Cause
Damaged reluctor or tone ring
The toothed ring a speed or position sensor counts. A damaged or contaminated ring produces a faulty signal from a perfectly good sensor, which is why sensors get replaced twice on this fault.
A missing or bent tooth, or debris packed between them, reads exactly like sensor failure.
Typically specialist work. Needs equipment or training most home workshops do not have.
Some of these codes mean you should stop driving
20 of the 45 codes this can cause indicate a fault where continuing to drive risks damage or is unsafe. Which one you have matters more than the cause does — read the code's own page before deciding.
Codes this can cause (45)
Codes where this is a likely explanation first, rather than merely a possible one.
- C0030 Left Front Tone Wheel Likely for this code Moderate
- C0033 Right Front Tone Wheel Likely for this code Moderate
- C0036 Left Rear Tone Wheel Likely for this code Moderate
- C0039 Right Rear Tone Wheel Likely for this code Moderate
- C003C Rear Tone Wheel Likely for this code Moderate
- P0336 Crankshaft Position Sensor A Circuit Range/Performance Likely for this code Stop driving High
- P0370 Timing Reference High Resolution Signal A Likely for this code Stop driving High
- P0372 Timing Reference High Resolution Signal A Too Few Pulses Likely for this code Stop driving High
- P0373 Timing Reference High Resolution Signal A Intermittent or Erratic Pulses Likely for this code Stop driving High
- P0375 Timing Reference High Resolution Signal B Likely for this code Stop driving High
- P0377 Timing Reference High Resolution Signal B Too Few Pulses Likely for this code Stop driving High
- P0378 Timing Reference High Resolution Signal B Intermittent or Erratic Pulses Likely for this code Stop driving High
- P0386 Crankshaft Position Sensor B Circuit Range/Performance Likely for this code Stop driving High
- P0721 Output Shaft Speed Sensor Circuit Range/Performance Likely for this code High
- P215C Output Shaft Speed - Wheel Speed Correlation Likely for this code Moderate
- P2161 Vehicle Speed Sensor B Circuit Intermittent/Erratic/High Likely for this code High
- C0031 Left Front Wheel Speed Sensor Moderate
- C0034 Right Front Wheel Speed Sensor Moderate
- C0037 Left Rear Wheel Speed Sensor Moderate
- C003A Right Rear Wheel Speed Sensor Moderate
- C003D Rear Wheel Speed Sensor Moderate
- C006B Stability System Active Too Long Moderate
- C0078 Tyre Diameter Moderate
- P0315 Crankshaft Position System Variation Not Learned Moderate
- P0335 Crankshaft Position Sensor A Circuit Stop driving Critical
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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