I have an LLY that won't crank. I think it may need a PCM but I wanted to get some opinions.
The problem started (I think) over the winter when I had a plow pump solenoid that shorted out randomly and would drain the battery in a few minutes. Shortly after, the truck threw a P0601 code (TCM ROM fail). The truck ran fine for about a month and I would clear the fault when I was tired of looking at the CEL. Sometimes it set again in seconds, sometimes days.
The truck wouldn't start for the first time about 3 weeks ago leaving my parents house. I put the key in the ignition and tried to start - nothing. All lights were on, accessories worked, but not a sound from the starter or starter relay. I jumped out the starter relay and she cranked, so I ruled out the starter. When trying to figure out the problem I noticed my fuel low light was on and I just filled up. I then noticed my range, oil minder, miles to empty and few others all had "---" for a reading. It was late and I my father offered me a ride home so I gave up, I just hopped back in the truck and was going to roll up the windows and decided to try it again - IT STARTED! I drove it home (~30 min) no problems. Shut it off, started it up, shut it off, started up. all good. Ran fine for about 3 weeks starting and stopping about 40 times.
Then it died at my buddies house and I got it towed back to my parents place (was closer to my buddies, and insurance only covers 15 miles). Same symptoms as above. I replaced the NBSU switch as the gears were slow to change, but it made no difference. I checked wiring from the ignition switch to the fuse block and it all seems well. I did notice the ignition relay was not energizing. I had 12V on side of the coil, but the other side coming from the PCM will never ground out.
Do I need a PCM or is it something simple? The only thing that concerns me is that P601 code as it is for the TCM and not the PCM. Will a faulty TCM prevent the truck from starting? The gear indicator is showing up properly on the display. If I do need a PCM, where is a good place to get one that's programmed? I really don't want to drag it to the dealer. Sorry for the long post, just wanted to give some detail. Thanks in advance!
The problem started (I think) over the winter when I had a plow pump solenoid that shorted out randomly and would drain the battery in a few minutes. Shortly after, the truck threw a P0601 code (TCM ROM fail). The truck ran fine for about a month and I would clear the fault when I was tired of looking at the CEL. Sometimes it set again in seconds, sometimes days.
The truck wouldn't start for the first time about 3 weeks ago leaving my parents house. I put the key in the ignition and tried to start - nothing. All lights were on, accessories worked, but not a sound from the starter or starter relay. I jumped out the starter relay and she cranked, so I ruled out the starter. When trying to figure out the problem I noticed my fuel low light was on and I just filled up. I then noticed my range, oil minder, miles to empty and few others all had "---" for a reading. It was late and I my father offered me a ride home so I gave up, I just hopped back in the truck and was going to roll up the windows and decided to try it again - IT STARTED! I drove it home (~30 min) no problems. Shut it off, started it up, shut it off, started up. all good. Ran fine for about 3 weeks starting and stopping about 40 times.
Then it died at my buddies house and I got it towed back to my parents place (was closer to my buddies, and insurance only covers 15 miles). Same symptoms as above. I replaced the NBSU switch as the gears were slow to change, but it made no difference. I checked wiring from the ignition switch to the fuse block and it all seems well. I did notice the ignition relay was not energizing. I had 12V on side of the coil, but the other side coming from the PCM will never ground out.
Do I need a PCM or is it something simple? The only thing that concerns me is that P601 code as it is for the TCM and not the PCM. Will a faulty TCM prevent the truck from starting? The gear indicator is showing up properly on the display. If I do need a PCM, where is a good place to get one that's programmed? I really don't want to drag it to the dealer. Sorry for the long post, just wanted to give some detail. Thanks in advance!
