All P's and U's

mannyz

Greetings everyone,

As some of you know I came back to the Z community after I purchased a used 2010 Z. Exited to relieve the great memories I had with my old 2009 Yellow Z. Sadly this MOFO car tricked me as well as the dealership (but maybe the dealership didn't know). When I test drove this car, the only light on the dash was the AirBag, which story very short I fixed with an adapter for the seat cushion sensor. Problem Solved. Happy Owner. Then it was cosmetic stuff.

Now the MOFO car, have all kind of issues. I found those common problems here and while the forum has been a great help, nothing had worked. I even took the car to two different mechanics and they cannot figure it out what is the problem. So I am not in the position of either continue putting money to a ghost problem or just get rid of the car.

What are the problems.

- My first problem was when the car went limb mode on me with a check engine. Couldn't go over 1000rpm. Check the car and it came up with P0300 and other related to to VVEL. Thanks to the forum I dig around and found a blown relay which I replaced. Problem solved.

- Then out of nowhere a check engine with a shake lazy engine. This time the car runs but you can tell it just not running right. P0300 Code again, U1024 and P1606. Again thanks to the forum I ordered a used VVEL Module and installed it. Cleared computer, worked fine.

- Few days later the same problem. At this point I went ahead and replaced the battery, installed new Z1 Coils, new Spark Plugs, new camshaft sensors, cleaned and rebuild fuel injectors, installed OEM intakes (car had short rams). Cleared codes and worked fine.

- Then again, this time I get the limb mode again. So I took it to a mechanic that says he think it could be a bad O2 sensor but he needed time. 2 weeks later they called me to pick up the car and test drive it because they test it and is running fine. $250 later, I picked up the car and noticed on the invoice that all they did was reset the codes and disconnect the battery. So you know what happened next.

- Few days past, and limb mode again, cannot drive the car pass 1000rpm. Ran the code and now I got a new one P2101.

So even after all the parts replaced here is the list of codes:
- P2101
- P0300
- P0305
- P1060
- U1024

Of course I don't trust stealerships but I decided just to stop by and explain the problem. And obviously their solution after I heard all they told me is getting a new car because their answer was: Well it could be any sensor, wiring, ECU, but since you have some mods installed, the best thing is to put the car back to stock and start from there. Which of course I said

"Help me, Obi Wan Kenobi. You're my only hope"

After this, the car goes for sale, If I cannot fix it.

Thank you all

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SLOPOS

Posted before reading your other threads on the matter. Was the car sold as salvage by chance? It sounds like the harness may have been pinched or maybe you got a critter I'm there eating away at your wires. Electrical issues can be a beast to figure out - if the two mechanics didn't have luck it's going to be hard to diagnose over the forum.

SonicVQ

Most of your codes point to the VVEL system. The U1024 has the highest priority and should be looked into first.

The VVEL communicates to the ECU on a dedicated CAN bus. The easiest CAN bus check is to measure the resistance between CAN H and CAN L and it should be around 60 ohms.

The 1,000 RPM limit is the fail-safe for the electronic throttle and that relates to the P2101

If that was my car, I would examine VERY carefully all the wires related to the VVEL system and the throttle bodies. Unplug them and check for corrosion or bent pins, then plug back in.

After that my next step would be to scope the throttle body position sensors, VVEL power/grounds and the VVEL CAN bus to verify a proper signal.

Since most don't have a scope, a multi-meter will allow voltage checks.
If you don't have a good understanding of electricity/meter use, you might want to find mobile tech that has these tools and Nissan/Infiniti experience.

How did you determine the VVEL relay was "blown"?

mannyz

Honestly I don't know, I purchased the car in one of those Buy Here small dealers. I do heard from the guys who sold me the car that the owner go and purchase cars from an auction, so who knows, maybe it was. I did checked the VIN and while the car had accidents, the CarFax didn't showed as totaled or salvage. So I went based on that.

Thank you for your opinion.

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mannyz

Thank you, definitively I don't have any knowledge or experience in electric or ohms. That will be a job for another person.

For the relay I read here in the forum about that problem and some people mention to check the VVEL Relay. So when I opened the box and found the Relay I noticed that it was blown. So I though that would have fix all the problems. But it seems the car has more than one issue. Thank you for the codes clarifications.

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mannyz

OK guys here we go, let me give you an update. I was ready to discard the car and sell it. Just reset the computer and sell it. But stupid me I decided to take it to the dealership thinking that they have the tools and knowledge to find out what the heck is wrong with the car.

Well after I explained what is wrong with the car and what I have done to the car already, and argue with the mechanic. They took the car in and told me that they need at least 2 hours of diagnostic and that will be $500 which I agreed. But I always had this hint in my head that the previous owner may have done some tuning to the car, so I ask them that if they cannot find what is wrong with the car to go ahead and reflash the ECU or ECM.

A week later they called me telling me that they went through the Nissan list and everything I replaced was part of the to do list (which was my previous argument with the tech) so they skipped all that, and they check the harness which came out fine and that the only thing left was the ECM, but they cannot access the ECM, they told me the ECM was defective. So they quoted me a used ECM for $3,000. Of course I told them I am not spending $3k on that car.

So I went pickup the car with the idea that I will clear the codes and sell the car (sorry for the next owner). Brought the car back home and spoke with a friend of mine that used to tune Mitsubishi cars. He also was thinking there was something wrong with the ECM, maybe it was tuned and locked from modifications. So he found me a used ECM for $100 (not $3,000).

I installed it, then he called a Lockemisth for me that will link the key to the new ECM for the immobilizer and guess what. 3 months later and I have no problems. I've been driving the car to break it and throw codes and everything is working fine. I am happy again and now I can continue with my projects on the car.

So for those people with these type of codes and that already replace coils, VVEL Modules and stuff, if you purchased a used 370Z maybe try reflashing the ECM, if not get one from another vehicle.

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vtec to vvel

Where did you purchase the car? Any reputable dealer will have (or should have) resolved any issues before putting up for sale and shouldn’t see any lights when test driving.

While a Carfax is a great tool, it should only be used as a guide as it will not have everything listed on it sadly. For example, if there was major damage and the previous owner decided to fix themselves, it wouldn’t it make it to Carfax. Also, even if a dealer/mechanic fixed, they don’t always report to Carfax.

For limp mode, did you try cleaning the TB’s and O2 sensors? Even if the code didn’t appear, it’s well worth the try, esp. on a 2010.

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projectpanda

It seems the fix was the ECM.

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RHM 75mm TB & ported up/low mani., 3" intakes/velocity stack, Z1 Headers, Motordyne ART pipes, HBP 3.5" exhaust, Tein MonoSport, SPL F/R arms, endlinks, and tie rods , Eibach sways, Z1 rotors F/R, diff bush., subframe collar, Bell Raceworks diff brace