OBD-II Code P1345 — What It Means & How to Fix It

What Does This Error Mean?

P1345 is a GM-specific code indicating a Crankshaft Position (CKP) to Camshaft Position (CMP) correlation fault. The PCM compares the timing signals from the crankshaft and camshaft sensors. When those signals are too far out of sync, P1345 is set. This is very common on GM LS-based engines and often results from a distributor that is not timed correctly. Symptoms include rough idle, poor performance, and a check engine light.

Affected Models

Very common in Chevrolet Silverado and GMC Sierra with V8 engines
Common in Chevrolet Tahoe, Suburban, and Yukon
Common in Chevrolet Camaro and Corvette with LS engines
Common in Pontiac Firebird and GTO with LS-based engines

Common Causes

Distributor that has been installed or rotated out of the correct position
Jumped or worn timing chain causing the camshaft to lag behind the crankshaft
Faulty camshaft position sensor sending incorrect timing signals
Faulty crankshaft position sensor with erratic output
Wiring fault in the CMP or CKP sensor circuit causing signal corruption

How to Fix It

If any distributor work was recently performed, verify the distributor is in the correct position.

On Gen III and Gen IV GM V8s with a distributor, the rotor must point to the correct position at TDC on cylinder 1.
Connect a scan tool and check live CKP and CMP sensor data. Both should produce stable signals at idle.

Erratic or missing signal on one sensor while the other reads normally points to a faulty sensor.
Inspect the timing chain for stretch or wear. On high-mileage engines, the chain can skip a tooth causing cam-to-crank misalignment.

A stretched timing chain often causes P1345 alongside rough idle and reduced performance.
Check the wiring harness and connectors for both the CMP and CKP sensors. Look for damage, corrosion, or pinched wires.

The CKP sensor on GM V8s is often located near the front of the engine block and can be damaged by road debris.
Replace the faulty sensor (CMP or CKP) after confirming which one is generating the incorrect signal.

After replacement, clear the code and perform a complete drive cycle to confirm the fault does not return.

When to Call a Professional

Distributor adjustment is a DIY job if you are comfortable with basic engine timing. Timing chain replacement is $400 to $1,200 at a shop depending on the engine. Camshaft or crankshaft sensor replacement is $50 to $150 each. Improper distributor timing can damage the engine — if unsure, use a professional.

Frequently Asked Questions

Is P1345 the same as P0016?

They describe a similar fault — cam-to-crank correlation — but P1345 is GM-specific and P0016 is a generic OBD-II code. On GM vehicles P1345 is the manufacturer version of this fault. Both codes mean the cam and crank timing signals are out of sync.

Can I fix P1345 myself on my GM truck?

Possibly. If the distributor is the cause, proper reinstallation requires basic tools and a timing light or scan tool. If a stretched timing chain is the cause, that is a more involved repair requiring engine disassembly. Sensor replacement is straightforward for a home mechanic.

Will P1345 cause my truck to fail emissions?

Yes. P1345 triggers the check engine light, which automatically fails emissions in most states. The cam-to-crank correlation monitors must also complete and pass for emissions readiness.