96 Corvette - Random Speedo Not working
Thread Starter
7th Gear
Joined: Aug 2018
Posts: 7
Likes: 2
96 Corvette - Random Speedo Not working
I’m working through a problem with 1996 C4 Convertible Lt4 6 Spd. where I lose my speedo randomly when driving. Here is what I know/have done:
1. I replaced the VSS twice. No change to the issue. (I am surprised that there is no retainer holding the plastic gear in place on the VSS but I assume it can’t go anywhere once in place.)
2. When I lose the speedo read out, I also lose the read out you get though the Climate Control system and the radio won’t auto adjust volume. So, I assume that I’m getting nothing out of the PCM, Blk Connector, Pin 8.
3. I have checked continuity to on the wiring from the VSS connector to the PCM, Red Connector Pin 31 & 32 and everything is good. No amount of the moving the harness effects the connection.
I’m starting to feel like it might be a PCM issue but I’d like to know for sure before sourcing a replacement. Is it possible to monitor Blk Connector, Pin 8 with a DVM? If so, what readings should I be looking for? Same as the VSS (0.5 Volts to 100 Volts AC)? Measured to GND?
Any insight or other places to check would be appreciated. This problem has really been a pain to try and resolve....
Dan
1. I replaced the VSS twice. No change to the issue. (I am surprised that there is no retainer holding the plastic gear in place on the VSS but I assume it can’t go anywhere once in place.)
2. When I lose the speedo read out, I also lose the read out you get though the Climate Control system and the radio won’t auto adjust volume. So, I assume that I’m getting nothing out of the PCM, Blk Connector, Pin 8.
3. I have checked continuity to on the wiring from the VSS connector to the PCM, Red Connector Pin 31 & 32 and everything is good. No amount of the moving the harness effects the connection.
I’m starting to feel like it might be a PCM issue but I’d like to know for sure before sourcing a replacement. Is it possible to monitor Blk Connector, Pin 8 with a DVM? If so, what readings should I be looking for? Same as the VSS (0.5 Volts to 100 Volts AC)? Measured to GND?
Any insight or other places to check would be appreciated. This problem has really been a pain to try and resolve....
Dan
Thread Starter
7th Gear
Joined: Aug 2018
Posts: 7
Likes: 2
Just an update. It turns out the VSS Connector wasn't making a good connection with the sensor. Ended up having to replace the senor a third time to resolve the issue. I assume the aftermarket sensor I installed was manufactured incorrectly.
I recommend monitoring pins 31-32 on the red PCM connector to check for OHMS when parked. Should be around 400. If you get nothing than it could be a connection problem.
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z28redline
I recommend monitoring pins 31-32 on the red PCM connector to check for OHMS when parked. Should be around 400. If you get nothing than it could be a connection problem.
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z28redline
