Hello!
I have a Seat ibiza 6L 1,4 BBY engine (same car as mk1 fabia) and I've had an issue lately (last few months) where the EPC light turns on suddenly when I start the engine with code P2101. The throttle works but only up to 2k RPM and the car seems to be in some form of limp mode. The moment I turn the engine off and on again it works like normal and the check engine light goes off after a hundred miles or so. When I return to the car and attempt to start it again I have the same issue. It seems to only happen when I start the car every now and then.

I did experience a weird problem a few weeks ago which has only happened to me once, while driving on the highway and attempting to accelerate from 50 to 60 mph or so the throttle stopped working completely and the EPC light came on again with the same trouble code. I had to coast to shoulder of the highway restart the engine and worked like normal.

Could a dirty throttle body cause these issues?

No, not dirty, it's either the throttle body itself or the pedal sensor, tricky to tell which without further diagnosis. My bet would be the pedal but it may be cheaper and easier to just buy a secondhand throttle body since there are tons available and see if the problem vanishes.

38 minutes ago, sepulchrave said:

No, not dirty, it's either the throttle body itself or the pedal sensor, tricky to tell which without further diagnosis. My bet would be the pedal but it may be cheaper and easier to just buy a secondhand throttle body since there are tons available and see if the problem vanishes.

 

But it's strange that the problem is so intermittent, you'd think that if the problem was pedal or throttle the issue wouldn't go away by just restarting the engine. Do you need a special VAG reader to code for a second hand throttle body or does the ECU adapt automatically?

18538 (P2106) - Throttle Valve Actuator Module (J338): Power Limited due to Malfunction

 

You need to be able to perform Basic Settings 060.

1 hour ago, Crasher said:

18538 (P2106) - Throttle Valve Actuator Module (J338): Power Limited due to Malfunction

 

You need to be able to perform Basic Settings 060.

 

Can you do it with one of these cables and free VCDS progam or do you need some type of expensive license?

2 hours ago, Carproblems said:

 

Can you do it with one of these cables and free VCDS progam or do you need some type of expensive license?

Only if registered, which is $99 to do.

See function chart here

http://wiki.ross-tech.com/wiki/index.php/Functions

Edited 15 July, 20232 yr by Breezy_Pete

It could be partly down to the throttle body being dirty, I had issues with mine and after having it cleaned I really noticed a massive improvement in the performance. I have also had the throttle sensor occasionally fail on me in a couple of VW Passat's, and was extremely scary every time it did so, it was while overtaking on a normal 2 lane road with another vehicle approaching fast in the opposite direction. Since I switched over to Superb's I have not had that happen, and I have had Superb's for longer than I'd had Passat's.

 

So it could be either or a combination of the two.

Since I've solved the problem I thought I would update the thread in case it might help someone else, turns out the issue was a dirty MAP-sensor.

 

I initially suspected the throttle body or gas pedal was the main culprit since it kept throwing up throttle body and gas pedal related codes. Since I got the car last year I would also occasionally get a P0106 code relating to the MAP sensor as well as the EPC light when driving, it would happen when I shifted from 4th to 5th gear and I lifted the clutch pedal too quickly, I didn't think these problems were related but I decided to investigate the MAP-sensor first as it tends to cause many idling and engine related problems. I removed the MAP sensor to take a look and it turns out that the MAP-sensor was completely covered in soot and carbon build up over the last 20 years or so which caused interference. I sprayed it with some electronic parts cleaner and the issue went away almost immediately, it took a few minutes of driving and couple engine restarts for the symptoms to completely disappear and they've not come back since. I did notice a slight improvement when accelerating as the car didn't surge and hesitate anymore when applying full throttle when joining the highway for instance like it did before and the idle feels a tad bit smoother as well.

 

https://imgur.com/a/j9ONN5w

Since the sensor was almost 20 years old I did replace it around a week later with a new BOSCH sensor since they only cost around 35$ on Autodoc. The new sensor has a different part number and a slightly different look compared to the old one as well (new 0 261 230 234 old 0 261 230 095) so likely this is an updated part, didn't notice any performance difference with the new one though so I believe the previous one was working fine once cleaned but I replaced it anyways.

I did remove the MAP-sensor quite recently to check for carbon build up and to my surprise there was none, it looked exactly like I had just installed out of the box so it seems that carbon build up isn't an acute issue, considering the low mileage this car has for the age it was probably not driven very hard where the engine reached operating temperature, probably city-driven for most of it's life which caused this. I use this car for commuting on mostly highways so carbon and soot will probably not be an issue (hopefully).

Since the MAP-sensor was completely covered in gunk I thought it's fair to assume that the rest of the intake manifold, throttle body, EGR and PCV system is also covered with the same stuff so I initially thought about removing everything and giving it a thorough cleaning but since the car is almost 20 years old I decided against it since removing all of it is quite an involved job and replacing broken and brittle plastic components would be a major hassle, especially the intake manifold. I ended up just cleaning the throttle body.

The throttle body was completely covered in caked-on carbon deposits, I tried to use various solvents and degreasers like brake cleaner, electronic parts cleaner, acetone, white spirit and even oven degreaser to no avail. The carbon had basically solidified on the surface and it was essentially flaking off, I ended up just using a wooden tooth pick to scrape off as much carbon as possible, primarily around the edge of the butterfly valve where it contacts the housing and the shiny coated surface around the valve. I reinstalled it on the car and the engine was throwing all sorts of codes and the idle was all over the place, so I readapted it with VCDS. The idle is now almost buttery smooth and I feel a slightly better response from the engine when driving.

These are pictures of the throttle body after cleaning it, forgot to take before pictures. As you can tell I didn't bother making it sparkly clean, only the coated shiny surface and the edge of the valve. Also I took a few pictures of the EGR pipe, looking at the way it's pointed upwards, no wonder the back of throttle body was covered with rock hard deposits. Brilliant design.

https://imgur.com/a/HQNThzh

Edited 27 October, 20232 yr by Carproblems