Chevrolet P1345 Code: Crankshaft/Camshaft Position Correlation
The cam signal is out of step with the crank signal; on Vortec engines usually a mis-set distributor.
At a glance
Severity: Moderate
- Meaning
- Crankshaft/Camshaft Position Correlation
- System
- Ignition & Misfire · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $0–$1,400
- DIY difficulty
- Moderate
On Chevrolet Vortec 4.3L V6, 5.0L and 5.7L V8 and 7.4L V8 engines with a distributor (roughly the 1996–2002 trucks, vans and SUVs, and the 4.3L in later vans), the camshaft position sensor sits inside the distributor housing. The PCM compares its pulse with the crankshaft sensor and shows the offset as a 'cam retard' value; when that offset is too far from zero, P1345 sets. Turning the distributor on these engines doesn't change ignition timing, since the PCM controls spark, but it does move the cam signal and the rotor's alignment with the cap terminals. That's why a distributor installed or bumped a few degrees off both sets P1345 and can cause crossfire misfires inside the cap. A stretched or jumped timing chain produces the same code and is the reason not to adjust blindly.
Can I keep driving? Usually drivable, but if the engine misfires, backfires or runs rough, limit driving: crossfire and a stretched timing chain can both get worse quickly. If P1345 appeared right after distributor work, correct it before regular use.
How to read P1345
- P Powertrain
- 1 Manufacturer-specific
- 3 Ignition / misfire
- 45 Specific fault
Symptoms
- Check engine light, sometimes with no other symptom
- Misfire or stumble under load (spark jumping to the wrong cap terminal)
- Rough idle, occasional backfire through the intake
- Hard starting or long cranking
- Reduced power and fuel economy
- Rattle at cold start if the timing chain is stretched
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Distributor position (cam retard) out of the 0 ± 2 degree window, often after a cap, rotor or distributor replacement
- Stretched timing chain or worn cam gear changing cam-to-crank phasing
- Worn distributor shaft bushing or failing cam sensor (Hall pickup) inside the distributor
- Distributor installed one tooth off, or gear/shaft damage
- Crankshaft position sensor or its reluctor signal problem
- Wiring or connector fault on the cam or crank sensor circuit
Diagnosis step by step
Read the cam retard value
Connect a scan tool that shows GM enhanced data and find the cam retard (cam/crank offset) PID. Warm the engine and hold it above 1,000 rpm; the reading should be within 2 degrees of zero. A reading that is stable but well off zero means the distributor needs adjusting.
Tools: OBD-II scanner
Check whether the reading is stable
Watch the value for a minute at steady rpm. A value that wanders by several degrees suggests a worn distributor bushing, a failing cam sensor or a loose timing chain rather than a simple adjustment problem.
Tools: OBD-II scanner
Adjust the distributor
Loosen the distributor hold-down bolt slightly and rotate the housing a small amount while watching the cam retard reading: clockwise if it reads positive, counterclockwise if it reads negative, until it settles within ±2 degrees at 1,000+ rpm. Tighten the hold-down and recheck.
Tools: OBD-II scanner, Torque wrench
If it won't adjust into range
When the housing runs out of travel before the reading reaches zero, the distributor is likely a tooth off or the timing chain has stretched. Set the engine at top dead center on cylinder 1 and check the rotor position against GM's installation mark before going further.
Tools: Flashlight
Inspect cap, rotor and plug wires
Look inside the cap for carbon tracks and burn marks between terminals, a sign of crossfire that happened while the offset was wrong. Replace a scorched cap and rotor as a set.
Tools: Screwdriver
Check the timing chain
If the cam retard reading drifts or the engine has high mileage with a cold-start rattle, remove the distributor cap and rock the crankshaft back and forth; noticeable slack before the rotor moves indicates chain stretch.
Tools: Flashlight
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Set cam retard (distributor adjustment) | Yes | $0–$120 |
| Distributor cap and rotor | Yes | $40–$180 |
| Replace distributor assembly and set cam retard | Yes | $200–$550 |
| Crankshaft position sensor | No | $120–$320 |
| Timing chain and gears | No | $600–$1,400 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Emissions / smog test impact
Will fail
P1345 turns on the check engine light, so the vehicle fails a US OBD emissions test; any related misfire codes also have to be fixed and the monitors made ready again.
Frequently asked questions
Does turning the distributor change ignition timing on a Vortec?
No. On these engines the PCM controls spark timing from the crank sensor, so the distributor only changes the cam signal and rotor alignment. That's why you set it with a scan tool reading, not a timing light.
Why did P1345 appear right after I replaced the distributor?
New distributors are rarely installed exactly at the right position. You have to fine-tune the housing until the cam retard reading is within ±2 degrees; if you can't, it may be a tooth off.
Can I adjust cam retard with a basic code reader?
Usually not. You need a scan tool that displays GM enhanced data including cam retard. Some shops will set it for a small fee.
Can P1345 cause misfires?
Yes. With the distributor turned too far, the rotor tip can line up poorly with the cap terminals and the spark jumps to a neighboring terminal. That crossfire causes misfires and can scorch the cap.
Sources
- Manufacturer public service information (cross-checked)
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy