a6 3.2l throttle body issues / going to safe mode

[estomax]

my 2007 a6 3.2l with 252k miles has been giving me throttle body headaches for the last 6 months or so. I started getting random ESP/Traction control lights turning on the dash and the car cutting power to near zero (though still able to hold about 35-40 mph) no matter what the gas pedal position is.

P0121 - Throttle/Pedal Pos.Sensor A Circ. Range/Performance Implausible signal
Intermittent
P0221 - Throttle/Pedal Position Sensor/Switch B Range/Performance Implausible signal
static
P1545 - Throttle valve control system Malfunction Implausible signal
Intermittent

In september i replaced the throttle body with a $150 one from rockauto. Things were fine until November when i started getting codes again. I suspected the new throttle body was too cheap/shitty so I warrantied it and bought a 400$ bosch unit. The Bosch unit was fine for another month until now and i started getting codes/cut power again. Though this week the power cut was less severe, i can accelerate up to about 60 right now, but it feels like doing so at 10%-15% throttle.

Some more research is pointing to a possible harness issue? this TSB I came across:
https://static.nhtsa.gov/odi/tsbs/20...24818-9999.pdf

Before i go and buy an official Audi throttle body, i think i will try to do the TSB above... but looking for any thoughts from you guys that may have been through this.

Cheers for your 2c,
Marko

[MTL4]

I agree that sounds more like a wiring harness issue than the throttle body itself. It’s likely the harness because it looks like every TB sensor is having issues at once and you can see they are all intermittent problems.

Have you used a VAGCOM or similar to actually look at the output for the position sensor and the throttle valve control? You may be able to have someone wiggle the wiring (both engine on and off) while you look at the output and then have them take it for a test drive while you watch the outputs from the copilot seat.

[G-Can]

I kept having same issue. Happened two or three times, but as I have a Carista OBD2 dongle in the car allways, I would pull over, reset the codes and continue.

then took it to mechanic that did throttle body cleaning a yer ago, and he re run the throttle body adaptation (did you do this when you repalced them? )

and ever since then its been driving flawless. Saying this, now its probably gonan die today. :D

[estomax]

I kept having same issue. Happened two or three times, but as I have a Carista OBD2 dongle in the car allways, I would pull over, reset the codes and continue.

then took it to mechanic that did throttle body cleaning a yer ago, and he re run the throttle body adaptation (did you do this when you repalced them? )

and ever since then its been driving flawless. Saying this, now its probably gonan die today. :D

i have obdeleven right now and i also do a reset, TB adaption and can continue driving for a bit as well. This latest week though I have gotten the fault to come back within 30 seconds so it seems it is no longer intermittent :) I am going to play with the wiring, i looked at live data and wierdly all the sensors seem to wiggle around, though the throttle body position ones more so.

about 3 years ago cleaning the original throttle body seems to have been enough, but it was a slightly different code that i don't remember now that i got once a year or so. Something is degrading, i am hoping its the harness and i'll just order the harness bits up next.

Here is data from a quick drive, around 85000 milliseconds you can see the TB data get erratic, and i did not blip the throttle, the ecu over rode the gas pedal position it seems and moved it to zero, i wish i could see the actual gas pedal position without the ecu override.

[G-Can]

Another thing he told me it's the pedal itself causing issues. I have it hard to believe that wires alone would go bad, it's more a position sensor in the pedal, or on the TB.

Please do share a source for those if you end up getting something.