tranzam98

121 122 have those codes that keep showing up. I replaced the tp sensor and it still gets those codes. The car shifts into OD way to soon and wont down shift out of OD sometimes. Anyone ever have this problem or know what to look for to fix it?

Catskynr

P0121 sets when the predicted throttle angle does not match the actual throttle angle.
P0122 sets when the TP sensor signal voltage is less than 0.2 volts.

It sounds like you have a wiring problem ( broken wire somewhere). You can count on this low voltage being lower than normal closed throttle voltage. A bad ground would increase sensor output so rule that out. It is possible that your 5 volt reference voltage took a dive so carefully inspect the wiring to the sensor. To save weight, the wiring is smaller and is more prone to breaking inside the insulation. The telltale signs of internal breakage would be a bubble in the wiring insulation. You could also have had a loss of 5 volt reference from the PCM. If so, you would expect DTCs from other sensors using the same 5 volt reference. Usually this is an EGR DTC.

Black LS1 T/A

Looks like we posted almost the same time:

HELP! Short-Shifting out the hole - any ideas?
https://ls1tech.com/threads/showflat...31&fpart=1

tranzam98

okay a break in the wire i can fix. I think it may be more than one wire thats broken cause sometimes it shifts hard as hell when i put it in drive. so that would be the ground. any one know what pin # the 3 wires go back to. i will run a new line

abarus

Did the rewiring fix your problem?


The P0121 error is killing me. Does anyone know how to set the throttle angle back to 0%? or how to fix this error.

Thanks in advance!

tranzam98

i re-wired all 3 wires back to pcm and still not working right. when it shifts to soon i can put it to the floor and it wont down shift and autotap shows 100% for TP. Dont know if its the tranny or the pcm that messed up but i know its not the tps or wires going to it cause autotap shows it working fine.

abarus

I am having the exact same problem. I am hoping it is due to me moving the tb screw. I am going to check tonight with a voltmeter to see if the setting at closed is 0.6v and at full throttle is 4.65v. I will let you know if that fixes it.

abarus

Well, I checked my settings and at closed throttle it was at .8 and WOT it was at 4.35. I have adjusted the screw so that it is now reading .62 and WOT is still 4.35, but autotap shows that as 100% throttle. I have reset the pcm and the DTC has not shown back up yet.

FrankSS

iTrader: (18)

i got that code when i reprogrammed my car also. i am also having the same tranny problems you are too. if yall find a fix let me know too...

abarus

I have been driving my car for several days and no dtc. The tranny is shifting fine now and everything is working.

Bink

Abarus -exactly what and how did you check your sensor?? TIA.
jol(Bink)

tranzam98

i put in an ecm from some one elses car an it ran fine so im going with i have a messed up computer in my car.

abarus

Here's what I did exactly

Bought a multimeter, set it to the 0-20vdc setting. Next turned my ignition to the on position. Punctured the blue wire going to the TPS with a sewing needle. Placed the positive lead from the multimeter on the sewing needle and the negative lead on the bolt for the strut tower brace. The reading was 0.8v Next I turned the idle screw down until it was at 0.62. Then I opened the throttle body all the way and it read 4.35. I had it autotaped from a friend later in the week and it showed that it was at 0% throttle closed (0.62v according to multimeter) and 100% (4.35v).

I hope this fixes it for you