P0340 on the 6.0L Power Stroke is a camshaft position (CMP) sensor A circuit malfunction. The CMP sensor reads a target on the camshaft so the PCM knows engine position and can synchronize fuel injection. On the 6.0L the cam sensor is a primary timing input, and P0340 sets when the PCM does not receive a valid signal, which can cause hard starting, stalling, or a no-start.
The 6.0L relies on the camshaft signal to establish injection timing, and unlike some engines it does not always fall back cleanly to the crankshaft signal, so a cam sensor fault can leave you stranded. Fortunately the sensor is accessible and the circuit is simple, so P0340 is usually a quick diagnosis once you confirm whether the fault is the sensor, the wiring, or the tone wheel.
What P0340 means
The CMP sensor produces a signal as the camshaft turns, and the PCM uses it for engine synchronization. P0340 sets when that signal is missing, intermittent, or out of the expected electrical range. This points to the sensor, its wiring and connector, or the reluctor target on the camshaft rather than a mechanical timing problem inside the engine.
Common causes
- Failed camshaft position sensor
- Open, shorted, or chafed wiring in the sensor circuit
- Corroded or loose sensor connector
- Loss of reference or ground from the PCM
- Damaged camshaft target or debris on the sensor tip
Symptoms
- Hard starting or extended crank
- Stalling or intermittent no-start
- Rough running and hesitation
- Check engine light with P0340 stored
- Possible companion crankshaft correlation codes
How to diagnose it
Inspect the CMP sensor and connector for corrosion, a secure fit, and damage. With a scan tool, watch for a camshaft signal while cranking; no signal points to the sensor, wiring, or target. Check the sensor for power, ground, and a signal return, and verify the signal wire has continuity back to the PCM with no short. Remove the sensor and inspect the tip for debris. If power and ground are present but no signal is produced, the sensor or the target is at fault.
How to fix it
Repair open, shorted, or chafed wiring and clean or replace a corroded connector, which resolves many P0340 cases. If the wiring and reference are good but no valid signal is produced, replace the camshaft position sensor. Confirm the tip is clean and the target is undamaged. After the repair, clear the code, verify a valid cam signal while cranking, and confirm a normal start and road test. For the correct CMP sensor for your 6.0L Power Stroke, contact sales@coredieselparts.com.
Frequently asked questions
Will a 6.0L start with P0340?
Sometimes not. The cam signal is a primary timing input on the 6.0L, so a fault can cause a hard start or no-start. Repair it promptly to avoid being stranded.
Is P0340 the sensor or the wiring?
Both are common. Confirm the sensor has power and ground, then check for a signal while cranking. No signal with good power points to the sensor or target; a wiring fault shows as an open or short.
Can debris cause P0340?
Yes. Metal debris on the sensor tip can disrupt the signal. Inspect and clean the tip while checking the target for damage.
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