OBD-II Code · Sensors
P0342
CMP Sensor A Low Input
Severity
high
Left alone, this one tends to take other parts with it.
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 voltage low.
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
- Check engine light
- No start
Likely causes
- Failed sensorMost common
- Wiring short
Read the full diagnostic procedureP0342 means the Bank 1 CMP signal voltage is stuck below the low-threshold limit — the sensor signal is shorted to ground, the sensor is dead with in…
P0342 means the Bank 1 CMP signal voltage is stuck below the low-threshold limit — the sensor signal is shorted to ground, the sensor is dead with internal short, or the signal wire has chafed against a grounded surface. The engine usually starts and runs because most modern ECMs can synthesize a fallback CMP from the crank signal alone, but you lose sequential injection precision and VVT goes open-loop.
Cheapest-first ladder
- unplug the CMP connector and key-on, then measure signal wire to ground at the harness side (should read 5V reference floating; if it reads 0V, the wire is shorted to ground upstream).
- Plug back in and recheck — if voltage now reads 0V, the sensor is internally shorted.
- Inspect the harness route between sensor and ECM for chafing against the valve cover, EGR pipe, or intake manifold bolts.
- Check for oil saturation of the connector from a leaking cam-cover gasket — wet electrical contacts read as a short to ground in 90% of cases.
- Verify 5V reference at the sensor connector (pin varies by platform; check service info) — a failed 5V regulator inside the ECM will pull all three reference circuits down and you will have P0342 alongside throttle and MAP codes.
Vehicle-specific patternsHonda K-series CMP at high mileage frequently fails low rather than open as the Hall IC degrades — bench-test will show a sensor that produces a stuc…
Honda K-series CMP at high mileage frequently fails low rather than open as the Hall IC degrades — bench-test will show a sensor that produces a stuck-low output instead of clean square waves. Ford 5.4 3V Triton sets P0342 alongside cam-correlation codes when a failed phaser also damages the CMP signal pattern. VW/Audi 2.0T EA888 sees P0342 from oil intrusion into the CMP connector when the cam adjuster gasket leaks (extremely common, gasket is $15). Nissan VQ35DE (Murano, 350Z, Altima) throws P0342 from valve-cover oil leaks soaking the CMP pigtail until the insulation breaks down.
Estimated repair$120 to $580.
Look up another code
P0342 — frequently asked
What does a P0342 code mean?
CMP voltage low.
What causes a P0342 code?
Common causes: Failed sensor; Wiring short.
What are the symptoms of a P0342 code?
Typical symptoms: Check engine light; No start.
Is it safe to drive with a P0342 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 P0342 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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