Audi A4 2008 (new shape 08) CVT auto fault "shift solenoid n88" fault Help

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akersgarage

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Hello wondering if anyone can help me out. Or had experience with same issue

I have a 08 plate 1.8T petrol Audi A4 (first of the new shape)
It has the CVT auto gearbox

Comes up with fault P0750 shift solenoid 1 N88 malfunction intermittent

It had a gear oil change a while back by ourselves with correct oil from audi (not done a lot of miles since)
I checked the oil condition and it looked fine, no metal etc in oil

I was convinced it was the auto box control unit it at fault, had similar issue with the older shape audi.
So I sent it away to be checked/repaired by a repair company we have used in the past
Unit came back this morning with a report saying all is well. No repair done , no fault found

The actual car fault is: auto box selection number lights flash and it wont drive when 1st selected. Switch it off and it sometimes can select and drive perfect till next morning.

I don't have a fault log print off at hand because the car is in pieces just now and auto unit just back in box.


Anyone else replaced the control unit or had them repaired.
the fact the fault is intermittent, says to me the unit is still at fault but when repair company tested it was working ok.

Thanks
 
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Keithuk

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When you have a problem/query you ALWAYS post a full AutoScan of the vehicle in question, whether there are any error codes or not. There is more useful system info in there, how the car is equipped and configured. How to post an Auto-Scan

There is nothing on Ross-Tech Wiki. You can Google this code, what I have:


VAG Error Code: 17134/001872
EOBD II Error Code: P0750

Fault Location:
Shift Solenoid Valve 1 (N88) - Malfunction

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Transmission will not shift gears.

Wiring/Connector(s).
Low transmission fluid level.
Dirty transmission fluid.
Shift Solenoid Valve 1 (N88).
Engine Control Module (ECM)/Powertrain Control Module (PCM)/Transmission Control Module (TCM) (J217).

Tech Notes:
When the a transmission solenoid is malfunction, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is very dirty, it is recommend changing the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a transmission mechanical failure and that the transmission will need to be rebuilt or replaced.

When is the code detected?:
The P0750 code is detected when Transmission Control Module (TCM) detects an improper voltage drop when it tries to operate the solenoid valve.

Description:
Shift Solenoid Valve 1 (N88) is turned ON or OFF by the Transmission Control Module (TCM) in response to signals sent from the park/neutral position (PNP) switch, vehicle speed and Engine Control Module (ECM) (throttle opening). Gears will then be shifted to the optimum position.
 
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akersgarage

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Just a quick update on this problem incase any one comes across the same.
The Auto box control unit was removed and sent away for repair as said previously, but the company said it tested ok so we were stuck with their invoice for £81 and no further forward.

We took a gamble and purchased a brand new control unit from Audi which has now fixed our problem. Car is now shifting/selecting gears perfect. No more faults in auto box control unit.

Only slight issue, was the new unit which came from Audi.....once fitted and coded to the car had a fault logged "control unit locked" so we had to trailer the car to Audi to have this lock removed After that car drove perfect.
 
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Jack@European_Parts

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Just a quick update on this problem incase any one comes across the same.
The Auto box control unit was removed and sent away for repair as said previously, but the company said it tested ok so we were stuck with their invoice for £81 and no further forward.

We took a gamble and purchased a brand new control unit from Audi which has now fixed our problem. Car is now shifting/selecting gears perfect. No more faults in auto box control unit.

Only slight issue, was the new unit which came from Audi.....once fitted and coded to the car had a fault logged "control unit locked" so we had to trailer the car to Audi to have this lock removed After that car drove perfect


FOD........double jeopardy!

That is the difference between a real rebuilder & which has the ability to simulate the car identity to test a module for function or security........and a testament to true upload/download value.

Don't trust the flyby night place that works on the cheap.........

Thanks for reporting back OP......

JPPSG for FOD
 
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