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R34 Gtr 4wd/a-lsd Lights On

UnCo
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UnCo Rising Star

UnCo

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Hi guys & gals,

I'm getting an issue with my 34GTR where the 4WD and A-LSD warning lights are coming on the dash and the car is only running RWD.

It was thought that the PowerFC was faulty and the cause of the issues and so the stock ECU was put back in the car last week.

The issue seemed to go away and all was good until two days ago it started happening again.

So it seems the PowerFC wasn't the issue and now I'm hoping people here can help me diagnose the problem!

Things to note:

- I usually find out if the car will be 4WD or RWD when I first start the car. The light either comes on or doesn't come on within the first 2 seconds of starting the car.

- If it comes on then I can turn the car off and start it again until it doesn't come on.

- I've noticed that if I start the car and give it a bit of revs, then it doesn't happen.

- Sometimes in traffic when I decide to turn on the A/C or rear demister or even the headlights, it makes the 4WD/A-LSD light come on and then the car is in RWD again.

Battery is brand new, fitted 8 days ago, no voltage issues that I can see.

Does anyone have an Electronics Parts Guide that I can see the sensors to check?

Hoping to get to the bottom of this, it's frustrating :P

Thanks guys!

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paulr33 Grand Master

paulr33

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based on what youve told us so far id say TPS could be a likely culprit

both systems need the TPS signal (even at 0km/h) to run and pass diagnostics

if TPS is unplugged, broken, out of range, then the system fails and the lights come on

the TPS signal comes from the throttle body sensor

then runs into the main ECU harness into the main ECU

from here the ECU relays the same TPS signal onto another wire, which runs to the boot

and feeds into the 4WD/A-LSD computers. check the wire # on the engine wiring looms

ive seen my TPS go out of range and cause my A-LSD to fail like yours does

a known fix that I have seen (like yours) is to mash the accel pedal a few times

this manages to clear the out of range TPS signal and return it to normal state

TPS should 0.35v ish at idle (ie nothing on the pedal)

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UnCo Rising Star

UnCo

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Hey Paul,

I had a feeling it could be that.. the throttle sensor display has been rather irratic on the MFD (when I hold constant throttle at say 20% throttle, the display shows it jumping between 18-22% whereas if I hold the throttle at a constant in the TPS calibration, it stays steady)

Trent down at Status Tuning said that he was getting a TPS error code but when we ordered a new TPS from Nissan and put that in, it didn't have any changed effect?

So you mean try mashing the accelerator pedal when in idle or something?

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paulr33 Grand Master

paulr33

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check the actual wiring of it

with mine

if i boot the car up and drive around shortly after TPS goes to 0.00v

A-LSD and SLIP fail and the engine revs to 1500rpm and stays there (as it panics because TPS is dead)

so i turn the car off, mash the accel pedal a few times (to quickly open/close the throttle body) and then re-start the car and it's fine

if youve replaced the sensor, i would check the wiring

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