P0018: Crankshaft Position – Camshaft Position Correlation (Bank 2, Sensor A)
May cause rough idle, loss of power, poor fuel economy, engine hesitation or stalling when the timing correlation deteriorates beyond acceptable limits
Overview
P0018 indicates that the engine control module has detected an out-of-sync relationship between the crankshaft position signal and the Bank 2 camshaft position sensor A signal, often due to timing system, sensor, or VVT issues
Common Symptoms
- Illuminated check engine light
- Rough or uneven idle
- Reduced engine performance
- Increased fuel consumption
- Difficulty starting or stalling
Most Common Causes
Wear in timing components can allow the chain/belt to skip teeth, altering cam/crank correlation
CMP sensor failure or poor signal can trigger a correlation fault
CKP sensor signal errors disrupt timing correlation
VVT system issues can affect cam timing and trigger the code
Frayed, broken, or corroded wiring can cause intermittent signals
Loose, damaged, or sheared key on crank or cam tone rings impacts sensor readings
Diagnostic Steps
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Scan for P0018 and any accompanying codes with an OBD-II scannerExpected: Retrieves P0018 and possibly other timing/cam/crank related codesInterpretation: Presence of multiple timing codes may point toward systemic timing or VVT issues
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Visually inspect camshaft and crankshaft position sensors and harnessesExpected: No frayed wires, corrosion, or connector faultsInterpretation: Damaged wiring or connectors likely cause inconsistent signals
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Check sensor signal patterns with oscilloscope or multimeterExpected: Consistent, proper waveform signals for both cam and crank sensorsInterpretation: Missing or erratic signal indicates faulty sensor or tone ring issue
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Inspect timing chain/belt alignment and conditionExpected: Proper alignment with no skipped teeth or excessive slackInterpretation: Misaligned or worn timing components cause correlation error
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Test variable valve timing solenoid/actuator operationExpected: Proper function allowing cam phasing in and outInterpretation: Stuck/failed VVT components can trigger P0018
Repair Solutions
Labor intensive; recommended when mechanical timing misalignment is confirmed
Common if testing shows sensor signal faults
Necessary if VVT diagnostics indicate malfunction
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Replacing only the camshaft or crankshaft sensor without verifying timing component alignment or wiring integrity
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