P1140

[infinitiwoes]

I have a 2002 Infiniti QX4. Recently got a P1140 code. I switched the engine intake valve timing sensors to see if that was the problem and got the same code: P1140, so I know the sensors are okay...

At this point, what do I do?

Do I need to replace (or clean??) the Intake Valve Timing (IVT) control solenoid located in the engine?

Or, do I need to replace the Intake Valve Timing (IVT) control solenoid valve harness, which is more accessible?

Or, do I need to do something else entirely?

I appreciate whatever help can be provided!

[Towncivilian]

Welcome to NICO.

P1140 is the passenger side camshaft position sensor. Swap it with the driver's side - if the code changes to P1145, replace the sensor. If you'd like an exact OEM part number, provide your VIN.

This guide has some excellent information and pictures on the location of the sensors in question.

I had both P1140 and P1145 on my Pathfinder and I replaced both sensors with some Standard Motor Products sensors I ordered from Amazon (the part is in the guide I linked actually) and the codes have not returned for over two years now.

[infinitiwoes]

Towncivilian, thank you for the reply. I already swapped the sensors and the code did not change-I got p1140 again. So, now I'm wondering what I should do...

I have read in many threads that if the sensors are fine then it is a solenoid or an electrical problem...

[Towncivilian]

Oh, you did say you had swapped them in your first post. I should have read more carefully, my apologies.

Page EC-524 of the factory service manual has a diagnosis procedure. Please try to follow that as best you can. It looks like it will be fairly easy to rule out an electrical problem.

I checked for technical service bulletins for anything relevant to this code, but found nothing.

[SteveTheTech]

What is the oil level?
How many miles since the last oil change?

[infinitiwoes]

SteveTheTech-About 3000-3,500 miles when the light went on, but the oil level is fine and looks relatively clean for the mileage.

After checking the possible electrical problems as well as I could- I couldn't complete step 5. After finding and gaining access to the ECM (it took me a while), I couldn't access it or remove the harness connector the for the test. So, I figured if I replaced the solenoid and the light still didn't go off then we had found our problem (electrical!) and at the very least I could direct the mech to a specific area to save some $.

However, I replaced the solenoid and some 400 miles later the light went off! I was surprised it took so long for it to go off, but I am thankful nonetheless.

Thanks for the help. Hope this helps other owners with their own P1140 issue. Infinitiwoes no more!

[Towncivilian]

Glad to hear you've fixed the problem.