Got a new code scanner to address my blown #28 Fuse. After replacing the fuse my Envoy runs again but I don't trust it because it just blows the fuse randomly. I thought I figured it out a few years ago by replacing all the coils and it ran fine until 4 days ago. So, my new code scanner doesn't see the PCM. I tested the new scanner on my other car and it works no problem. Would this indicate a bad PCM? Thanks for any input. c good
New Code scanner won't link to PCM.
- Thread starter c good
- Start date
What was the second car you tested the new scanner on?
What year is your Envoy? Doesn't show in your about info.
Hi TJ, Envoy is 2002. Other car is 1997 Toyota Corolla. Works on the Corolla. I just checked the Cigar lighter fuse number 13 as it supplies power to the obd port. It tests fine. I'm going to have to start pulling sensor plugs one at a time and see if that helps me find the problem. If they all test out good I'm probably looking at a new PCM....ugghhhh.....
2002 will most definitely be J1850 VPW. The Toyota I have no idea. If it uses J1850 VPW it will have connections in pin 2,4,5 and 16 of the DLC port.
I wouldn't look at PCMs until a lot of checks prove an issue.
If it runs then it communicates. There is no running without communications.
A multimeter set to a low DC volts setting, something that will show 2 to 5 volts or so could be used to check for a fluctuating voltage between OBD2 pin 2 which is the data line and ground. With the key in RUN there should be a low rapidly changing voltage. If nothing then your DLC terminal 2 (purple) wire isn't connected to the SP205 splice pack!
Could stop by an auto parts and see if they can scan it. If their scanner connects then you know it's your scanner.
I wouldn't look at PCMs until a lot of checks prove an issue.
If it runs then it communicates. There is no running without communications.
A multimeter set to a low DC volts setting, something that will show 2 to 5 volts or so could be used to check for a fluctuating voltage between OBD2 pin 2 which is the data line and ground. With the key in RUN there should be a low rapidly changing voltage. If nothing then your DLC terminal 2 (purple) wire isn't connected to the SP205 splice pack!
Could stop by an auto parts and see if they can scan it. If their scanner connects then you know it's your scanner.
gmcman
Member
- Dec 12, 2011
- 4,656
This is where I would start... See if its a code scanner issue, or a port issue. Also be sure the scanner supports the J1850