#1
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02 Pathfinder Possible ECM
Hi Folks,
A little background here... Saturday - Kids called from two hours away and told me that the 02 Pathfinder with a 3.5 motor had died and would not start back. After some basic, remote, troubleshooting, I called and had it towed to a dealer. On Monday morning, the dealer called and told me that the key had to be reprogrammed, however, that did not resolve the issue and they would keep trying to find the issue. A few hours later, they called and told me the IAC Valve was shorted and needed to be replaced. Since I was two hours away, I had to do something to get the car running again, so I authorized the repair. The part would be in on Tuesday morning. Tuesday afternoon, I got a call and was told the car was now running, however, they were unable to get the car to take the idle relearn from their computer and they "thought" it might be because the IAC had shorted the ECM on the driver control. They quoted another $1200 for the ECM and another 1.5 hours labor. I asked them if they had tested the TPS and it was checking out good. I also asked if it was throwing the infamous P0505 code and they said there were no codes, however, they could still communicate with the ECM. To shorten this up now... I drove up and picked up the car and drove it home with the idle going up and down, especially at stop signs/red lights. I called my local dealer and they said they would reprogram and install a used one if I brought it to them for a one hour charge. Before I hit the salvage yard and get an ECM, would anyone have suggestions of anything else to check or try before shelling out more money? As well, if it is the ECM, is there a way to manually reset the used ECM to work with my current keys and avoid having to take to the dealer to reprogram? Who knows, maybe the used one will come with keys and a security module to replace as well and then no dealer needed. Thanks for any advice or input here. |
#2
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The ecu will have to be reprogrammed again.
make sure you get the same number that is on the ECU |
#3
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Thanks. I'll pull mine in the morning and head to the yard to see if they have one that matches. From looking at your circle, I will be looking at the area the "CC" is circled for a match, correct?
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#4
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My understanding is the shop installed a new IAC and car is now running with erratic idle. It is expected. You are supposed to do the Idle Air Volume Learning Procedures. I am not buying the ECM is shorted or fried due to the faulty IAC. It's true this can happen but with a fried ECM, the car WILL NOT START even with a new IACV. Try do the IAVL yourself. Click on DIY then your Vehicle Model then Engine Control.
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#5
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The ECM will have to be replaced or repaired when the Idle air control valve goes bad it burns the ECM, we have replaced/repaired many of them do to this issue.
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#6
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They tried the idle relearn using the consult, with no luck. I also tried it once I got it home and had no luck either. Typically, from what I've been reading, when the ECU is shorted, it will either continue to read PO505 or not be able to communicate. The tech told me he felt the ECU was shorted on the driver side controls since the idle wouldn't reset.
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#7
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I'm also going to pull the ECU and see if I can see any damage to the boards. If I do, I guess I will run up and hit the salvage yard so I can run by the dealer and have them reprogram the keys and idle on the "new" (used) ECU.
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#8
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Well, I pulled the ECM this afternoon and the board is definitely fried. Right at IC17, the electronics have exploded. I spoke to Circuit Board Medics and may take it or send it down to them. The are about and hour and a half away and get really good reviews. I have also spoken with them and they seem to pretty "in the know" while I was on the phone with them. They have a 24 hour turnaround so shipping and all would only be around 3-4 days for two way plus the repair. Or I can drop it off and pick it up the next afternoon. At least it is finally something visible.
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#9
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Well, I got my ECM back on Friday and put it in. Got it to running temp and did an idle relearn. It runs fine now and purrs along except... I am now getting a P0420 code. Now to figure out if the cat is really bad. I have hooked up a scanner and my downstream o2 sensor is fluctuating just like the upstream, so I know there is most likely something happening with the cat converter. I am curious to see if I drive it for a while on the interstate and get it really hot, if the converter might do some "self healing" and clean itself up some. Didn't have the p0420 before the IAC went bad that started all this mess.
Last edited by acicomp; 01-14-2014 at 09:32 AM. |
#10
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I dont think the catalytic converter heals (if usually when the car is not running right when the catalytic converter overheats and is damaged)
running 91 octane will keep the keep the engine cooler |
#11
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Quote:
Code P0420 pertains to passenger side or left side when standing in front bumper. At bottom of the page is link to Engine-Codes.com. Simply click to open and enter the code in the search box. I suggests you make visual inspection to be sure you have no exhaust leak, intake air leak and inspect spark plugs. Also were the oxygen sensors or air fuel ratio sensors ever replaced. The oxygen sensors reading fluctuates from 0.1v Lean to 1.0v Rich as computer continually makes adjustment to achieve the ideal Air Fuel Ratio mixture. |
#12
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The p0420 code is new. It showed up after driving the car about 20-30 minutes. I am thinking it may have occurred because of the crazy idle that was taking place after the IAC was replaced. (Prior to the ECM being corrected) My scanner is showing the upstream sensor doing its job correctly in the voltage reading and the downstream is all over the place on voltage instead of remaining fairly consistent.
The car is running good besides the code being thrown right now. Cheapest Cat replacement around here is about $650 at a muffler shop or it will cost my right leg at Nissan. I am going to pull the plugs and double check them first. As well, I will pull and test the o2 sensor to make sure. Thanks Chris |
#13
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Meant to say "now getting a p0420 code"
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#14
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The frequency of the rich-lean cycling of the front and rear O2 sensors should be at an approximate ratio of 2:1 (front to rear) with the engine warmed up and vehicle driving at highways speeds if the catalytic converter is working efficiently. A 1:1 ratio would indicate the converter is not working efficiently. Some will put an O2 sensor spacer on the rear O2 sensor to "trick" the ECM and cause the code to not set. The spacer pulls the rear sensor partially out of the exhaust stream, so it still produces a reading, albeit an inaccurate one. If you have strict emission testing in your state, they will fail if they see the extender on the sensor.
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#15
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Tried the spacer and it almost worked. (For a day or two) Did a live scan and the readings indicated a bad cat. I picked up one yesterday and dropped it off at the exhaust shop to swap out. No joy! They called and were having problems getting the old one off and broke my exhaust manifold. Supposed to get part at 2pm today. Delayed again. Got a call about an hour ago and they will have it done tomorrow. Around 9 or 10 in the morning, I may go over and sit in their shop until they get it done.
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ecm, pathfinder |
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