Hey guys I have a 1999 Chevy blazer that's been giving me trouble. I drove my vehicle to town that's a half hour away then a code came up. P0122. Now when I got it home I bought a new tps and put it on. But I cleaned the throttle body, iac, egr and all that beforehand. Now when I put everything back together the code came back fast and now it runs rich and idles real bad in reverse. The voltage is still low on the tps circuit. What do I do now? It's throwing me off cuz it never ran rich before and it even backfires now. It's only one code still, p0122.

 

i will assume you used a code reader to clear the code? I always found clearing it by the battery method didn't always work.. the p0122 code definition is TPS/PEDAL POSITION SENSOR A CIRCUIT LOW IMPUT could be it is not seated tight or correct, you may also want to check the wires and connector,

 

Yeah I guess I got to see if there's a short somewhere from the connector to the pcm. I cleared the code via code reader but it came back anyway. I did it that way and by disconnecting the battery. If I can't find a short I feel like it's gonna be a needle in a haystack kind of thing

 

How can I tell if the connector to the tps is bad? If there's low voltage could that be a sign it could be bad?

 

Follow the flow chart in this link, and it will take you right to the problem: https://blazerforum.com/forum/diagno...plained-35161/

 

Sorry I've been busy. Thanks though I'm gonna get on this tomorrow and see what I can figure out.

 

So when I run a separate wire from the tps to the connector to the computer. Now it's at 1.4 volts, instead of .5. Then at wide open throttle it only goes to 1.8. It's supposed to be at 4.5 to 5 volts. What am I missing here? You think it can be a bad computer?

 

Are you sure you installed the TPS correctly? The "tab" on the throttle shaft must engage the TPS sensor correctly. If it's not engaged properly, the dark blue wire will not indicate reference voltage at WOT, (wide open throttle). I would seriously doubt that the PCM failed, extremely rare.

With the sensor unplugged, ignition in the run position, the grey wire should show close to 5 volts DC. The black wire should show less than 5 ohms resistance to ground.

 

How should it be installed then?

 

Found the problem.....found a short in the wire and repaired it. The old tps was shot too. So I found my problem! Now there's a p0300 code so I'm gonna do some searching on this forum and just do a process of elimination kind of thing. Soon it'll be all good to go off reading again!