Gearbox fault

4.2 V8 40v biturbo - 450 bhp
4.2 V8 40v biturbo - 480 bhp (plus)
Frazz82
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Gearbox fault

Post by Frazz82 » Wed Nov 30, 2022 3:30 pm

Any idea what could be the cause of these codes. One came on Monday morning an one this morning cleared them an they stayed off for now. The temperature has dropped this week and wondered if it could be this an the fact the cars been stood afew days.

Gearbox was serviced and loom changed 12k ago.
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Shoppinit
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Re: Gearbox fault

Post by Shoppinit » Wed Nov 30, 2022 3:42 pm

Could be:

Corroded contacts in the plug to the gearbox
Corroded contacts in the plug to the TCU (suggests water ingress - check under carpet insulation for damp)
Failing TCU
Bad harness inside gearbox

Could even be the thing to which the fault code refers, the N215 solenoid valve.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Frazz82
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Re: Gearbox fault

Post by Frazz82 » Wed Dec 07, 2022 11:14 pm

Got under the car tonight. Looks like the plug to the gearbox was loose the locking clip wasn't fastened fully so I pushed the plug in and tightened the clip. So I am hoping this is the cause as I really can not be arsed with a massive issue at christmas time 😁

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Shoppinit
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Re: Gearbox fault

Post by Shoppinit » Thu Dec 08, 2022 7:10 am

Could well be. Fingers crossed.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Frazz82
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Re: Gearbox fault

Post by Frazz82 » Tue May 02, 2023 1:00 pm

This has started playing up again but intermittently if I start the car up and it flashes up gearbox malfunction I find running through the gears turning engine off and again sometimes works. I checked the plug again and thats tight and I am going to service the gearbox as I did 10k ago with anew filter and harness which I may replace again if it looks bad. Would it be worth replacing the faulty solenoids while sumps off as a precaution.

I also want to check the TCU is it located under the (UK) NSF carpet and is it easy enough to get at.

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Shoppinit
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Re: Gearbox fault

Post by Shoppinit » Tue May 02, 2023 1:01 pm

Same fault code?
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Frazz82
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Posts: 235
Joined: Thu Jul 18, 2019 9:59 am

Re: Gearbox fault

Post by Frazz82 » Tue May 02, 2023 1:43 pm

18243 and 18228 are both coming up together each time the intermittent gearbox fault flashes up.

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Shoppinit
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Re: Gearbox fault

Post by Shoppinit » Tue May 02, 2023 1:52 pm

I suspect a contact problem rather than a problem with the solenoid valves. I guess it depends how expensive they are. My feeling is that the harness will resolve the problem, but if you've had corrosion on the pins then that might never make a good connection. Have a good look when you replace the harness.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Frazz82
2nd Gear
Posts: 235
Joined: Thu Jul 18, 2019 9:59 am

Re: Gearbox fault

Post by Frazz82 » Tue May 02, 2023 3:29 pm

Is the TCU under the drivers carpet I am just wondering if my wet carpet could be causing the issue.

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Shoppinit
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Re: Gearbox fault

Post by Shoppinit » Tue May 02, 2023 3:31 pm

It’s under the passenger side IIRC but if it’s wet on one side it’ll almost certainly be damp in the other.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Frazz82
2nd Gear
Posts: 235
Joined: Thu Jul 18, 2019 9:59 am

Re: Gearbox fault

Post by Frazz82 » Sat May 06, 2023 10:07 am

Cheers for that will get under there and see what it looks like.

From your experince if I am getting the same solenoids coming as a fault could it be the tcu thats at fault.

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Shoppinit
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Re: Gearbox fault

Post by Shoppinit » Sat May 06, 2023 10:24 am

Could be solenoids or the wiring or the TCU. Not very likely that it's the TCU but it's not impossible.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Frazz82
2nd Gear
Posts: 235
Joined: Thu Jul 18, 2019 9:59 am

Re: Gearbox fault

Post by Frazz82 » Sat May 06, 2023 2:53 pm

I lifted the passenger side carpet but all that was there was the something called the comfort module 4bo962258n also carpets bone dry.

Could the tcu be under the drivers carpet ? This may tie in with the water ingress I have on thst side which I think is either the bonnet cable grommet or maybe the ECU plastic box where it bolts to the scuttle.

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Shoppinit
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Re: Gearbox fault

Post by Shoppinit » Sat May 06, 2023 2:55 pm

OK, then it's the other side. The TCU is the opposite side to the comfort module (which does your central locking).
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

User avatar
Shoppinit
Cruising
Posts: 20318
Joined: Wed Dec 31, 2008 6:24 pm

Re: Gearbox fault

Post by Shoppinit » Sat May 06, 2023 2:56 pm

If there's water ingress, then you want to get the TCU out of there before permanent damage is done. They're not cheap (or easy to find).
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

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