__ GM code gurus please enter __

[Blain]

I've got a 92 S10 that idles very fast and doesn't slow down. The engine is a 4.3L V6.

The engine codes I get are as follows...
22 - * "Throttle Position Sensor (TPS) - signal voltage is low during engine idle" * "Fuel cutoff relay circuit - open or shorted to ground"
&
35 - * "Idle Air Control (IAC) system problem - can not set desired RPM"


My question is... Would a bad TPS be the root cause of 22 AND 35?

 

[Analog]

Originally posted by: Blain
I've got a 92 S10 that idles very fast and doesn't slow down. The engine is a 4.3L V6.

The engine codes I get are as follows...
22 - * "Throttle Position Sensor (TPS) - signal voltage is low during engine idle" * "Fuel cutoff relay circuit - open or shorted to ground"
&
35 - * "Idle Air Control (IAC) system problem - can not set desired RPM"


My question is... Would a bad TPS be the root cause of 22 AND 35?

i'd start with the IAC. TPS may get bad data if the IAC is not working properly. My Fiero's '88 2.8 had an IAC problem that resulted in multiple faults.

 

[SuperSix]

Originally posted by: Blain
I've got a 92 S10 that idles very fast and doesn't slow down. The engine is a 4.3L V6.

The engine codes I get are as follows...
22 - * "Throttle Position Sensor (TPS) - signal voltage is low during engine idle" * "Fuel cutoff relay circuit - open or shorted to ground"
&
35 - * "Idle Air Control (IAC) system problem - can not set desired RPM"


My question is... Would a bad TPS be the root cause of 22 AND 35?

Doubtful. You can check the TPS with a digital multimeter, (If you know the acceptable ranges), and the IAC may be clogged up w/soot/carbon, I would pull it out, clean it GENTLY, and put it back in. there's an IAC reset procedure too. THe IAC is basically a plunger on a screw motor that adjusts the amount of air bleed into the intake to maintain IDLE RPMs.


Here's a Buick Turbo Regal reset info page,
and Here's a TPS adjutment FAQ for the Buicks as well. Obviously, these are for ROUGH reference only, and you should find specific procedures for your vehicle. The functionality is the same. YMMV, and if you break it, it's not my fault. 😀

 

[Blain]

Rock On! 😀

I replaced the IAC valve first, didn't help. I then replaced the TPS and BINGO... that did the trick!
I didn't get hurt too bad. $19 for the TPS, $25 for the IAC valve and $7 for a torx bit set. 😉 While I was at the O-So-Crowded Walmart, I also picked up a pair of Rhino Ramps.
No, that's not my Pantera. 😉