Jetta 5 1.6 deCAT

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Jetz
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Jetta 5 1.6 deCAT

Post by Jetz »

Hi everyone

I just had my Jetta 5 1.6 deCAT (not for performance). The car struggled to start and when driving I could barely hit 100km/h with only me in it.
I didn't want to do it, but it kind of had to be done at the same time.

When the mechanic starts the car the Revs jump around and the EPC light comes on, then the revs stay steady but the light stays on.
The car is at the mechanics' still, he said they have tried clearing the error but it comes back (not sure what software they have).
The error code reads as follows:
17579 - Angle sensor 2 throttle actuator; implausible signal - permanent


The throttle body was changed by me two years ago.
I know the throttle body is not the issue because, before deCATing, the EPC light never came on.

I do have a Carista subscription and could clear the code on the app, but its probably the same as what the mechanic is doing.

Any ideas as to how I can fix this?
Or is there a place where I can have this coded out?

Thanks in advance
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amstel18
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Re: Jetta 5 1.6 deCAT

Post by amstel18 »

Don't try and mask a problem, rather fix it.

How was the decat done? Was the CAT cut out and a new pipe welded in?

Could be that in the process, there was some damage done to the wiring going to the Throttle body.

Things like this happen, by accident, Jetta 5 is getting old, and wiring becomes brittle.
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Re: Jetta 5 1.6 deCAT

Post by missioner »


Jetz wrote:
The throttle body was changed by me two years ago.
I know the throttle body is not the issue because, before deCATing, the EPC light never came on.

Thanks in advance
See now this is something I very much try to not do.

Is the vehicle wiring 100%?
Has the ECU not been damaged by bad diagnosis? Has the continuity been tested from the throttle to the correct pins on the ECU?
Has the live data been recorded related to the performance of the throttle?

If you answer no to one or more of the above, the statement regarding the condition of the throttle is false.

Besides that a decat will only give you O² sensor faults generally.

The code you posted literally means the Engine Control Module says the throttle is not making sense and it can't trust the information provided by the throttle to run the engine according to driver demand.
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Re: Jetta 5 1.6 deCAT

Post by missioner »

Try cleaning the throttle and replacing the airfilter.
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Jetz
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Re: Jetta 5 1.6 deCAT

Post by Jetz »

Sorry for the delay in response. So I got the car back last Friday. The mechanic did some tweaking on the throttle values or something . Anyway no EPC, and the car feels amazing. Totally different. I have driven it on a long drive yet, but I did take it on a quick highway run and was able to continue accelerating uphill after reaching 130 km/h even. Which is like a day and night difference to before. Before on the same uphill my car would drop to 80 from 115 by the time I reach the top of the hill.

Fuel economy also seems to have improved a fair amount, but since I haven't driven it for more than an hour yet I can't say. Will report back on that once I have.

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