What Does P1345 Mean?
P1345 indicates a malfunction in the camshaft position sensor (SGC sensor) circuit or a failure in the correlation between the crankshaft position and camshaft position signals. This is a common code on GM vehicles (particularly Vortec engines) where the distributor houses the CMP sensor. When the CMP signal does not align with the expected crankshaft reference, the ECU sets this code.
Safety Warning
Cam-crank correlation faults indicate a timing issue that can cause engine misfires, reduced power, and on interference engines, possible valve-to-piston contact. Diagnose before continued driving.
Common Causes
30%
Worn distributor gear causing camshaft-to-crankshaft timing drift (GM Vortec engines)
25%
Timing chain stretched or jumped a tooth
20%
Failed camshaft position sensor
15%
Distributor installed one tooth off from correct position
10%
Damaged wiring or connector to the CMP/SGC sensor
Diagnostic Steps
1
Use a scan tool to monitor the CKP-to-CMP correlation angle. Compare the learned value to the factory specification to determine if timing has drifted.
2
On distributor-equipped engines, remove the distributor cap and inspect the rotor alignment. Check the distributor gear for wear (common on Vortec 5.7L with nylon-lined gears).
3
Inspect the timing chain for excessive slack by removing the timing cover or using a scope through the oil fill. Check for chain rattle at idle.
4
Test the CMP sensor signal with an oscilloscope and verify it produces clean, correctly-timed pulses relative to the CKP signal.
5
If the distributor gear is worn, replace the distributor assembly. Ensure the rotor is aligned to the correct cylinder firing position during installation.
Estimated Repair Cost
$150 - $700
Parts + labor, varies by vehicle and location
P1345 indicates a malfunction in the camshaft position sensor (SGC sensor) circuit or a failure in the correlation between the crankshaft position and camshaft position signals. This is a common code on GM vehicles (particularly Vortec engines) where the distributor houses the CMP sensor. When the C...
The most common cause of P1345 (SGC (Cam Position) Sensor Circuit Malfunction/ Crankshaft Position - Camshaft Position Correlation) is: Worn distributor gear causing camshaft-to-crankshaft timing drift (GM Vortec engines)
Typical repair costs for P1345 range from $150 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Cam-crank correlation faults indicate a timing issue that can cause engine misfires, reduced power, and on interference engines, possible valve-to-piston contact. Diagnose before continued driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1345 to identify the root cause.
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Quick Info
Category
Powertrain
System
Valve Timing / Engine Position Sensing
Difficulty
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