01 Maxima in BIG trouble; Coil, MAF, IAC

[wazzupwaleed]

So i have a nissan maxima 2001 20th Anniversary edition with about 280k and CEL always on. Runs well til a few days ago wen, as a perfectionate I wanted to make sure my car is all well. n using a diagnostic tool i got the following codes.

P0300 x2: Random Misfire

P0100: MAF sensor

P1320 x2: Misfire detected

P0505: IAC

now I need an experts advice, i want to know how serious is this problem? Can it be fixed using used parts? It has 280k and i am a student and need a reliable car n seriously dont need a car problem expense right now, so should i sell this? I have no problems with working on a car if basic tools are needed and good instructions are provided. So guyz, save this maxima (or me)!

[loystock]

Yes, it looks like your in big trouble.

It's never a good idea to ignore the CEL as it could lead to more serious problems. And this may apply in your case. It's possible that your IACV was failing (P0505) which eventually 'fried' your ECU. The IACV has a stepper motor whose driver (power transistors) is inside the ECU. A short circuit in the IACV will cause the driver to overheat and affect other ECU components nearby.

If the ECU is confirmed bad, you can buy refurbished or new ECU. Once installed, you car will not start due to NATS (Nissan Anti Theft System) since the your Ignition Key ID no longer matches the one inside the new ECU. You have to bring your car to the dealership, with all keys, for reprogramming.

The P0300 and P1320 may be related to ignition issues (coils, plugs, condenser, connector, harness, etc.) or may be due to ECU failure. Make sure you address the MAF, IACV and probable ECU problems before looking into this ignition/misfire problems.

A problem with the MAF may or may not trigger a fault code but in this case, you have P0100 which is specific to MAF sensor, connector or related harness. You can try cleaning the connector and the MAF sensor with CRC MAF Sensor Cleaner (@ $8 from Autozone). If it did not work, you have a choice of buying refurbished or new MAF sensor. A faulty MAF sensor may cause your engine to run rich and over extended period will prematurely kill the O2 sensors and catalytic converters (very expensive). There are 4 O2 sensors and 3 'cats' in your car.

Here is a link to the FSM to help you in fixing your car.

http://www.nicoclub.com/FSM/maxima/2001/EC.pdf

[wazzupwaleed]

Thank you very much for your help. Im just sad that a car that looks so perfect from outside, is messed up inside. It never gave a problem before.except every once a month it would stutter and then after a few seconds it would smooth out. I was spending my bucks on suspension lyk a fool. Anyways. while i was waiting for the reply, i went to check out some used car parts ....i found 3 nissan maximas...one was really in good condition...with 75,000 kms. I was thinking i could use that car's IAC, ECU, MAF but for the coils maybe buy new ones.

4 months ago, i did clean the MAF, thinking it would increase fuel economy. I used an electrical contact cleaner. Well the results were there, but just for the next 2 months.

I will keep updating you, right now the car IDLE is very high, and it varies up n down wen on park or neutral. I guess i ll just stop driving it till i get it fixed.
Just one confusion, on ebay, there are ECU for many different components, like Chassis, transmission, etc. Isnt ECU one unit for the whole car?

So what is your estimate on all these repairs, excluding labour? incase i buy everything new.

[TOMMY VERCETTI]

I wish you the best Dude.

[loystock]

Control Unit is generic but ECU/ECM (Engine Control Unit/Module) is specific to the engine, TCM (Transmission Control Module) for transmission and BCM (Body Control Module) for the body.

You can get discounted price (25% off MSRP) from IoS (infiniri of Scottsdale) - infinitipartsUSA.com a.k.a. "everythingnissan.com." Even at discounted price, price for new parts, including coils, will be > $1500.