Clipped

Wondering if anyone can answer a question regarding TPS issues that have been haunting my car since I've become the unlucky owner...... It's become a pretty expensive question.

How can the TPS % be dead on from close to 99% while TPS voltage is 0 with car off - running can be anywhere from 0 to 5 volts - bounces all over the place!?!?!!

I don't understand how one can be dead on while the other is completely screwed?!??

LilJayV10

iTrader: (39)

I'm slightly confused on what exactly you are asking.

How about you give some more details...like what vehicle are you working on.

Clipped

2000 Firebird Formula. Factory PCM. HP Tune.

I can monitor throttle position % with a scan tool - engine on or off it's accurate - 0-99%. My TPS voltage is 0 at KOEO. Running the voltage is all over the place. I can't get TPS voltage on scan tool KOEO - Short the signal circuit to the 5v vref OR to battery voltage results in the same zero - should be a bad signal wire. I'm not understanding - IF that wire is bad how can throttle % still be dead on???

Results are the same with the cruise module plugged in or unplugged.

LilJayV10

iTrader: (39)

Where are you checking the TPS voltage at?

I'd also stop dumping battery voltage into a 5v system, you can let some smoke out that way.

Clipped

Thank you for the replies - I appreciate the interest!

Using scan tool pid for TPS voltage. The 5V ref was verified with a fluke at the sensor. Ground circuit load tested with a bulb at sensor.

As far as the 12V into a 5v circuit it's step 7 in service info when chasing Po122. For what its worth they want you using a test light to do it - although they don't specify what kind.....

Since its after the step of shorting Vref I'd guess they're assuming the circuit is either open or high resistance - so justifiable to use more volts? Regardless just following the book......

LilJayV10

iTrader: (39)

Have you checked the signal circuit with a meter or just the 5v?

Clipped

I have not got anything done yet with the signal circuit yet. Spent most of the day yesterday tracking down the stupid modules associated with the cruise control and isolating them. Was haunted last night with trying to figure out how the hell the % is dead on so figured I'd ask here.... Went home assuming the signal circuit to be the issue but that takes me right back to how the hell the % is right. I mean even when I shorted the 5v to signal the % jumped to 99. Not understanding how IF this circuit is open - maybe hanging on by a single strand?!??! lol.

When searching seems like the fluctuating tps voltage has happened to others but none of these shituations have confirmed fixes......