csavino3

Recently, my car was driving on the freeway and went into limp mode. The dealer ran the ECU codes, found the throttle body at fault, and replaced it (cost me $1K, but that's another story). Straight out of the dealership, the car goes limp again. I've taken it to 2 other shops and reset the ECU twice, limp mode returns consistently after about 1 week of driving. SES light comes on, and can't rev it above 1K; turn it off and on and I can barely get home.

I'm taking it into the shop again, and have some questions that I hope this forum can answer:

1) Should I consider removing the aftermarket CAI? I have a feeling that it may be affecting the MAF and causing the ECU to freak.

2) Should the ECU have been re-flashed after the initial TB work? Might it not be used to all of the mods on the car?

3) Are ECU error codes store after a reset? I reset the ECU on Friday, after it went limp on me again (to get it home). Will the shop be able to determine fault now, or do I have to wait until it happens again?

Here are a list of the (known) mods...any other root causes I might be missing?

Borla cat back
High flow cats
Crawford plenum and strut bar
350evo sway bar
Tein coilovers
K&N
grounding kit

Thanks in advance.

Netko350Z

iTrader: (8)

find out what caused the SES light to come on. There is a code that will read out and will help you pinpoint what the cause was.

Just but a OBD II code reader and let us know what code number it threw.

csavino3

Okay, I'm taking it in tomorrow, and will let you know.
One more question: it appears as though I have two different size tires on the front: 225/45/18 on the left and 245/45/18 on the right. This wouldn't be causing it, would it?

HighwaySpeed

245/45/18 is a rear tire size! Check both of the rear tires too!

P225/45WR18 (front) and P245/45WR18 (rear) high-performance tires

csavino3

I replaced the rear two; they're okay. I just never noticed that the front two were mis-matched.

Speedracer

Recently, my car was driving on the freeway and went into limp mode. The dealer ran the ECU codes, found the throttle body at fault, and replaced it (cost me $1K, but that's another story). Straight out of the dealership, the car goes limp again. I've taken it to 2 other shops and reset the ECU twice, limp mode returns consistently after about 1 week of driving. SES light comes on, and can't rev it above 1K; turn it off and on and I can barely get home.

I'm taking it into the shop again, and have some questions that I hope this forum can answer:

1) Should I consider removing the aftermarket CAI? I have a feeling that it may be affecting the MAF and causing the ECU to freak.

2) Should the ECU have been re-flashed after the initial TB work? Might it not be used to all of the mods on the car?

3) Are ECU error codes store after a reset? I reset the ECU on Friday, after it went limp on me again (to get it home). Will the shop be able to determine fault now, or do I have to wait until it happens again?

Here are a list of the (known) mods...any other root causes I might be missing?

Borla cat back
High flow cats
Crawford plenum and strut bar
350evo sway bar
Tein coilovers
K&N
grounding kit

Thanks in advance.

It is very easy to scan the OBD II port and do a simple diagnostic of which code was thrown.

Likely culprits are you cats/oxygen sensors or the MAF sensor. If the MAF sensor gets oil residue on it from an oiled aftermarket filter, it can definitely go into limp mode.

Tires won't cause this problem, but obviously they are on wrong.

csavino3

Would the MAF go wonky from an oiled aftermarket filter 3 months after I changed the oil?

Netko350Z

iTrader: (8)

Possible if it took the oil that long to build up.

Speedracer

Yes, a change in the composition of the oil on the surface of the MAF over time, or the adherence of fine particles that get through the filter could, over time, do this. Happened to a friend of mine on an Audi S4, although his time frame was about a month. Also, check the wires coming from the MAF. Make sure they did not get damaged in any way.

raycs7

iTrader: (42)

Had this issue once on my roadster.
After resetting the ECU the third time, I removed the intake back to the TB [which I had removed several times prior].
I then reconnected the system, taking care there were NO air leaks at the gaskets and the clamps were properly secured.
I have not had a problem with it since.
BTW:I had the JWT charger installed. Hope this helps..

WATSON1

I over-oiled the filter on my Nismo CAI on my Altima a while back, and it caused my MAF to blow, resulting in limp mode. Have the codes pulled, that should tell you the cause. Most any auto parts store will pull them for free.

csavino3

It was throwing a TPS code, so the guy spent some time looking over the ECU. Apparently, the wiring into the ECU had been shrink wrapped and had become loose. He remounted these wires, relearned the throttle position through the ECU, and proclaimed it working again.