Per4mnc

My wife and I purchased a 07 350z with the vq35hr. Loved it. One day driving vdc light came on along with slip and check engine light. I was a Ford tech in the past. So I break out my handy scan tool. Read a code for p2135 sensor b1. So I figured I can do that easily enough. Disconnected battery and replaced both throttle bodies. Decided while I'm here let's change pedal assembly with a new sensor just in case they are in the same system. Reconnected battery and the pedal learn and the idle air relearn for the throttle bodies. Car ran great for 12 miles. Then the slip light, vdc, and check engine came back on as well as limp mode again. Perplexed I took it to nissan. They scanned it and said bank b throttle body was bad. Hard to believe but I have purchased parts that were defective. Took the throttle body back under warranty and got a replacement. They were Hitachi brand which was an oem manufacturer. I thought since Nissan has the car let them replace it and do all the relearning steps. Picked up the car and made it a mile before it came back on. Took it back to Nissan. Master tech says it's the same code. He clears the code and puts the car through 4 drive cycles totaling 28 miles. Says car isn't showing any symptoms or throwing code. Pick it up and drive it 60ish miles and all the lights that came in before come on again. Take it back. They call the nissan tech line and look for loose and corroded wires. None found. Did a continuity test of all circuits no faults. They can't get it to throw the code once cleared. So 700 dollars later I pick up the car again. I was told tech line recommends replacing wiring harness but they are not made anymore and to go through the wiring would be at least 1200 dollars if not more. We are at the end of our rope. I looked on all the forums but have not found another case that it was a persisting problem. Most people get throttle replaced and never had another issue. We love the car when it runs properly. Just don't know what to do next. I don't want to dish out 1200 or more and not have a guarantee that is fixed. Anyone else even know of anyone that has had a problem like this? Sorry for the long winded post.

i8acobra

iTrader: (6)

I would try swapping out the ECM. When I was a Nissan Tech, I had a few good ECM's in my toolbox. If I had a code that kept coming back, I'd swap out the ECM, go through all of the relearns, including the keys and then drive the car. You'd be surprised how often that fixed the problem. ECM's are so complex now, a single cold solder or cracked solder on the board could cause a single code. I don't know how you're going to do it without buying an ECM though. Don't spend a bunch of money on a guess. Know anyone with an '07 or '08 Z who would let you borrow theirs? You'd still be out some money to have it learned to your car and then back to their car though.

dkmura

iTrader: (64)

Welcome and sorry to hear of this problem. I've had a similar story with my 350Z (HR-powered) racecar and have detailed parts of this sordid tale in a long thread:

2020 SCCA Runoffs - MY350Z.COM - Nissan 350Z and 370Z Forum Discussion

I consulted Nissan experts from coast-to-coast and lost thousands of dollars in the attempt to get my HR up and racing in 2020. Worse, I bought a second ECM in an attempt to repair the problem, but found it suffered the same fate. We've gone through the wiring harness this winter and not found any apparent issues. The best I can say is this problem has taken my best efforts and humbled me. A Z racecar that won't run at WOT isn't much of a racecar.

Per4mnc

I dont have access to an ecm without buying one. There is a local lkq in town and could get one from a g35 with the HR since there are a ton in their lot. Dont know if there would be any weird issues like being an auto ecm. I know the K24 swap I did in my integra I didn't do all my research and bought an auto ecu that would not work at all and had to spend a little more and go buy a type s ecu. Thanks for all the advice. Like I said earlier when the car works its a wonderful car that handles like its on rails and so fun to drive. On another note there is a local shop in town that specializes in Nissan products that I contacted who said he could help pin point the issue even more. Since he works on r32, r33, 350z, and 370s in a performance aspect and does wire harnesses I might just let him take a crack at it.

dkmura

iTrader: (64)

You'll need an ECM with preferably the same code and type that's in your Z. Mine was 23710-EV12C (HR powered Z33 with 6-speed) to interface with all the systems on your Z. Have you pulled yours to check on the part #? What's the name of the Nissan specialist who can work on ECMs?

Per4mnc

Sorry for the late reply. Work has been killer. My wife actually works for a defense and aerospace company and can test all the components and check the solder joints and connections. Thats her specialty. I'm looking into another ecu just in case. I have not pulled the ecu yet, still waiting on free time. The name of the shop is in Huntsville Alabama. His shop name is midnight auto. Cliche in my book but every nidsan enthusiast in the area swears he is great on Nissan. Hopefully it gets resolved soon, my wife is at the point she just wants to sell it. It is her car and I can't blame her, but you can see the sparkle in her eyes as she is rowing gears and I'm trying g to talk her out of it. Thanks for all the help gentleman.

dkmura

iTrader: (64)

Thanks for the update. Have you ever pulled an ECM before? Do you know where it is, or how to safely pull it? I'd be interested in what your wife's company could find with it.

esqueda_

Hi, did you ever get this fixed? I may have a similar problem and cant find the solution yet.

bealljk

iTrader: (13)

I would consider replacing the electrical harness with a decent used one.

I’d also check your grounds on anything and everything you can get a volt meter on.

Does this car have any aftermarket anything? Headslights? Brake Lights? Radio/Subs/Amps? If so I would swap those back to OEM (if possible) and/or disconnect the power supply.

If you haven’t already check that your alternator is pushing 14.4 to 14.6volts