OBD-II Code P0340 — What It Means & How to Fix It

What Does This Error Mean?

P0340 means your car's computer is not receiving a signal from the camshaft position sensor. This sensor tells the computer where the camshaft is in its rotation cycle. Without this signal, the computer can't time fuel injection properly. Your car may not start at all, or it may stall, run very rough, or lose significant power. This is a critical code — get it fixed immediately as it can leave you stranded.

Affected Models

All vehicles 1996+
Common in Nissan Altima
Common in Jeep Grand Cherokee
Common in Dodge Caravan
Common in Chevrolet Trailblazer

Common Causes

Failed camshaft position sensor that has stopped producing a signal
Damaged or corroded wiring between the sensor and engine computer
Cracked or broken reluctor ring on the camshaft that triggers the sensor
Jumped timing chain or belt causing the camshaft to be out of position
Failed engine computer (ECM) not receiving the sensor signal properly

How to Fix It

Locate the camshaft position sensor on your engine. It's typically mounted on the cylinder head or valve cover near the front or top of the engine, held in by one bolt.

Search your vehicle's year, make, and model plus 'camshaft sensor location' for a visual guide.
Check the wiring connector at the sensor. Unplug it and inspect for corroded pins, water intrusion, or damaged wires. Oil leaks from the valve cover can contaminate the connector.

On many vehicles, a leaking valve cover gasket drips oil right onto the camshaft sensor connector.
Replace the camshaft position sensor. This is the most common fix for P0340 and is usually a simple one-bolt job. Make sure to match the exact part number for your vehicle.

Camshaft position sensors cost $15-$60. Installation usually takes 15-30 minutes with basic tools.
Check for oil contamination in the sensor connector. If oil has leaked into the plug, clean it thoroughly with electrical cleaner. Fix the oil leak (usually a valve cover gasket) to prevent recurrence.

A valve cover gasket replacement costs $20-$50 for parts and is a good weekend DIY project.
If the code persists after sensor replacement, listen for unusual rattling or ticking from the engine. This could indicate a timing chain or belt issue that's causing the camshaft to be out of proper position.

DO NOT drive the car if you suspect a timing problem. A jumped timing belt can bend valves and cause thousands of dollars in damage.

When to Call a Professional

If a new sensor and wiring check don't fix the code, you need professional help immediately. A jumped timing belt or chain can cause catastrophic engine damage if you keep driving. A mechanic can verify timing alignment and check for internal engine damage. Expect to pay $100-$200 for diagnosis. Repairs range from $50 for a sensor to $2,000+ for timing belt/chain replacement.

Frequently Asked Questions

Can P0340 cause my car not to start?

Yes, absolutely. The camshaft sensor is critical for starting on many vehicles. Without its signal, the computer doesn't know when to fire the injectors. Some cars will still crank and eventually start using backup strategies. Others will crank but never start at all.

Is P0340 serious?

Yes, this is a critical code. It can cause your car to stall unexpectedly in traffic. It can prevent your car from starting at all. If the root cause is a jumped timing belt, continued driving can destroy the engine. Don't delay this repair — address it immediately.

What is the difference between P0340 and P0341?

P0340 means no signal at all from the camshaft sensor. P0341 means the sensor is sending a signal, but the readings are out of range. P0340 is usually a dead sensor or broken wire. P0341 is more likely a timing issue or intermittent sensor problem. Both need prompt attention, but P0340 is more likely to leave you stranded.