azrocketman

I've been chasing a somewhat intermittent Code 24, Vehicle Speed Sensor, problem on my 1986 convertible (aluminum heads, automatic) since I purchased the car in July 2009 with 73,000 miles. I swapped the ECM today thinking that this may be a contributor to the problem (after previously reseating the instrument cluster connectors and replacing the VSS on the transmission). Still no joy.

During the swap I was surprised to find a Hypertech chip assembly in the place of the stock MEM CAL. The Hypertech part number is 156342.

My questions are: Is it possible that there is some change in the Hypertech programming that can cause the ECM to throw a Code 24? What benefit does this Hypertech chip set provide?

Does anyone have a stock MEM CAL available for my car? The car is a stock L98 (to the best of my knowledge), automatic, and aluminum heads. The replaced ECM has a paper tag with the following information:

Service Number: 1227165
AANM
862251
M621796970

Thanks,

Steve

C409

I seriously doubt that your issues are related to the hypertech prom ... on L98's the hypertech uses the ARAP bin's spark maps because they're a bit more aggressive and usually changes the on / off settings for the engine cooling fan ... not much more than that ........... I would check the wiring between the VSS and the ECM ... it helps if you have the factory Helms service manual ... there are diagnostic flow charts and wiring schematics that will make the job easier .........