OBD-II trouble code
P0342: Camshaft Position Sensor "A" Circuit Low (Bank 1 or Single Sensor)
SAE J2012: Camshaft Position Sensor "A" Circuit Low (Bank 1 or Single Sensor). The signal is below the expected range. The chart for this sensor says whether that is a short to ground, an open, or a failed sensor. Some engines keep running on the crankshaft signal. Some do not.
Quick facts
- System
- Powertrain
- Category
- Sensors / Timing
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $200 – $400 (camshaft position sensor replacement)
- DIY difficulty
- Intermediate DIY
Browse every code in P0300–P0394, or start from the full code library.
What does P0342 mean?
The camshaft position (CMP) sensor tells the PCM where the camshaft is in its rotation, which the engine uses to identify which cylinder is on its compression stroke for sequential fuel injection and to support variable valve timing. P0342 is the 'circuit low input' member of the CMP-A family on bank 1: the voltage the PCM reads on that circuit stays below the expected range. That's an electrical level complaint — distinct from P0340 (general circuit fault), P0341 (range/performance), P0343 (level too high), and P0344 (intermittent).
A low reading typically points to the circuit rather than the camshaft hardware. Common causes are a short to ground in the signal wire, an open or high-resistance connection, a corroded or loose connector, and a sensor that has failed and can no longer drive the circuit normally. On powered (three-wire) cam sensors, a lost supply voltage or a bad ground will also pull the output low. An excessive air gap reduces output amplitude on a two-wire variable-reluctance pickup, and oil from a leaking seal can wick into the connector and along the harness and corrode the terminals, which is why an oil leak is worth fixing when one is present rather than only fitting a new sensor.
The practical effect is usually milder than a crankshaft fault. Many engines fall back on the crankshaft signal to keep running, so the symptom is often a long crank or hard start (while the PCM works out cam timing), an occasional stumble, slightly reduced power, or disabled variable valve timing rather than a complete no-start. Some vehicles will still no-start if they rely on the cam signal for initial sync. Either way it should be fixed, since degraded sync hurts driveability and emissions. Diagnosis starts at the connector: check supply and ground on a powered sensor, test the signal wire for a short to ground or an open, inspect for oil intrusion and corrosion, and verify the sensor's output before replacing it.
Common causes
- Short to ground in the CMP signal wire pulling the circuit low
- Open circuit or high resistance collapsing the signal level
- Corroded or loose connector at the sensor
- Failed CMP sensor unable to drive the circuit normally
- Lost supply voltage or bad ground on a powered (three-wire) sensor
- Oil wicking into the connector or along the harness from a leaking seal and corroding the terminals; ferrous debris carried in dirty oil can also collect on the sensor tip
- Excessive air gap, or a sensor not seated against its mounting face — which reduces output amplitude on a two-wire variable-reluctance pickup
Symptoms
- Check engine light with P0342 stored
- Long crank or hard start
- Occasional stumble, hesitation, or reduced power
- Variable valve timing disabled, with slightly rougher running
- Intermittent no-start on vehicles that rely on the cam signal for sync
- Slightly reduced fuel economy
Diagnostic steps
- 1.Inspect the CMP sensor connector for corrosion, looseness, and oil intrusion — cam sensors often sit in oily areas, so contamination is common.
- 2.On a powered sensor, verify supply voltage and ground at the connector before testing the signal.
- 3.Check the signal wire for a short to ground and for opens or high resistance back to the PCM.
- 4.Scope or meter the sensor output during cranking; a level that stays below spec confirms the low-input condition. Before anyone cranks, route the leads clear of the belt, pulleys and cooling fan and keep hands and sleeves out of them — the engine may fire rather than just turn over.
- 5.Check the air gap and look for sludge or oil on the sensor tip that would weaken the signal.
- 6.Replace the sensor only after wiring, connector, supply, and ground all check out. Then perform any camshaft-position relearn the service information lists. RepairPal notes that an oil or coolant leak onto the sensor should be fixed with the part, or the new sensor fails the same way.
Repair cost
$200 – $400 (camshaft position sensor replacement)
Camshaft position sensor replacement, parts plus labor. This $200–$400 range is that sensor replacement. RepairPal's national average for the camshaft position sensor is about $224–$326, and this span rounds that so a harder-access sensor still fits. Wiring or a connector can cost less and is not this sensor price. An oil leak that would ruin the new sensor is its own job. RepairPal also says to perform any camshaft-position relearn the service information lists after replacement.
Estimate your repair
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Open the Repair Cost Estimator with camshaft position sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.