P0342 code: Camshaft Position Sensor A Circuit Low
P0342 means camshaft Position Sensor A Circuit Low. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0342 means
The camshaft position sensor tells the computer where the valves are in their cycle, which it pairs with the crank signal to time fuel injection (and on many engines, to identify which cylinder is on its firing stroke). P0342 means the cam sensor's signal is reading LOW — stuck at or below its expected minimum — versus P0343, the same circuit reading high. Usual causes are a failed sensor, a wiring short to ground, a corroded connector, or a damaged reluctor on the cam; metal debris on the sensor's magnetic tip can also kill the signal. Many engines will still start and run on the crank sensor alone with a dead cam signal, but expect long cranking, rough running, or stalling — and on some engines a genuine no-start — so this sits in stalling/no-start territory and deserves prompt attention.
P0342 symptoms
- Hard starting or extended cranking
- Stalling or rough running
- Hesitation and reduced power
- Occasional no-start on some engines
- Check-engine light
What it costs to fix P0342
Typical range: $80–$300 · about ~0.2–1 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Camshaft position sensor | $30–$120 | ~0.2–1 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1.5 hrs |
Cam sensors usually mount accessibly on the cylinder head or timing cover, so this is one of the cheaper sensor replacements — often well under an hour. Costs climb only if a wiring fault needs tracing or the reluctor itself is damaged.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0342 for my exact vehicle →
How to fix P0342
Easy — basic tools, most owners can do this
- Inspect the cam sensor connector and wiring first
Unplug the camshaft position sensor and look for green corrosion, bent pins, or engine oil wicking into the connector — oil intrusion is a classic cause of a stuck-low signal. Follow the harness a hand-span in each direction for chafe marks where it crosses brackets or the valve cover. A wiring fault found here fixes the code for the cost of a connector cleaning.
- Rule out a weak battery
Low system voltage during cranking can drag sensor circuits below their minimum and set circuit-low codes as a side effect. If the battery is old or the car has been slow-cranking, load-test it before spending anything on parts — a marginal battery can produce a P0342 that has nothing to do with the sensor.
- Test the sensor’s signal
With a multimeter, check that the sensor is receiving its reference voltage (most modern hall-effect sensors get 5V or 12V) and ground. If a scan tool shows live data, compare the cam signal to the crank signal while cranking — a flatlined cam reading with a healthy crank reading points squarely at the sensor or its circuit.
- Replace the camshaft position sensor
On most engines the sensor is one bolt and one connector on the cylinder head or timing cover, and the part is inexpensive. Use an OEM or reputable brand — bargain-bin cam sensors have a high early-failure rate and can put you right back where you started.
- If the code returns, look deeper
A repeat P0342 after a new sensor means the problem is upstream: wiring shorted to ground between the sensor and the computer, a damaged tone ring/reluctor on the camshaft, or — on high-mileage engines — enough timing-chain wear to disturb the signal. This is the point to hand it to a shop with a scope.
DIY or shop? Connector checks, battery testing, and the sensor swap itself are genuinely DIY-friendly on most engines — the sensor is usually accessible and cheap. Go to a shop if the sensor is buried (some V6/V8 layouts), if wiring diagnosis is needed beyond a visual check, or if a new sensor didn’t fix it.
Tools for the DIY steps: Basic socket set · Multimeter · OBD-II scan tool with live data · Electrical contact cleaner
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0342.
Start a case with P0342 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0342?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0342: common questions
What does 'circuit low' mean on P0342?
The cam sensor's signal is flatlined at or below the minimum the computer expects — typically a dead sensor, a wire shorted to ground, or a connector problem. P0343 is the same circuit stuck high instead.
Will my car still start with P0342?
In many cases — many engines can start and run using the crank sensor alone, just with longer cranking and rougher running. Some engines, though, need the cam signal to start at all, so a no-start is possible depending on your vehicle.
Is P0342 the sensor or the timing chain?
A stuck-low signal is almost always electrical — sensor, wiring, or connector — rather than a timing problem. A stretched or jumped chain tends to set correlation codes (like P0016) or range/performance codes instead of a flatlined circuit.
How much does it cost to fix P0342?
Usually one of the cheaper sensor repairs — the part is inexpensive and most cam sensors are easy to reach on the head or timing cover, so many shops do it in under an hour. Wiring repairs add modestly once located.
What’s the difference between P0340 and P0342?
P0340 is the generic “cam sensor circuit malfunction” — the signal is wrong or missing in an unspecified way. P0342 is more specific: the signal is stuck LOW (flatlined at or below the minimum). P0343 is its mirror image, stuck high. The diagnosis path is nearly identical for all three; the low/high detail mostly hints at whether a short to ground (low) or a short to voltage (high) is in play.
Symptoms that trigger P0342
Drivers who get this code often notice one of these. Each has its own causes and cost guide:
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0342 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0342 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.