This guide will cover everything you need to know about the common P0342 powertrain OBD2 code. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.
Camshaft Position Sensor Circuit Low Input
Camshaft’s position sensor signal is a critical signal for the engine to calculate ignition and fuel timings, and this is a code that will oftentimes throw your engine into emergency mode (low max rpms, capped power, just about enough for you to get to the garage). When this sensor isn’t working properly, the PCM cannot properly calculate the camshaft’s position (will get contradicting data from other sensors, truly). The PCM needs this information to make the calculations mentioned above, which are essential for the engine to perform properly.
A P0342 code is typically caused by one, or a combination of, the following causes:
- A poorly performing battery, either dead or low in charge.
- An issue in the wiring harness / electric circuit between sensor and PCM. This could increase the impedance of the circuit as a whole, throwing the signal off.
- A defective starter motor
- Any issues in the starting circuit
- A defective camshaft position sensor
Note we mentioned the most obvious one as the last possible cause. Too many mechanics will be eager and quick to replace very expensive components to beef up their billables, but this may in turn not end up fixing the issue. Obviously, if you’re working in your own car, you want to start by removing any other possibilities from the equation before settling for replacing the sensor.
The most obvious symptoms your car will show when you have a P0342, are:
- Check Engine Light on (duh)
- Capped RPMs (although not always, depends on the manufacturer)
- Inconsistent power curve (if you don’t hit emergency mode)
- Stalling (VERY common, particularly at low RPMs)
Note that there are many other issues that will present this kind of symptoms, and most of them will give you a P (powertrain) code of some sort.
Once you’ve done your DTC check with a scanner and are sure you’re working with a P0342 issue (don’t just assume based on symptoms, as covered above. Although you wouldn’t be reading this particular page if you were), here’s how to properly diagnose this and find the culprit:
- Check the battery condition with a multimeter. First with the engine off, which should give you at least over 12.5v. Then with the engine running, you should have between 13.7 and 14.7v. Any values below that are great candidates for a faulty battery.
- Check that you don’t have battery-related DTC codes too. Clean them if you do and run the engine again. If they appear again, battery’s gotta go.
- Inspect the connector, harness and all the wiring from sensor to PCM. Look for bent pins, corrossion, dirt… Clean if necessary and apply dielectric grease.
- If you’re using a manufacturer-specific scanner, or if you have the manual at hand, you may know the exact values the sensor should read when tested with a multimeter. Take it out and test.
- If nothing else comes with an issue, replace the camshaft position sensor.
A common mistake when diagnosing a P0342 is attibuting the issue directly to the sensor without testing.
Another common mistake, is to use inferior replacement parts. Use OEM whenever possible, we’re not talking about brake pads here, where aftermarket is typically where one wins, this kinda stuff is best to use OEM.
How serious is this?
A P0342 is rather serious. Enough to throw your engine in emergency mode at times. The main issue is that if you don’t take care of it, the constant failures in ignition timing will throw your MPGs to the floor, will fry your sparkplugs (potentially) and cause other myriad of problems in reading, which in turn, will add more DTCs to the point where the PCM panics and the car will just not start unless you plug in your reader and clean them up. Seen that before!
What repairs can fix the code?
The typical repairs that will take care of a p0342 are:
- Changing the battery
- Changing the wiring or connector for the sensor
- Changing the sensor itself
This code is sister to the P0341 and P0343, which are related to “high signal” and “range” (whilst this is low signal). If your car presents all three, it means the sensor’s reading is fully out of whack, which would point more to an electrical issue (broken sensors tend to “break” at one position, but don’t discard too quickly)
If you’ve plugged your code reader and see a p0342 code, accompanied of the symptoms mentioned above, just get on and start troubleshooting, not something you want to leave be.