crankshaft sensor may fail to send a sufficient signal, triggering code P0337.