# Help: check engine light on.



## frankfmwu (Apr 5, 2005)

Hi

My Altima (1995) check engine light went ON from last year. I didn't try to fix it because it still runs well. But this month I must do it because of smog check can't pass ... 

The light went ON after the O2 sensor (rear one) drop from the pipe (The car from East so the pipe is damaged badly) . I inserted the O2 sensor back to the pipe, and nothing goes wrong expect the Check Engine Light is On. 

These days I went to mechnics and he checked it and found two codes: 

P0352: Knock sensor 
P1400: EGR & Canister Control Solenoid Valve 

He fixed the first problem by replace knock sensor and clear the codes. But after I drove about 10 minutes (local), the light went on again. He checked the valve and solenoid and said they are right. But it happed again after I driove 20 miles (highway). 

Really appreciate any information .... 

-Frank


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## Agoudine (Feb 19, 2005)

You can check codes yourself. Buy Haynes Repair Manual in an auto part store or online for about $15. It will show you how to read codes, identify them and reset without special equipment.
I've had the same problem with rear 02 sensor. You will ned to replace catalytic converter in order to install new o2 sensor in it. If replacing the converter alone is impossible, you will need to replace it together with all pipes attached to it (it is probably very old and needs replacement anyway).
It is cheap and easy to buy all exhaust parts online - about $ 150 for good catalytic converter, $ 115 for 02 sensor.


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## peeryml (Jul 10, 2005)

*Same Problem DTC105 (P1400)*

Hi, I recently had the EXACT same problem.

I read the codes from the ECM and tried to find something wrong. Based on the two codes and as a guess, it looked like something in the EGR caused a lean burn which probably caused the knock sensor indication so I focused on the EGR solenoid (looks like the guy that replaced your knock sensor was shot gunning). Everything checked out perfect. So I cleaned the solenoid contacts and the engine ground wires and cleared the codes.

Two trips later MIL light came back on and I checked for codes again. This time just a DTC105 (P1400), so it looks like an intermittent problem in the EGR solenoid or its circuit. The circuit is fairly simple so it's either the solenoid, one of three connectors, or the ECM (I hope not). The connectors are very difficult to get to. I'm debating with myself whether or not to replace the EGR solenoid.

Did you ever get this problem tracked down and fixed??


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## KA24Tech (Feb 2, 2004)

Check all the hoses from the solenoid for brittleness and cracks. I recommend changing them out with silicone hoses.

Troy


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## peeryml (Jul 10, 2005)

Hi, replaced the EGR control solenoid as a first try and the DTC has not come back after a couple of trips. Looks like that might have been the problem. 
I tried it because the factory service manual says that the DTC105 (P1400 generic) code ONLY comes in for an electrical problem with the solenoid circuit. There's other codes for malfunctioning EGR mechanical components. Good luck.


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