So, finally got my car going (03 ls v8). The car was sitting for a few years due to harsh shifting in the transmission. Before it sat my buddy had replaced the transmission with a new one and it still shifted hard. He bought a used PCM on eBay and fixed the issue for about 6 months then started doing it again. He never replaced the coils, and it was misfiring slightly while he drove it. My thought was that it possibly burnt up the PCM from being strained by the coils. So, I sent the PCM to SIA and when I got it back and installed car went almost instantly into failsafe and started shifting hard again. Scanned the car with forscan and got a code for cht sensor. Replaced the sensor and it stopped going into failsafe but still shifted hard. Sent the PCM back to sia (lifetime warranty). They said they got it fixed again. Tried the pcm and went straight into failsafe again but for different codes. So, I tried another used PCM I got with the car. Worked for about a mile and shifted fine but then BAM shifted rough again. My thoughts are since it is doing different things every time I put in the PCMs, I am leaning towards it being the PCM. If it was doing the same thing I would understand it being something in the transmission. Thinking about trying a PCM from Flagship1 even though they are $800. Any input would be appreciated.
PCM or Transmission
- Thread starter jc0528
- Start date
joegr
Dedicated LVC Member
I wonder if you have a problem with the solenoid pack in the transmission that is damaging the PCMs. Did SIA indicate which parts were being replaced each time they repaired the PCM?
Also, some transmission faults will can be masked until the adaptations start. You said the last PCM worked for about a mile. If you reset it (battery disconnect), will it go for a mile again?
Also, some transmission faults will can be masked until the adaptations start. You said the last PCM worked for about a mile. If you reset it (battery disconnect), will it go for a mile again?
SIA said the first time they repaired transmission circuitry. The second time they said that they repaired a loose capacitor in transmission circuitry. I did not try resetting the battery and going again on the other PCM.
04_Sport_LS
Dedicated LVC Member
The 2003 and 2004 V8 LS transmission had a known issue with the solenoid pack.
Actually... the 2003 LS transmission had a few known "quirks".
Depending on the milage, your transmission may also need a drive band adjustment.
The car has a new transmission with maybe 1000 miles on it. You would think it would be okay, but I guess not with these cars.
04_Sport_LS
Dedicated LVC Member
Have you messed with anything on the engine? Like around the throttle body. Specifically the throttle body connector.
Sometimes the pins in the socket get bent or folded over.
Sometimes the pins in the socket get bent or folded over.
Yes, had to take of intake to do head temp sensor. But ive put in a pcm three times, one of them fixed by SIA twice, and a used one I had. Each time it is doing different things (going into failsafe and not), shifting hard at different points.
04_Sport_LS
Dedicated LVC Member
That doesn't necessarily mean the drive bands were adjusted.
04_Sport_LS
Dedicated LVC Member
You might want to check the plug/socket for bent pins on the throttle body.
I understand what you are saying but before it was parked. He put in the used PCM and it did fine shifting. I just thought that the bad coils caused a pcm strain and fried it.
I will check this out, but would you not expect to get throttle body codes or not necessarily.
04_Sport_LS
Dedicated LVC Member
It's been a while (over a decade) since somebody bent the pins on the throttle body. IDK if codes popped up... or if so... what they were.
@jc0528 i had some of the same problems you have mentioned when i bought my 06LS. Mine went like this, hard rough shifting trans went out. Rebuilt the trans then maybe a week later my LS goes into ETC failsafe mode. I took my throttle body apart to find what specifically went wrong with it. On the right side of the throttle body there is a small electric motor with a round metal cylinder covering it. If you take that cylinder off and look inside of it there are magnets glued to the inside. Those magnets are supposed to hold that electric motor perfectly in the center when its turning and communicating with the PCM. My magnets had started coming unglued and was hitting that electric motor until finally one of them completely come unglued and stuck itself to the motor causing it to bind up throwing my LS into ETC Failsafe mode. I replaced just that metal cylinder with one off of a 06 Ford Explorer throttle body i had setting around and it fixed my failsafe mode and haven't had anymore problems. Makes me wonder if those magnets being loose was why my trans had started shifting hard in the first place until it finally broke. Hope this helps with your gremlins.Good Luck.