P1140- Mass Air Flow Replaced-Still Have SES Light

[mateen110]

Ok Here is the story.

I have a 2001 Nissan Pathfinder and a 2002 Infiniti QX4, both have SES Lights and both at around 100k.

I took the Nissan for an oil change, and the mechanic there went ahead and did the diagnostic for free, and said error code p1140 (intake valve timing control position sensor). He did the Infiniti too, and said it had the same code (intake valve timing control position sensor). He then proceeded to say it was the mass air flow sensor on both cars. I then replaced the mass air flow sensor on both cars, went to autozone to reset the code, and within 5 minutes, the code came back on both cars.

After further research, it seems as if I need the camshaft sensor. p1140 is passenger, while p1145 is driver side. Therefore I should just replace both on both cars? Is it the camshaft sensor or is it something else? I don't want to throw more money at the cars and not get a fix. I guess I learned my lesson of researching yourself before trusting a shady mechanic.

Should I follow this guide here?
http://www.jensbits.com/2008/08/30/path ... and-p1140/

Thanks!

[Towncivilian]

Both P1140 and P1145 codes refer to the camshaft position sensors (though which code refers to which side eludes me right now, sorry). Since you only have P1140, you can try swapping in the other sensor to see if the code goes away; if it doesn't, you have a bad solenoid and not just a bad sensor.

I bought two generic camshaft position sensors from Amazon for about $60 each and replaced them with a friend's help in a couple hours (the engine has to be cool before attempting to replace the sensors). We had more difficulty removing the old sensors than putting the new ones in. My Pathy had both P1140 and P1145 (for several years, probably) before I replaced the sensors a few months ago. No SES light anymore.

I followed that exact guide.

[Chuck Tribolet]

P1140 is US passenger's side camshaft position sensor.

And a Nissan Dealer replaced the MAF? That's just plain incompetant or fraudulent and I'd be talking to the service manager and saying I wanted a complete refund.

The sensors aren't hard to get out. Unplug, one bolt, and wiggle a bit. They have an O-ring, not a flat gasket, and if the O-ring isn't damaged (I haven't damaged one yet), you can reuse it. Just smear it with a drop of oil off the dipstick before you reassemble. This will allow it to slide in to place with out deforming.


Chuck

[asnorton44]

Yeah I had the same code and replaced my sensor ($75), I had to replace the MAF also but I don't believe it was related to this problem.