OBD-II Code · Sensors
P0340
Camshaft Position Sensor Malfunction
Severity
critical
Highest on our scale. Expect major repair cost if it is ignored.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$150–$400
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
CMP sensor fault. Engine may not start or run rough.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- No start
- Check engine light
- Stalling
Likely causes
- Failed CMP sensorMost common
- Wiring issue
- Timing chain wear (advanced)
Read the full diagnostic procedureP0340 means the ECM is seeing no signal at all from the Bank 1 camshaft position sensor circuit, which on modern engines is the reference for variabl…
P0340 means the ECM is seeing no signal at all from the Bank 1 camshaft position sensor circuit, which on modern engines is the reference for variable valve timing closed-loop control and for sequential injection synchronization. On engines without a backup strategy, P0340 is a crank-no-start; on engines with limp-home logic, you get rough idle and a hot restart that takes 3-5 seconds longer than normal because the ECM has to find TDC the slow way.
Cheapest-first ladder
- scope the CMP signal during cranking and verify Hall-effect pattern (clean 0-5V square waves synced to crankshaft rotation at half speed).
- Unplug the connector and verify 5V reference and clean ground at the sensor with key on (anything less than 4.8V reference means an ECM-side feed problem, not a sensor problem).
- Inspect the cam reluctor target — on aluminum heads the target tooth can wear or get hit by a dropped valve spring keeper, and the tooth profile damage gives no-signal even with a good sensor.
- Check for oil intrusion into the CMP connector — chain-cover or cam-cover leaks routinely drown the CMP harness and pull the signal to ground through wet insulation.
Vehicle-specific patternsVW/Audi 2.0T EA888 and EA113 (2006-2015 GTI, A4, A5, Tiguan) sets P0340 when timing chain stretch lets the cam drift far enough out of crank correlat…
VW/Audi 2.0T EA888 and EA113 (2006-2015 GTI, A4, A5, Tiguan) sets P0340 when timing chain stretch lets the cam drift far enough out of crank correlation that the ECM disqualifies the CMP signal — the fix is a chain, tensioner, and guides job, not a sensor. Honda K-series K20/K24 (2002-2015 Civic Si, Accord, CR-V, Element, TSX) suffers Hall-effect CMP heat-aging failure where the sensor passes spec cold and goes no-signal after 30 minutes at operating temp — extremely common at 120k-180k miles.
- 2011-2018Chrysler 3.6 Pentastar throws P0340 when oil control valve screens clog with sludge from extended oil-change intervals and cam phasers cannot hold the commanded position, corrupting the CMP pattern. Ford 5.4 3V triton sets P0340 alongside P0016/P0017 when the cam phasers themselves fail mechanically.
Estimated repair$180 to $2400.
Look up another code
P0340 — frequently asked
What does a P0340 code mean?
CMP sensor fault. Engine may not start or run rough.
What causes a P0340 code?
Common causes: Failed CMP sensor; Wiring issue; Timing chain wear (advanced).
What are the symptoms of a P0340 code?
Typical symptoms: No start; Check engine light; Stalling.
Is it safe to drive with a P0340 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $150-$400.
How do I diagnose a P0340 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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