Hi guys I’m looking for some help in solving a p0340 error. It is saying ‘camshaft position sensor A, bank 1 circuit malfunction. Engine is 2.3 v5 170 (AQN) The car barely starts runs terribly. I tried replacing the camshaft sensor but that didn’t make a difference. I have since replaced timing chains/guides and the fault is the same. I have tested the camshaft sensor plug and there is the correct voltage. Just not sure what to try next! Resistance from the sensor plug to the ECU?
Hi! What brand and part number sensor did you use, also could you send a picture of the sensors installed and plugged? Not sure if its possible on a V5 but the wires might be switched. And its the timing 110% right?
Hi thanks for the reply. I have tried two second hand sensors from a breaker and they are Bosch ones. I will try and get some photos this afternoon. Im confident about the timing being correct because after the engine rebuild etc with no luck I basically started all over again from scratch. The engine turned a number of revs by hand and the cam locking tool slot into place perfectly. All marks lined up
Hi, no worries. If its timed right which is sounds like it is, it's almost certainly going to be sensors. What voltages on what pins did you measure? You can also try swapping the sensors round, so physically move the sensors from exhaust to intake and see if the fault follows. Its possible the "new" one is dead but hopefully that will rule it out. And yeah its a bit painful but Bosch or nothing for sensors on these, saves so many headaches
I tried swapping the cam sensors but the fault didn't follow. Yesterday I also changed the crank sensor but that didn't help either. The voltage at the cam sensor plug were: Pins 1 and 3 = 4.9v Pins 2 and 3 = 10.7v
That seems about right. You can cross check with the other sensor too. The official procedure is: Pin 1 - Engine ground: 5 volts Pin 2 - Engine ground: 12 Volts ish Pin 3 - Battery positive: 10 Volts ish Just to check you cleared the codes after moving the sensor? If that checks out it's most likely going to be a VCDS job
Thanks y Thanks yeah I just checked again and the voltages are as you say. Is it worth checking continuity from the signal wire to the ecu end of the wiring loom?
Not really, if you get the voltages then the wiring is okay. The signal wire is the one that the ECU puts 10/12 volts on, so pin 2. And as the voltage is there, that means all is well. Where abouts are you located, someone on here might have VCDS near you
ah okay! yeah my understanding was a bit off. Im in South Wales and yeah I think im in need of a proper VCDS at this point hah.
Yeah they're a bit odd to get your head around. They have the power supply which is Ground and 5 volts, then their "signal" output gets the 10 volts from the ECU. When the trigger wheel goes past the sensor that 10 volts gets connected to ground (not quite but the effect is similar) and the ECU can detect that. That's why that type of hall sensor are a bit hard to test off the car. You should test them by back probing the connector while its connected to the ECU, because they don't generate a voltage output on their own like you'd expect. Yeah it's very helpful, will tell you actually what's going on. For example might say the sensors are out of phase which would imply wrong timing, or more likely in your case, one of the VVT actuators or solenoids is stuck. You can also view sensor readings while the engine is running to check that things are logical, and for example you even get a reading from the cam sensors. It might even be an error with a totally different sensor, which VCDS will specify, rather than the generic code shown on your reader.
Just one more thing, im trying to be thorough with the wiring not being at fault. I know now that the voltage is correct at the sensor but what about testing the resistance from the ECU to sensor? Im just scratching my head at what's still wrong and causing the fault code
You can check it, but I doubt you'll gain much and its a faff to get to the ECU. The current is very very low and the chances of you getting a high resistance connection in that wire are very slim, its straight to the ECU with no splices. As I say it could be stuck actuators, solenoids or something totally different.
Thanks again. I’m going to strip it back and take the upper timing chain off then inspect the vvt solenoids. I just thought that would have shown up a code of its own?
It wasn’t really like sludge but very dark oil. The car has missed loads of oil changes and hasn’t been very well looked after
When I get that far… is it just a case of taking the two solenoids out and giving them a clean? Also you mentioned actuators what are those? Anything else to inspect while I’m there? This has to be the last time I take the engine apart haha
It will on VCDS but not on a generic normally. VCDS can all so tell you timing is wrong whereas a generic generally won't. Ahh that could be it then. I'll try and find a guide. The actuators are what sit on the cams and actually move them, they can get stuck or sludged up. You can remove them from the cams and soak them in acetone or similar to free them off. The solenoids I think you can remove from outside the engine so that might be worth doing first. They are what control the oil flow to the actuators.
I’ve spent a couple of hours on it just now and got as far as removing the upper timing cover. Oddly… the timing seemed slightly off at TDC. The exhaust cam was perfect but the intake camshaft was slightly rotated forward too far. Just the other day when I timed it and rotated the crank pulley twice the cam tool slotted straight in (all with the timing cover and tensioner bolt in) so thought it was right.
