p0344 - Bank 1 intermittent or single sensor

[blindsk02]

As the title states, I am recieving an error P0344 and cannot track this down, heres what ive done already:

1 - Tested both sensors ~ 1275ohms (800-1300 is what the shop manual states)

2 - Swapped the 2 cam sensors and the code stays the same - "Intermittent bank 1 or single sensor"

3 - disconnected the main harness connector for them, blew out and reconnected.

4 - Opened wiring covers and inspected the wiring loom/their specific wires looped across the cylinder heads - no breaks/looks good

5 - test alternator - good

Im lost here, ideas on how can i track this down?

 

[jal142]

Did you mean you swapped the knock sensors instead of the cam sensors? P0334 is a knock sensor voltage out of range.

 

[edmaz]

How is the vehicle running? Any performance or starting issues?

A scope is required in order to perform a complete test of the cam and crank signals, however there is some diagnostic testing that can be done with just a multimeter. You can test the reference circuit to see if it reads 5V, and also if the ground circuit is ok as well. You can also test via back-probing or by using a wire piercing adapter, to read the signal wire while the vehicle is running. There should be somewhere around 2.5V on the signal circuit, with some degree of fluctuation of the values, but no big bounce to a much higher or lower value.

Also, on some vehicles, it's possible for a VVT problem (actuator/phaser) to affect timing is such a way that a cam sensor code gets set (but no VVT code). I don't know if that's a possibility with your CX-9, but it might be something worth doing a bit of research on.

 

[blindsk02]

Did you mean you swapped the knock sensors instead of the cam sensors? P0334 is a knock sensor voltage out of range.

Sorry, P0344....damn fat fingers

 

[blindsk02]

How is the vehicle running? Any performance or starting issues?

A scope is required in order to perform a complete test of the cam and crank signals, however there is some diagnostic testing that can be done with just a multimeter. You can test the reference circuit to see if it reads 5V, and also if the ground circuit is ok as well. You can also test via back-probing or by using a wire piercing adapter, to read the signal wire while the vehicle is running. There should be somewhere around 2.5V on the signal circuit, with some degree of fluctuation of the values, but no big bounce to a much higher or lower value.

Also, on some vehicles, it's possible for a VVT problem (actuator/phaser) to affect timing is such a way that a cam sensor code gets set (but no VVT code). I don't know if that's a possibility with your CX-9, but it might be something worth doing a bit of research on.

Runs like nothing is wrong, no starting issues, no misfiring, hasnt died randomly or gone into limp mode........runs totally fine.


Ive come across the 5v line and wanted to test it and the ground but gave up for the day; 34 degree F here today, hands were getting numb and I could only do work with the wiring and such without gloves for 15 minute intervals

Can i test the line with the sensor detached/car running?

 

[edmaz]

... Can i test the line with the sensor detached/car running?

Reference and ground are checked at the disconnected connector with the engine off and key on. Signal can only be checked with the sensor connected and the vehicle running (or cranking).

Because the vehicle is running fine, I suspect that whatever is causing the P0344 is a borderline condition, and that the reference and ground will test ok, as well as the signal showing no big spikes.

Perhaps the condition is even borderline enough to be fairly transient. Have you tried clearing the code a few times, in order to find out how long it takes to get set again and light up the CEL?

 

[blindsk02]

Reference and ground are checked at the disconnected connector with the engine off and key on. Signal can only be checked with the sensor connected and the vehicle running (or cranking).

Because the vehicle is running fine, I suspect that whatever is causing the P0344 is a borderline condition, and that the reference and ground will test ok, as well as the signal showing no big spikes.

Perhaps the condition is even borderline enough to be fairly transient. Have you tried clearing the code a few times, in order to find out how long it takes to get set again and light up the CEL?

After clearing it tends to show pending on the reader within a minute or 2 of driving and then the light goes on after about 15 minutes of drive time.

 

[edmaz]

After clearing it tends to show pending on the reader within a minute or 2 of driving and then the light goes on after about 15 minutes of drive time.

Given that error checking is done multiple times per second by the ECM, it would appear this P0344 is indeed some borderline/transient condition. And that also means diagnosing might be very difficult as well, as with most sporadic issues. It's likely that even monitoring cam/crank signals with a scope might not be helpful in this case, because the waveforms would look fine the great majority of the time.

I'm assuming this is an older, non-Skyactiv model, but you can make that clear by posting the vehicle year. I know very little about the older CX-9 engines, but a quick check on Rockauto shows that it uses standard VVT solenoid/actuators. And checking/cleaning those solenoids is one of the few proactive things you can do, aside from throwing parts at it (which I'm guessing you don't want to do). So that's what I recommend, whenever you finally get a day warm enough to let that happen.

 

[blindsk02]

2011, non skyactive, shared the 3.7l Ford engine

 

[edmaz]

Ah yes, the big old 6, which might be more difficult for accessing the VVT solenoids, should you decide to try that.

Is there any emissions testing in your state? If not, you could of course just take a wait-and-see approach to the code. It actually may be easier to diagnose the problem, if there's a consistent performance issue occurring as well. Not that you want it to get worse, only that it's probably going to be very difficult to figure this out when it's taking so long for the ECM to confirm the problem condition and set the active code.

 

[jal142]

What does the oil look like? When is the last time you changed it?

 

[blindsk02]

What does the oil look like? When is the last time you changed it?

Last changed in the Spring and I havent looked yet. I was going to drop it off for a NY state inspection next week and an oil change but i think this code has to do with emissions so now the inspection has to wait until this is resolved.

Oil have something to do with a cam position sensor?

 

[jal142]

Last changed in the Spring and I havent looked yet. I was going to drop it off for a NY state inspection next week and an oil change but i think this code has to do with emissions so now the inspection has to wait until this is resolved.

Oil have something to do with a cam position sensor?

The VVT actuators are driven by engine oil. If the oil is contaminated or low the VVT actuators can start to act up.

The code you have can indicate an electrical issue with the cam position sensor or that the ECU is getting odd readings from the cam sensor. If there's nothing wrong with the sensors, wiring harness, or ECU, the VVT actuator might be behaving erratically.

 

[edmaz]

It's unfortunate to have an issue like this, in a state where emissions testing is required (no personal problem with emissions testing, just a statement of fact). So this obviously means you either need to get this code resolved quickly, take the vehicle off the road, or sell it (which would be a markdown with the CEL lit up).

If you're going to continue to DIY, I'd now strongly suggest removing and cleaning the VVT solenoids. That, along with testing wiring, are the only no-cost steps you can take, before having to get into the other stuff.

The other stuff comes next, if the circuits test good, and those solenoids turn out to be not very gunked up, and cleaning them does not eliminate the code. The cam and crank sensors are a catch-22, because the correct approach is to test the signals using a scope, however buying a scope (or having the testing done by a shop) would probably cost more $$ than buying the sensors and DIY installing them yourself. So although I never want to throw parts, in a case like this it's probably best from a cost perspective. Hopefully, something in that collection will eliminate the code. If not, it starts to get grim, with no inexpensive options left to try.

But if you don't want to continue the DIY route, there is one other possibility for you to consider, assuming that NY has one of those 'escape' options for their emissions testing. Typically an option like that will allow testing to be bypassed/waived, if the vehicle can't be successfully repaired after 3 tries by a shop, although the specific details might be slightly different in NY. If they have this provision, and you're willing to spend up to 1$-2K on this vehicle, then either the shop will fix the problem, or you would get the emissions waiver, after they try and fail the required number of times.

Good luck with it, however you decide to proceed!