P0340 - Camshaft Position Sensor Circuit Malfunction
Unfortunately that code isn't very descriptive, but it suggests it's not an electrical problem. About all you can do is measure the voltages on that sensor but you have to do that with it plugged in by back-probing through the rubber seals. Typically you can expect to find 5.0 volts on the feed wire, and 0.2 volts on the ground wire. Beyond that you need a scanner to view live data to see if the signal is present.
Very often cam and crank sensor codes don't set just from cranking the engine. They set when the engine is coasting to a stop during stalling. You have to work with the code you read before any service was done or the battery was disconnected to erase the code. That's why it's important to read and record them before anything is done that will erase that memory.
The only way to test the computer is with very expensive specialized equipment that only the rebuilders have. For the rest of us, all we can do is to be sure we have all the 12 volt supplies, all the grounds, and all the proper inputs. If we have those and the computer is good, we'll get the proper outputs, ... Provided nothing is shorted on those circuits. There's often four 12 volt feeds and four ground wires. If you're missing the 5.0 volts to the cam sensor, that circuit feeds a number of other sensors, and any one of them could be shorted. To find that you'd have to unplug them, then turn the ignition switch off and back on to reset the power supply. Once you get the voltage back, monitor it as you plug each sensor back in. You'll set a lot of fault codes but it will identify which one is killing the 5.0 volts.
Thursday, July 31st, 2014 AT 7:43 PM