I bought a lemon!

[FX4OFFROAD]

Dear forum members,

I am new to posting on a forum like this so I hope I’m doing things right. I know there is etiquette about this kind of thing.

I purchased a QX4 that has been sitting for a long time. The truck surges when it is at operating temperature from 1200-1800rpm while in park or neutral. It also idles fast in gear enough to fight the brakes.

It shows a code for
P0031 Heater control circuit bank 1 low
P1140 intake valve timing control position sensor bank one
P0328 knock position sensor high voltage
P0505 Idle air control generic

I have replaced the iac and the cam shaft position sensor and seen no change. If I disconnect the iac and the computers throttle control cable I can drive it without it surging but I imagine this is a terrible idea.

Any help to get me going in the right direction would be greatly appreciated.

[Q451990]

to NICO! If you haven't found it yet, the factory service manual is available at www.infinitiservicemanual.com

There may be some high idle troubleshooting steps in there. On the Q45, not having the specified amount if slack in the throttle cables will cause high idle, but I'm not sure how the QX is set up. I'm not super familiar with the QX/Pathfinder, but hopefully some members that are more knowledgeable will chime in.

[barnaclebob]

How is it a lemon, were these codes not showing when you bought it? Did you make sure all of the ODB monitors were set?

If you search most of those codes individually you'll probalby find the solution on here somehwere. I seem to recall that the IACV issue might require replacement of the Engine Computer (Control?) Module (ECM) but could be wrong about that.

[FX4OFFROAD]

I was fooled by someone having removed the check engine light. I know that even the new Idle Air Control Valve moves to the closed position and remains there constantly even after the truck is shut off. Could that mean the ECM is bad?

[EdBwoy]

I am sorry you were taken advantage of by a dishonest person. Have you tried doing the idle/ throttle position reset?

It's in the FSM that q45 linked to, most likely in the EC section.

[PathyPop]

I was fooled by someone having removed the check engine light.

You mean they physically removed the light (the bulb)? And not just turned it off before you bought it? If so, that pretty serious.

[Blindaviator]

I was fooled by someone having removed the check engine light.

You mean they physically removed the light (the bulb)? And not just turned it off before you bought it? If so, that pretty serious.

When I picked up my 2001 Pathfinder last march I found the PO had removed the Check Engine light AND the battery light. The Alternator was out and it had the VVT solenoid code (he had taken the battery out and put it on a charger before bringing it down thus clearing all codes and making it appear everything was ok.)
I made it about 10 miles down the road before I started having issues.

[EdBwoy]

Unfortunately, it happens. Hence my advice in this thread:
2001-pathfinder-instrument-wire-help-t617032.html

[Q451990]

Good times... gotta hate a$$hats like that.