I just replaced Valve cover gasket (front) and valve cover (rear), plugs and PCV valve on 2003 Infiniti I35, 3.5. Of course this was quite a task for me, and a job I have not done before. After everything was back in place, the car runs fantastic and there are no more oil leaks. After two days of driving the service engine light came on. Checking the code, I got a P1800. The next day the TCS off and SLP lights came on and the engine was a little difficult to start a couple of times. After turning the ignition off and then back on, the engine started just fine and the dash lights went off. Then two days later they came back on. The code reader showed 6 codes. Two of them were P1800 and four of them were P0340. I reset the codes and service engine light and all other lights went off and the car ran just fine. Then tonight after driving about 50 miles it did it again. Looking this up, I find information about the VIAS solenoid and the Camshaft Position Sensor.
None of this was happening before I replaced plugs and valve cover. Of course I had to disconnect several connectors and remove the intake plenum to do all of this. Where do I start diagnosing the problem? Does anyone think there is a relation to my work on the valve covers and plugs and what is happening now? I have downloaded the 2002 3.5 manual PDF.

 

- Faulty VIAS control solenoid valve
- VIAS control solenoid valve circuit harness is open or shorted
- VIAS control solenoid valve circuit poor electrical connection
Maybe the wires loose or unplugged after you removed everything?

 

^^^ that's for P1800.

P0340 is the bank 1 camshaft position sensor (PHASE).

Here is a link to the service manual about P0340. Go to page 317 and start reading about it.

http://boredmder.com/FSMs/Infiniti/I35/2003/EC.pdf

On page 322, there are some things for you to check.

Also in this section, P1800 is discussed starting on page 632.

If you want the entire service manual:

http://boredmder.com/FSMs/Infiniti/I35/2003/

 

Thank God for a long weekend. I think I'm gonna be busy with these codes. I appreciate the input. I'll let you know how it comes out.

 

This was the same thing that happen to my 2002 maxima.

Just change the solenoid valve and replace the camshaft sensor which would be a green connector.

For my maxima it was bank 2 and it only took a few minutes to change.

 

Ok, so I am still getting the P1800 code. I tested the harness and am getting 12V at the harness. I pulled the VIAS solenoid and bench tested it. I was told that it is supposed to "click" when voltage is applied. It did not. I'm assuming now that I have a bad solenoid and will order one.
Over the last two days the engine has gone dead while driving, (at low speed). This has happened twice. I turned the ignition off and it immediately cranked right back. No MIL or engine lights afterwards. The car seems to run great, however. Is this related to the VIAS solenoid?

 

cam sensor is bad

just replace both

 

thanks. Will do.

 

Let us know...the 1800 code error is a very common issue.

 

Still have the P1800 issue. Car was running great after replacing valve cover gasket, and valve cover and plugs. Then I began to have trouble with shifting and traced it to the camshaft position sensor, which I replaced. Everything was great. Car running great. 28 mpg on hiway. I did notice that the idle was lower than usual. (700- 900 rpm). Then I was sitting with the car idling and the check engine light came on. Checked codes: P1070, P1072, P1448,
Changed my very dirty air filter and reset codes. The check engine light has not come back on since, but car is idling way to low. I have to put it into neutral when I am stopped in traffic. Took it on a road trip, (300 miles) and it runs great on the road.
I don't want to just start replacing stuff by trial and error. It wasn't doing this before I changed the camshaft position sensor. Any link to that?

 

Take the VIAS controller off your car and Bench Test it. You can hear it click open and close. Check You Tube for this test.