Replacing a ECU\ECM

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WVUMurray
Posts: 14
Joined: Wed Dec 24, 2003 5:38 pm
Car: 1997 Q45 BLack

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Hello,

I have a 1997 Q45 and I have a bad ECU\ECM. It sustained water damage and as a result my tach is not working and its throwing the speed sensor malfunction code. My mechanic was not able to locate a used one and I can't pass emissions without a new one. From a quick search online I see 1997 ECU's available. I believe that it is located under the passenger side kick panel. It seems fairly easy to replace. Am I off base here? I have searched quite a bit and found limited info. My mechanic was saying you have to have the exact number when replacing these and he couldn't find one. He is a good mechanic but not a japanese car expert. What would I need to know to ensure purchasing the correct ECU and is it very hard to swap in a new one? Do I simply need to match the part number on my current ECU when looking to buy a new one or is there more to it than that? I appreciate any help as this is becoming a giant pain as the car drives fine but just can't pass emissions.


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goody90q45
Posts: 3679
Joined: Wed Aug 17, 2005 2:07 pm
Car: 1992 Q45 (sold)
Location: Orangevale, CA

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There's 2 ECU's listed for the 97Q:
Fed 23710-6P100
CA 23710-6P600

You'll want to match ECU's. From what I recall reading, if you install a CA ECU in a FED emissions car you'll have an eternal EGR code that won't clear. Removal is very simple. Pull back the carpet square at the fwd corner of the passenger side kick panel and remove the 10mm nut. I'm not familiar with the 97Q but you may have to pull off the lower glovebox panel to pull off the kick panel. To get the ECU out remove the connector first before removing the screws holding the ECU to the chassis. There's no room to pull it out if it's still connected.

Before you rerplace the ECU....It is a faulty speed sensor that makes the tach and other cluster functions (speedometer?) operate. If it were me I'd do the speed sensor self-diagnosis sitting in the front seat in the comfort of my garage before I replaced the ECU of a car whose engine is running well. See the AT section (Page AT-23) of your FSM for the self-diagnosis procedure.

http://www.nicoclub.com/FSM/Q45/1997_Q4 ... Q45/at.pdf

WVUMurray
Posts: 14
Joined: Wed Dec 24, 2003 5:38 pm
Car: 1997 Q45 BLack

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Thanks for the info. The only thing is online all the parts numbers are listed as MEC-G150 or MEC-G130. I have a 150 which I believe is california from looking at listings.

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Q451990
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Car: 1990 Q45 - 118K, 2022 Toyota 4 Runner, 2004 Frontier M/T - 108K, 2012 Xterra (Mom's), 2023 Rogue (Inlaws)
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Have you checked www.car-part.com?

Heath

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goody90q45
Posts: 3679
Joined: Wed Aug 17, 2005 2:07 pm
Car: 1992 Q45 (sold)
Location: Orangevale, CA

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On my ECU/TCU list the manufacturer's P/N is blank for the 97Q but it's listed for almost every other Nissan and Infiniti.
The easiest way to verify what you have would be to pull the PS kick panel. The placard with the P/N will be visible on the face of the ECU without having to remove it. On the underside of the hood there will also be a placard showing the emissions diagragm and saying whether it's Fed or CA emissions compliant.

Do the speed sensor self-check first though.

WVUMurray
Posts: 14
Joined: Wed Dec 24, 2003 5:38 pm
Car: 1997 Q45 BLack

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Thanks for the car-part site. That is a great one.

Goody-

Yeah I remembered the emissions placard right after posting my last post and checked that. Definitely California. I did pull the kick panel previously and it is a Mec-G150. I found one for 140$. Not bad considering the shop was going to charge 500$.

Thanks for the help again.

STLQ
Posts: 6
Joined: Wed Jan 20, 2010 8:29 am
Car: 1997 Q45

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Where did you find your ecm? I have been looking for a BCM with no luck.

WVUMurray
Posts: 14
Joined: Wed Dec 24, 2003 5:38 pm
Car: 1997 Q45 BLack

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Got the ECM in the mail yesterday and installed it last night. The TCS came back to life the Tachometer came back on and the Check Engine Light went away. The car seems great again. It definitely runs a little better. I guess I just got used to how it felt with a partly bad ECM over the last year.

I found my ECM on Ebay motors but I would check the car-part.com site listed in this thread as well. They seemed to have a good number of ECms as well.

Thanks for all the help NICO members.

userpiks
Posts: 1
Joined: Tue Jul 15, 2014 6:17 pm
Car: 1997 Q45

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I also have a 1997 Q45, and I am having the same issue as far as water damage on my ecu/ecm. Did you find the source of the water? Also my car has begun to misfire from the #1 cylinder. My mechanic has ruled out everything mechanical and says the misfire must be caused by faulty ecu/ecm, is this plausible?


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