greenschemes

OK, so I've had a huge problem with 2000 Maxima.. Thought I'd try one last time to fix this car before giving up completely.. Shame because she's pretty. So my brother gave me his Maxima and said if you can fix it, it's yours. Originally it wouldn't idle but if you started it and kept the peddle pressed she would run fine. One of the codes was a p0505. I've replaced IAC, Throttle position sensor, fuel pump and filter, checked the ECU( looks fine), new injectors, new spark plugs, cleaned the MAF, replaced the MAF, tracked down a leak in the intake manifold( stripped thread, drilled all out and heli coiled) new gaskets and fixed another hose that was leaking. Finally got her to idle but really high, about 1100 rpm but she kept surging between 1500 and 2000 rpm. A mechanic I talked to said it needs a ECU reprogram but have a smoke test done first to make sure all leaks were fixed. I drove it to Autozone and had codes pulled 3 codes fixed but the p0505 was still there. So I went to Pep boys to have a smoke test done. After wandering the store for about 25 mins, I returned to find the car still in the parking space and 2 mechanics under the hood and 1 behind the wheel. The 2 under the hood immediately left without saying a word, kinda weird. The guy behind the wheel claims it wouldn't start and that they thought the battery needed a jump.( the engine was turning over fine just not starting). So I start looking around and found a sensor unplugged and a wire harness for one of my injectors broken. Not 100% sure but I think they were about to set me up for a huge bill... (exactly why I twist my own wrenches).. Anyway< had to have it towed and haven't been able to start it since.. now I have 2 codes p0505 and p0100.. the thing that was disconnected is attached to the intake manifold not sure what it is.. Any help would be greatly appreciated.

DennisMik

iTrader: (2)

The broken fuel injector connector will not keep the engine from starting.

The P0100 could. This is the Mass Air Flow Sensor or MAF for short. Was this the connector that was you found disconnected?

Disconnect the MAF and see if the engine will start. Many times it will but you won't be able to drive the car.

The MAF connector is the same kind as the fuel injector. You have to push the green tab down into the connector until it clicks and releases. The "expert" mechanics at PEP Boys obviously didn't know this. They may have wanted to remove the MAF connector and couldn't and were experimenting on the fuel injector because it is easier to access.

But the P0505 is a problem. The code is for the IACV, which you said you have replaced. This problem is that when the IACV goes bad, it shorts out the control circuit in the ECU. Replacing the IACV doesn't fix the damage inside the ECU and the code (and idling problem) doesn't go away.

Obvously you can replace the ECU, but a new one is extremely expensive. There are repair services, google ECU repair, or you could fix it yourself if you know how to solder. A junkyard replacement, if you can find a donor car that is equipped just like yours, is another possibility.

Here is a link to a real long thread on this. There are also many more threads on this subject.

http://forums.maxima.org/5th-generat...d-seconds.html

post # 5 explains what the chip does.
post # 27 has an ECU picture with a fried chip.
post # 29 has photos of the repair process.
post # 38 has photos of fuses being added to the ECU.
post # 70 states ecu repaired for $70 by autoecu.com
post # 78 states 2 places were the chip were bought.
post # 86 is another ECU repair place that charges $160.
post # 93 guy has a 2000 Infinity I30T & his ECU is slightly different.
post # 98 another guy with a 2000 Maxima has same ECU as infinity.

SrgScott

iTrader: (2)

Sounds like you only have one problem

P0505, Idle re-learn, and ECM reset (done on-vehicle with it running). Complete.

Im quite sure the P0100 will go away after the idle re-learn and resetting the ECM as per the nissan FSM.


Oh, and there are literally five or six threads with damn near all the info you need on these codes (including what i just stated above). Search button, sort results by relevancy

greenschemes

Already tried disconnecting the MAF didn't help. when I checked the ECU there wasn't anything fried. The idle relearn needs to be performed on a running vehicle, which now mine is not. Bit of a catch 22. I attached a couple photos of the thing that they unplugged not sure what it is.

DennisMik

iTrader: (2)

I'm not sure what PEP Boys unplugged. The first 3 photos you posted are of the Power Valve Actuator, so is this what was unplugged?

This is part of the VIAS (Variable Induction Aircontrol System). VIAS is/was an attempt to fudge with the intake port length which would have an effect on the engine's power output.

I don't know much about this, but even if this didn't work, I'm pretty sure the engine would still start. Could be wrong though.

A possible thing that may have happened is that they tripped the NATS immobilizer. Is the red security led that is in with the clock on?