BMC330

Got new PCM in today. Cleaned ground and installed the new PCM. I still have no change in the truck. No power above about 1/8 peddle. I do not have the scanner to plug into the truck at this time, it belongs to my nephew and he has to use at his shop during the week. It will be this weekend before I can get it back. I have new codes with the new PCM by key display. P0122 P1698 P0522 P0123 P1295 Still chasing the problem. Completed APPS voltage to high test. At the end I got to replace ECM. I was allowed to borrow an ECM from a truck very close to mine. Only thing I could find was 2WD where mine is 4WD. The other ECM did not change anything on my performance. I purchased a Load Pro. I am about to start load testing ground wires. Maybe I will find the problem today.

Got new PCM in today. Cleaned ground and installed the new PCM. I still have no change in the truck. No power above about 1/8 peddle. I do not have the scanner to plug into the truck at this time, it belongs to my nephew and he has to use at his shop during the week. It will be this weekend before I can get it back. I have new codes with the new PCM by key display. P0122 P1698 P0522 P0123 P1295 Still chasing the problem.

It is a 6 speed truck not auto. Im at the point i will replace both if needed. I will call them back and specify i have a 6 speed truck. Thanks for the reply.

I called auto computer spectlist. They said the PCM had no bearing on the APPS voltage being erratic. It was the ECU that controlled the APPS. Im confused as to is the issue in the PCM or the ECM. I know PCM has something to do with the APPS due to unpluging the PCM corrects my erratic APPS. Which should i be looking to replace PCM or ECU?

I have learned a lesson on this adventure. Mechanical problems are much more enjoyable to work on. Wiring issues are really a pain. I have used a Fluke Meter more in the past two days than in my entire life.

Ok. Im not sure if it has all the options as my truck as mine is loaded and the other is a work truck. I will order a new one and go from there. Thank you.

PCM is what we are thinking also. I have a friend who has a truck we may be able to borrow a PCM from to see if our symptoms go away. If he will allow us we are also going to get the ECM. I will advise when we have the PCM changed.

We unplugged the first wire bundle closest to the drivers side and apps is smooth. The graph looks perfect between apps percent and apps voltage. And we are getting 100 percent on apps. Not sure where to go from here.

PCM abnormal is all i am getting. Graph of apps sensor percent. Wide open is 65%

PCM abnormal is all i am getting.

No codes. I am scanning again now. I will advise asap IMG_0561.3gp

On the live data we found the TPS all over the chart. Looked like watching a heart monitor when I put it on the graph mode. Replaced the TPS and we are getting the same results. The TPS will read constant when only about 1/8 of the way depressing peddle. The truck seems to run fine at that point. If you mash the peddle any further the readings go all over the chart. I am only getting one code and it is a PCM fault/3. I have checked the grounds and found no issues. I also unplugged the wiring going to the ECM to check for corrosion but it looked new.

Alternator noise is .025 vac on fluke meter. Going to OHM the throttle position sensor now.

Ok, pulled the alternator and had tested at the local Autozone. Test was good. Going to borrow Fluke multi meter to check AC noise again. If AC noise checks ok will move on to the ECM and VP grounds. Thanks for all the advice. Will advise if i find my issue. One thing i noticed yesterday is throttal response is good until about a quarter of the way when accelarating. After that the truck pretty much will go flat until it reaches around 2000 rpm and the boost starts raising up. Also i noticed the oil pressure guage moves to around 40 psi when the key is on. Not sure if this matters just something I seen yesterday.

I hooked the truck up to a Matco Scan Tool this afternoon and drove it around 50 miles. I had it on the live scan mode while driving. The voltage to the ECM would go between 12 volts to 9.88 back and forth. When the truck was at its lowest power point I was only showing 9.88 volts. Could this be a ground issue? The MAP was pretty much all over the chart also. My boost gauge would show 10 psi and the scanner would go between 0 to 10 back and forth. I also had 6 pounds of boost showing with the truck not running. Im going to pull the alternator off in the morning and have it tested. Are there any more things I can check in live scan mode that may help narrow my problems?