1995 Buick Park Avenue Speedo Drops to Zero

1995 Buick Park Avenue. Check Engine light goes Off and On. No signal from VSS dont remember the number. The BCM was changed once and the Heater Control was changed. Worked great for about three months after that. New VSS, new pigtail to VSS, ran wires to the computer from VSS, cause broken wires there are common I guess. Numerous trip to shops. Many hours of my own time.

Question: Ok here it goes, We have a 1995 park avenue and at random usually low speeds or from a stop, the speedo will drop to 0. When this happened the car only has 2nd, 3rd Gear it acts like trans is unplugged. No overdrive and check engine light it give a code of no signal from speed sensor. Called a tech line I was told to check that get a volt meter and put it on ac Volt, and I should get about 1 volt per mph.

That was wrong that is when I changed everything same readings, at 35 mph it read 50 volts. To make It work again sometime you can stop the car and turn it off and restart and quickly get out of town and run the car to 3000+ rpm and it will shift. The check engine light goes away and then all of a sudden its back to normal. Other times I just have to drive it until it starts to work. Ive spent piles of cash having every respectable shop and auto electrician give it a crack. The last place I was at told me to try change the gauge cluster. Wow what a disaster. Any help would be appreciated.

buick park avenue

Answer: With all the things you have done, and it being intermittent, i would suspect either a problem with power to the PCM, ground of the PCM, or a faulty PCM. Especially as how you turn the car off to get it to correct itself some times.

This is a straight forward circuit- VSS, 2 wires straight to the PCM. The not shifting is a result of no VSS- it is a default. Does not sound like the cluster, since the PCM tells the cluster what to do.

Loss of voltage to the trans. solenoids would cause many different codes, not normally a VSS code, since that sensor is not powered up like the shift solenoids, etc. Try tapping on the PCM to see if you can cause the speedo to act up.

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