TPS code(bad DME?)

[plain325]

I am having an issue with a TPS code on my s52 swap(OBDII).
This is the code i am getting:
P0121 - Throttle Position Sensor/Switch A Circuit Range/Performance Problem

I replaced the TPS with a new one, checked the wiring and connections all the way back to the DME circut board.
The car seems to drive the same if the tps is plugged in or not.
Is it feasible the DME unit suddenly crapped out? Could it be the tune somehow(TRM)?
It drove fine for a while, but i started to have this issue a little bit ago.

[DesertBMW]

people have problems with TPS sensor code when using bigger bore throttle body.
Sensor is calibrated in the software for stock throttle body size. Good diagnostic scanner can read voltage from TPS in live data.

[plain325]

Stock sized throttle body, I'm going to have to find someone to help me with a scanner

[KoKoSe7eN]

Any aftermarket intake installed? Check engine light?

[plain325]

I got in the mail today a OBDii to bluetooth module. It can display live data on my phone and clear faults, its pretty neat. Anyway, its is showing that the DME is getting a signal from the TPS, the throttle position moves on my screen when i press the pedal.
Although the TPS doesnt go any lower than 15%. (my truck doesnt go any lower than 20%, so this might be normal behavior).

The thing is though, i can clear the faults, and without starting the car, the code will come back as pending.

I dont have the check engine light hooked up, though i would think it would be illuminated if i did.

[nando]

I'm pretty sure it should go down to 0%.

[nando]

people have problems with TPS sensor code when using bigger bore throttle body.
Sensor is calibrated in the software for stock throttle body size. Good diagnostic scanner can read voltage from TPS in live data.

huh? the diameter of the TB has ZERO do to with TPS calibration.

the TPS is auto-calibrated to 0% when you turn on the ignition. the only thing that matters is the angle of rotation of the throttle plate - the diameter makes absolutely no difference.

yet more nonsense from you..

[plain325]

Well the ohms seem to match what the should( according to the bentley). So, maybe the dme isnt auto-calibrating?

[plain325]

I feel dumb for not thinking of this earlier, but i am running an m50 manifold and throttle body, that means no ACS+T, would that set off a TPS code?

[caesar101]

I have the same problem, TPS code and it comes and goes. Right now the check engine light is out, but it has done this before it will be back. Live data shows changing voltage.
Don't really know where to look.

[328ijunkie]

OBD1 and OBD2 TPS are interchangable thus the TBs are interchangable.

I have had issues with BBTBs freaking TPS's out to no avail.
I usually see <10% TPS signal when its closed.

[RobertK]

Had this problem with a friend's swap, swapping the TPS didn't fix it.

Turned out that the little screw on the throttle body that sets the rest point for the throttle linkage had worked its way loose and crept forward so the rest point allowed the throttle to barely stay open just a tad.

We backed the screw out a little until it was at the correct rest point and used red loctite to keep it in place.

[plain325]

I ended up getting another DME, the code doesnt come up with the new one. I am wodering if the DME adapts to a certain tps, and if something changes, such as the signal when closed, it will throw a code.

[plain325]

Does anyone know if a drive cycle is necessary to clear some codes? I am having an issue with another code now for the vanos solinoid. As soon as i clear it, it pops right back up.
My VSS is not wired correctly, i thought i had, but during all of my investigating the other code i found i am not getting any signal to the DME for VSS.

[DesertBMW]

Does anyone know if a drive cycle is necessary to clear some codes? I am having an issue with another code now for the vanos solinoid. As soon as i clear it, it pops right back up.
My VSS is not wired correctly, i thought i had, but during all of my investigating the other code i found i am not getting any signal to the DME for VSS.

check the vanos solenoid with ohm meter, report back with reading.

I have had issues with BBTBs freaking TPS's out to no avail.

Yes, on MS41 lots of people having problems with TPS with bigger throttle body. MS41 monitors the air flow via AMM then checks against TPS, bigger TB will mess this flow calibration up and will cause DME to think TPS is showing less angle but I see more flow.