DipreSantana

I've had this issue for a while, I made a thread, but it was quickly derailed.

So my car won't rev past 2.8K, unless I turn it on, turn it off, and turn it on again quickly. If I do that, it will drive normally till the next time I turn it off.

The SES light is on, and it points towards the EGR valve, which I replaced, and I also replaced the MAF. But I'm still having the same issue.

After some research I came upon this.



Anyways, the inspection expires this month, and I need this fixed fast, has anyone had this issue and resolved it?

DennisMik

iTrader: (2)

There are several things that cause fail-safe mode, or as others call it, "limp-mode". Usually the check engine light comes on for most of these reasons. The MAF is something that may or may not trigger the check engine light.

Exactly what is the code you currently have for the check engine light? IIRC, the ERG won't cause limp mode.

DipreSantana

I'm getting code P0400. I'm sure it's the EGR, but the wiring, not the valve, if I were to rerun these cables, where would they lead to? The ECU?

DennisMik

iTrader: (2)

When you replaced the EGR valve, did you check/clean out the tube that runs between the EGR valve and the cylinder head? This tube does get completely plugged up and can also cause the P0400.

Otherwise, 4 of the 6 the wires on the EGR do go to the ECU. The 2 solid red wires in the center of the connector have 12 volts that comes from the ECM relay and the ENG CONT 1 fuse in the fuse box by the battery. Running new wires is a pain, so check the continuity of the wires first.

See page EC-417 for the EGR valve connector and ECU connector pinouts.

http://boredmder.com/FSMs/Nissan/Maxima/2000.5/EC.pdf

DipreSantana

So I had the EGR replaced again, the wires checked, and a ton of other stuff checked, and the problem still persists. The mechanic has told me the last thing to do is swap out the ECU.

DennisMik

iTrader: (2)

I would swap out the mechanic.

Another org member said that he went to a Midas Muffler shop where they had a machine that actually tests the MAF. I don't know if all Midas shops have that MAF tester, but talk to them.

DipreSantana

The mechanic has ordered an ECU, I told him if the ECU didn't resolve my issue, I wasn't paying him, he agreed.

Would the MAF cause the EGR code to post?

DipreSantana

So I had the ECU replaced on the vehicle, the problem still persists. Now the mechanic tells me the only thing left is to check the harness wiring going form the ECU to the EGR to see if there are any shorts. As I stated before, he did not resolve my issue, so I won't be paying him for the ECU swap.

If what he says is true, then I can just run all new wiring from the ECU to the EGR, but could a short on the harness wiring really be the issue?

DennisMik

iTrader: (2)

You can replace any part on the car you want to, any time you want to, for what ever reason (if any) you want to.

I think this mechanic has no credibility. You believed him that a new ECU would fix your problem. How did that work out? Now you want to believe him that the wires are bad?

It's just that it is very rare for wires to go bad unless there has been human intervention involved. If you suspect wiring problems, do a continuity test first to find out if the wire is actually bad.

Was the tube that connects to the EGR valve ever cleaned out to make sure it is not plugged up? This can cause the P0400. This tube connects to, but is not part of the EGR valve.

The P0400 code can also be caused by the EGR temperature sensor.

DipreSantana

Thank you. The error is actually P0403 now. And I had another mechanic check the continuity, all the cables are fine. The previous mechanic says he cleaned the tube, but IDK, I might check that myself, I'll see about the EGR temp sensor.

DennisMik

iTrader: (2)

The EGR temperature sensor is listed as a possible cause for P0400, but not for P0403. Maybe it could cause the P0403, but I don't know.

colt149

iTrader: (1)

I have the same issue before, I have the SES light and the car was on limp mode. My mechanic told me that the code is referring to the throttle valve. (OBD Scanner used is the Snap ON ). The Throttle valve was replaced but the problem persist. What I did I purchased another Throttle valve assembly at courrtesyparts.com and my vehicle was placed in Nissan OBD (Consult II)
Problem was solved. You need the original Nissan OBD Scanner (Consult II) to fix delicate code error's

importworx

I have a very similar issue but on a 05 maxima. let me know if you find the issue so I can try this too, im out of ideas. I was thinking the ECU but I highly doubt thats the problem on mine as well.

DipreSantana

I took my car to Nissan, they scanned it, and gave me a $3800 + labor estimate. They said I needed to replace the IACV valve, the ECU and the engine harness.

4thGenTuner

iTrader: (1)

My god. I don't think the car is worth that.

What trim/trans do you have? GXE, GLE, or SE? Auto or 5 speed?

You should look into if you have the electronic motor mounts. It will be easy to spot them due to the harness and plug. They will be the front and back torque mounts.

If you do have these electronic motor mounts and have an auto trans, UNPLUG THEM NOW!

DennisMik

iTrader: (2)

If the motor in the IACV shorts out, it may cause transistors in the ECU to short, but rarely does the wire harness go bad. The prices at the dealer are very high, both parts and labor.

If the ECU is damaged, it can be repaired for less than $200 instead of replaced. The IACV prices at auto parts stores vary between $200 and 350.

The only part that I don't understand is that the IACV usually causes a P0505 code.

DipreSantana

I have a GLE 5 speed.
It was a BS quote, I only have 1 error code, and everything that's related to that quote but the harness has been repaired. Instead of doing the diagnostic work to figure the issue, they decided to go ahead and replace everything but the engine block.