# 2001 Maxima P505 error



## Sunny Kins (Mar 30, 2013)

My car stalled on the highway, took it to my mechanic and he found the check engine light on and attributed to IAC and replaced it. It was a P500 code. Got it running for a week and had the check engine light back on! now the problem was P505 and seems the ECM was fried .... asked to get this done by dealer as a new ECM is needed and needs reprogramming ...total cost $1300.

Was reading other forums and seems if i replace ECM need to replace IAC...basically both need to be replaced at same time

my questions
1. Should i again go for replacing IAC...it will be another $300
2. can i buy ECM from non-dealer and ask dealer to reprogram. DOes anyone know if the dealer will reprogram a non-Nissan ECM 

please help , already put lot of money on fixing ...want to make sure i have some options before i approach the dealer


----------



## rogoman (Dec 16, 2004)

The P0500 code points to a problem with the vehicle speed sensor not the IACV. Did the speedometer stop working?

The P0505 points to a problem with the IACV. Since it was replaced, the harness connectors may not be secure. What makes you think the ECM is fried? How is the car actually running.

Looks like somebody may be guiding you down the money trail. Get some other opinions!:waving:


----------



## smj999smj (Jan 1, 2006)

There was a problem in some of the early A33 Maximas where the IACV-AAC valve would start leaking coolant and would short out the circuit, damaging the ECM. So, you don't need to replace the IACV-AAC valve just because you are replacing the ECM, but, one would want to make sure when replacing a damaged ECM that it wasn't caused by a leaking IACV-AAC valve. Since you already replaced the IACV-AAC valve, you shouldn't need to replace it again. If you are buying an ECM, it should already be programmed. What you will need to do is have the keys initialized so the vehicle will start due to the immobilizer system. Once the vehicle starts, the idle air volume will need to be learned as well as the closed throttle position. The ECM program should also be checked to make sure it is the latest version. If you replace the ECM yourself, you will need to tow the vehicle to the dealer (or a locksmith that has key initialization capabilities) to initialize the keys. It's hard to know if the closed throttle position is "learned" without access to a scantool that can view the datastream. As far as the idle air volume relearn, there is a manual relearn procedure in the FSM, but it's a lot easier if you have a scantool with that capability. There shouldn't be any issue with a dealer doing any of those tasks if you install an aftermarket ECM, but you will not have the Nissan warranty on the part and of course they will assume no responsibility or liability of any problems that could be caused by the aftermarket part.


----------



## Sunny Kins (Mar 30, 2013)

hi no issue with speedometer it was working fine so not sure if the p500 was actually an error. i had all the p505 error symptoms mentioned in the forums...No start, hard start
Engine stall, Rough idle, high idle, erratic idle. so looks like i am pointed in the right direction...will have to check on harness..

Thanks


----------



## Sunny Kins (Mar 30, 2013)

smj999smj ...thanks

I checked with dealer, as you said...they will do the reprogramming but will not assume liability for any issues resulting from that part. 

I was checking some alternatives and was directed to Circuit Board Medics who claim to rebuild the ECM for $200 once i ship the part to them, does not look like any reprogramming is needed and there is manual relearn procedure involved. Worst case i can still go to dealer with the same ECM and ask to reprogram. Please advise if this looks like a viable solution or is this another scam


----------



## smj999smj (Jan 1, 2006)

The manual relearn is probably for the idle air volume, not for the key initialization. I guess it's possible they could repair your ECM and retain the key initialization memory? You should check with them. The ECM will need to be installed in the vehicle for them to reprogram it. There are a number of companies that repair ECMs. I haven't used Circuit Board Medics, so I can't really comment on them, good or bad.


----------



## Sunny Kins (Mar 30, 2013)

I checked with circuit board medics, they claim no key initialization required. Manual relearn is for the idle air volume. i have sent the ECM to them now, hopefully this gets sorted out soon


----------



## Sunny Kins (Mar 30, 2013)

ok, so i got the ecm repaired by circuit board medics, did the relearn and again got the P0505 (confirmed by a free OBD scan deal) . The idle rpm was 1000 whereas should have been 650-700 rpm. I called circuit board , they said its possible the iac was non-nissan or issue with harness or throttle. I know my IAC was a nissan part, harness also ok and my mechanic did adjust the throttle to be high. Is it possible to have P0505 if throttle is high or did i just waste another $200 bucks?


----------



## smj999smj (Jan 1, 2006)

Adjust the idle per the FSM and relearn the IAV.


----------



## Sunny Kins (Mar 30, 2013)

All fixed! I went to the mechanic and asked to correct the throttle...he said my previous mechanic had adjusted the throttle and that should never have been done ...also said there was no specification existing on where it should be so had to take a best guess and correct it. Well all said and done, looks like everything is working now !

Thanks all for your help and suggestions...


----------

