What this code means

The PCM detected that the crankshaft position sensor and camshaft position sensor signals are not in proper correlation. This code is most common on Vortec V8 and V6 engines with distributors, particularly the 5.7L, 5.0L, and 4.3L. On distributor-equipped engines, this is often caused by a worn distributor gear or incorrect timing.

Symptoms

• Check Engine Light
• Engine misfires
• Sputtering and hesitation
• Loss of power
• Difficulty exceeding low speeds
• Stalling
• Rough idle
• Hard starting

Common causes

• Worn distributor gear or bearing
• Incorrect distributor timing
• Faulty CKP or CMP sensor
• Stretched timing chain
• Jumped timing
• Worn camshaft reluctor wheel

Diagnostic steps

1. Check distributor for excessive play or wear
2. Verify ignition timing with timing light
3. Test CKP and CMP sensor signals
4. Inspect timing chain for stretch
5. Compare cam and crank sensor waveforms with scope

Repair notes

On distributor-equipped engines (5.7L Vortec, 4.3L), check distributor gear and bearing first. Adjust distributor timing if equipped. On timing-chain engines, check chain stretch.

Other Powertrain codes on this vehicle