# 2005 Maxima limp mode, no obd connect, electrical problems



## sinistersf (Jun 14, 2016)

I bought a 2005 Maxima yesterday and it has some serious problems. The previous owner didn't want to mess with it and didn't give me any information to go on.

It had a dead battery so I jump started it. It fired up but had a high idle, slammed into reverse and when driving it wouldn't accelerate. I guess this is a limp mode.

All of the lights in the dash were lit up (TCS, ABS, Trac off, etc) except the service engine soon light, it's not on at all.

The tach and gas gauge aren't working and the climate control unit isn't functioning. I shut it off and restarted it a couple times yesterday, it stayed in limp mode. I tried to connect my code reader to it but it's not communicating with the car.

I charged the battery last night then popped it in and tried to start it, now it cranks and cranks but won't start.

I don't really know what could be causing all these problems and I don't know where to start, any help would be greatly appreciated.


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## smj999smj (Jan 1, 2006)

Engine limp mode limits the engine RPM to 2500, at which point is will surge violently. Auto trans limp mode keeps the transmission in 3rd gear. Having the battery disconnected for a long time can erase the learned idle air volume memory, which will cause high idle and set a P0507 code in most cases. The fact that you can't communicate with the ECM is a concern. ABS/TCS/VSC warning lamps can be triggered by a faulty ABS wheel speed sensor or circuit problem...but, they can also be turned "on" when there is a charging system issue or an engine management issue, which will cause the ECM to disable the TCS/VDC systems.
The first thing I would do is make sure the charging system is operating properly. Charging voltage on Nissans is typically around 14.7 volts, but 13.2-15.0 volts is acceptable. Make sure charging voltage is within spec @ idle and @ 3500 RPM, with loads "ON" and with loads "OFF." Make sure the battery connections are clean and tight. 
If that's good, turn the key to the "ON" position, engine "off." This should put the instrument cluster into bulb check mode. Make sure the CEL illuminates. If it doesn't, you'll need to do some circuit tests to diagnose while the light won't come on. It could be an open or shorted wire or it could be a bad ECM. There is also a diagnostic procedure to determine why there is no communication with the ECM. You are going to need a factory service manual for your vehicle. This will give the procedures to check these systems as well as circuit diagrams. There are a number of sources of free, downloadable manuals on the web. Nico Club's site has full manuals for download and NissanHelp.com has individual chapters for download in their "knowledge base" section. Hopefully, you got a really good deal on the vehicle because you may need to put some money into it in order to get it straightened out.


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## sinistersf (Jun 14, 2016)

Thanks for the reply, I got the service manual, but it's huge, going to take a bit to dig through it. 

The CEL isn't illuminating when I turn the key to the on position. 

Where should I look in the service manual for a diagnosis procedure? 

I'm also looking for the troubleshooting guide for cranks, no start. 

Someone has been messing with the fuse box and all of the junk under the dash. I'll probably start poking around with a volt meter but I'm not really sure what I'm looking for. 

Is there a way to test the ECU to see if it's toast?


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## sinistersf (Jun 14, 2016)

Update*

So I left the battery disconnected last night, this morning I went out to try it and it fired up. It's still in limp mode with no service engine soon light working. I tried doing the 3 reset or relearn things (off pedal, throttle body position, and idle relearn) but they aren't working. If the SES light isn't working at all does that mean my computer is screwed? I don't understand how it can start and run at all if the computer is toast.


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## sinistersf (Jun 14, 2016)

I got the Maxima back from my shop today, they scanned it and the TCM failed. So I scooped up a matching one off of ebay today and while I was at it got a new climate control amp because coins fell in to the old one and burnt it up. Have you guys seen this before? Hilarious, what a crap design.

Anyways, I've read that the TCM is plug and go, I figured I'd have to take it to the dealer to relearn something. Anyone have experience with this?


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