P0335: Crankshaft Position Sensor A Circuit Malfunction
Engine may not start, may stall during operation, rough idle, misfire, and reduced power due to lack of valid crankshaft position data
Overview
P0335 indicates a malfunction in the crankshaft position sensor A circuit where the engine control module is not receiving an acceptable signal from the crankshaft position sensor, leading to engine performance issues including no‑start, stalling, rough running, or misfires requiring diagnosis of sensor, wiring, tone ring, or control module.
Common Symptoms
- Check Engine Light illuminated
- Engine may not start or have difficulty starting
- Rough idle or misfire
- Stalling during driving or at idle
- Reduced acceleration and power
Most Common Causes
Primary and most frequent failure point when no valid signal is present
Circuit integrity issues often trigger P0335
Missing teeth or ring issues can prevent proper signal generation
Secondary engine mechanical cause that can disturb sensor timing
Rare cause after all other circuit and sensor issues are ruled out
Diagnostic Steps
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Connect OBD‑II scanner and confirm presence of P0335 and check for additional codesExpected: P0335 present; additional crank/cam related codes may appearInterpretation: Verifies code validity and helps identify related circuit faults
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Visually inspect crankshaft position sensor, wiring harness, and connector for damage, corrosion, or loose connectionExpected: No physical damage, secure connectorsInterpretation: Eliminate obvious circuit faults; damaged components may need repair
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Check sensor power supply and ground with multimeter per OEM specsExpected: Proper reference voltage and ground presentInterpretation: Confirms sensor is being powered and grounded correctly
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Measure sensor resistance or output waveform with oscilloscope while crankingExpected: Resistance within spec or valid square wave signal presentInterpretation: Determines sensor operability; invalid signal indicates sensor or tone ring issue
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Inspect reluctor (tone) ring for missing or damaged teethExpected: Evenly spaced uninterrupted ring teethInterpretation: Damaged ring leads to erratic signal triggering P0335
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If all above are normal, consider PCM testing or replacementExpected: No faults in external circuit; possible internal PCM faultInterpretation: PCM may be cause after exhaustive circuit diagnosis
Repair Solutions
Most common and direct fix for sensor failure
Essential if wiring integrity issues are found
More complex repair often requiring access under timing components
Timing component repair typically costly and labor intensive
Only after confirming circuit and sensor integrity
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Incorrect replacement of crankshaft position sensor without checking wiring/connectors or reluctor ring
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