Engine/Transmission (1998.5 - 2002) random power loss98 1/2 24 valve

[DMSmith]

i have a 98 1/2 24 valve, auto trans,115k miles. have lost power,rpm drops to idle, acc pedal has little to no effect. power regains after 30 to 60 seconds. occurance is randon and increasing in frequency. using scan guage II,below codes are set and check engine light comes on. Not all codes are set each time. 0121 apps signal voltage too low. 0122 tps/apps signal voltage too low. 0622generator field not switching properly. 1693 companion dtc s -fault in ecm/pcm. 0000?? Al suggested mods have been done relating to torque converter lock/unlock in apps circuitry. Andy Redmonds filter kit finally cured that problem. have removed battery negatives overnite 3 times. DMSmith Chama NM.

 

[JLandry]

DMSmith,



The P0121 and P0122 are related. With the symptoms you've describe, in order of probability my guess would be the (APPS) Accelerator Pedal Position Sensor is failing, or there's a wiring problem in the APPS circuit, or there's a problem with the ECM. The easiest and fastest thing to do is to install a new sensor for the APPS and see if that cures the problem. You can buy one from Geno's Garage here. Beyond that you'll have to troubleshoot the wiring harness and the steps are a bit more than I have time to post at the moment. Let me know if you get to that point.



As for the P0622 trouble code, that's set when the PCM tries to regulate voltage output from the alternator but it doesn't happen as expected. In order of probability it could be caused by a bad alternator, wiring harness problems, or a malfunctioning PCM. If you're not experiencing any battery charging or system voltage problems, I'd first start by clearing the code and see how soon it comes back (if at all). If it does return, then I'd replace the alternator with a new one and see if that fixes it. If not, then like the APPS problem you're looking at doing some wiring harness verification tests. You can buy a brand new alternator on eBay for about $100 here. I have one on my truck and works perfectly.



Please let us know how things work out.



Good luck,



John L.