P0340 — Camshaft position sensor circuit malfunction
The camshaft position sensor signal is missing or implausible — can cause hard starts, stalling, or no-start.
What it means in plain English
P0340 is a camshaft position sensor circuit fault. The computer needs cam (and crank) signals for injection and ignition timing. Failures range from the sensor itself to wiring, tone rings, or related timing problems. Compare with P0335 (crank sensor).
Common causes
- Failed camshaft position sensor
- Wiring / connector faults
- Timing component issues affecting the signal
- Rarely, ECM input problems
What you can safely check
- Note intermittent no-start or stalling when hot.
- Inspect the connector if accessible without major disassembly.
Pull the code yourself (disclosed)
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A reusable Bluetooth OBD-II scanner lets you read the code and freeze-frame data before authorizing “mystery” diagnostics. One option: BlueDriver Bluetooth Pro OBD-II scan tool (BlueDriver/Levanta affiliate). Any capable OBD-II reader is fine — this is not required to use Fair Auto Shops.
When to go to a shop
Diagnosis should compare cam vs crank signals. Replacing sensors blindly when the timing chain has jumped wastes money.
Typical related repair costs (U.S. national averages)
These are related repairs shops may find after diagnosis — not a guaranteed bill for every P0340. Ranges exclude taxes, fees, diagnostics, and your location.
- $224–$326 national average for camshaft position sensor replacement (RepairPal; estimates last updated September 3, 2026; excludes taxes/fees and location; source). Labor $107–$157; parts $117–$169.
Related cost guides: Camshaft Position Sensor
Questions to ask before you authorize work
Use questions before you authorize a repair and how to read a repair estimate. Watch for patterns in spotting upselling.
Find an honest independent shop
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FAQ
What should I do first with a P0340 code?
Photograph all codes, note symptoms and whether the light is flashing, avoid clearing data until a shop sees it, then use an independent shop with a clear diagnostic plan.
More check-engine codes
P0420 · P0430 · P0300 · P0301 · P0171 · P0174 · P0455 · P0456 · P0442 · P0446 · P0128 · P0401 · P0133 · P0113 · P0506 · P0507 · P0700 · P0741 · P0011 · P0325 · P0335 · P0101 · P0299 · P0135 · P0440 · P0441 · P0010 · P0500 · P0121
Hub: How to read a check-engine code · Repair cost guides · Affiliate disclosure