I own a 2003 Chevy Impala 3.4L V6 & Check Engine Light came on & it was not blinking. Checked it myself & got,
“Code P0341 Camshaft Position Sensor
A Circuit
Range/Performance
(Bank 1 Single Sensor)”
Told the mechanic & told him to scan it again. Called me later & car was all set $186.00 Drove it home & light goes off again so I bring it back. Found out he never re scanned the car & took my word for it. When he did he got the same code P0341, he kept the car and tells me later that the camshaft sensor is installed correctly so he just reset the CEL. Driving the car the next day and CEL goes off again and it is the same code. The mechanic is telling me now that he cant help me any longer, he did his job.
Anyone ever have a similar situation with the Check Engine Light / Camshaft Sensor ? I checked it myself 4 different times & the mechanic twice. Thanks !
That code can be caused from a stretched timing chain.
What this means is, the PCM detected the ratio of fuel control between the crankshaft position sensor pulses and the camshaft position sensor pulses did not equal 6:1. Condition was met 10 times during any ignition cycle.
Out of sync Cam/Crank signals can often be diagnosed with a twin trace oscilloscope. Some systems look for the camshaft TDC signal to be nearly in alignment with the crankshaft TDC signal and will not trigger ignition or injectors if even a few degrees seperate the signals. I seem to recall that a Subaru with right and left timing belts was very particular about the signals being synced.
And the GM 3.8L engine had a problem with the reluctor on the cam gear picking up iron dust and causing it to fail to trigger the sensor intermittantly.
Without all the high tech equipment needed on late model automobiles a shop cannot be profitable.
Car engines have two main shafts, the crankshaft and the camshaft. The crankshaft rotates exactly 2 times for every turn of the camshaft. So when everything is working correctly, they are sort of like pairs of ice skaters doing twirls, perfectly synchronized.
Both shafts rotate 360 degrees per revolution, right? And there’s a mark on each of them (actually on a reluctance wheel attached to the shaft) at 0 degrees, which, when it passes by the sensor each time, causes a signal from the sensor, and that signal is read by the engine computer. The engine computer expects those two signals be properly synchronized in time w/respect to each other.
You engine computer says it has looked at both those signals and thinks something is wrong with the synchronization. This is a possibly very bad situation since it could damage the engine. Just like if the ice skaters lost sync and crashed into each other. So the computer is rightly concerned. There’s two likely conclusions that can be inferred
There is in fact a mechanical synchronization problem; e.g. a stretched timing chain; or
The mechanical synchronization is actually ok; e.g it’s just a sensor problem.
Both conditions should be easy enough for a shop to check, the first with a timing light. The second by a visual inspection of both the sensors (cam and crank) and their respective reluctance wheels and gap, and if necessary, inspecting the signals from the sensors.
Do you have sparkplug wires or are the coils mounted right on top of the sparkplugs? If you have sparkplug wires, you have the lost spark system. The camshaft position sensor is located under one half of one of the coils and is just a capacitive plate that lets the computer know when that side of the coil was firing on the compression stroke vs the exhaust stroke.
That system is very reliable, but a bad spark plug or spark plug wire is most likely the source of the code. It does not mean that it was bad to the point of a misfire, just that the properties of the spark were not what was expected. The properties of the spark are affected by the ionization of the gasses around the spark plug tip and the compression of these gasses, so the spark is different with fuel/air and compression vs exhaust gasses with no compression.
If it is coil on plug, then the camshaft position sensor is different.
If you have sparkplug wires, you have the lost spark system. The camshaft position sensor is located under one half of one of the coils and is just a capacitive plate that lets the computer know when that side of the coil was firing on the compression stroke vs the exhaust stroke.
Ummm…no…the car has spark plug wires and 3 coils and what’s under the coils is the ignition module. Cam sensor has nothing to do with that.
Your camshaft sensor does exactly what its name implies, gives information to the engine computer about where the camshaft is in its rotation. The fault could be caused by a failed sensor, a wiring problem, possibly an ignition module, or a mechanical fault inside the engine. Which of these is the issue is fairly easy to determine for a mechanic with basic diagnostic equipment.
It sounds like your mechanic is either unwilling or unable to do any further testing. I would ask around for a referral to a competent local independent garage. A $100 diagnostic should easily get you to the bottom of the problem.
It’s a shame that the public is so put off by diagnostic charges @asemaster. Somehow most people are more acceptable to paying for uneeded parts and repairs to an unqualified mechanic than paying for a proper repair done after a professional diagnosis. Go figure.
In defense of the people who balk at a simple $100 or so diagnostic charge, they may have been bitten before by the shop down the street who offers that same service but is wholly unqualified to do it. They often have a generic code reader or smartphone app that they think is all they need. They simply begin at the top of the list of possible causes for a fault code and call that a diagnosis. It’s a shame, because in the grand scheme of things proper scan tools, labscopes, service info, and associated items are quite inexpensive when used properly.
