P1345
Crankshaft Position — Camshaft Position Correlation
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The P1345 code is one of the most common GM-specific trouble codes, especially on Vortec V8 and V6 engines from the late 1990s through 2000s. It means the PCM has detected that the crankshaft position sensor and camshaft position sensor signals are not aligned within the expected 1–2 degree tolerance window.
On older GM trucks and SUVs with distributor ignition, this code is most often caused by a distributor that has slipped or was installed incorrectly. The fix involves loosening the distributor hold-down bolt and rotating the distributor while watching sensor correlation on a scan tool. On newer engines without distributors, a stretched timing chain is a common cause.
This code should be addressed promptly because poor cam-crank correlation leads to incorrect ignition and fuel injection timing, which causes rough running, hard starts, and reduced power. While the vehicle may still be drivable, the longer you wait, the worse the driveability symptoms typically become. For distributor-equipped engines, this can be a quick and inexpensive fix if you have a scan tool.
Severity
Symptoms
- •Engine runs rough and may sputter at idle
- •Hard starting or extended cranking before the engine fires
- •Noticeable loss of power during acceleration
- •Engine may stall unexpectedly
- •Poor fuel economy
Likely Causes
On older GM engines with distributors (like the 5.7L Vortec), the distributor may have slipped or been installed incorrectly, putting the cam-crank correlation more than 2 degrees out of sync.
Over time the timing chain stretches, causing the camshaft and crankshaft signals to fall out of their expected correlation window of 1–2 degrees.
A failing CMP sensor can send erratic or delayed signals, making the PCM think the cam-crank relationship is out of spec even when mechanical timing is fine.
A degraded CKP sensor or a cracked/chipped reluctor ring on the crankshaft can produce inaccurate timing signals.
Corroded connectors or damaged wiring on either the CMP or CKP sensor circuits can introduce signal errors.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Adjust or reinstall the distributor to correct timing (older GM engines)
- Replace the camshaft position sensor
- Replace the crankshaft position sensor
- Replace a worn or stretched timing chain and gears
- Inspect and repair sensor wiring and connectors