VR Auto PCM Speed Sensor Info

Ecu Hardware Modifications
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VL400
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VR Auto PCM Speed Sensor Info

Post by VL400 »

Having finally upgraded to a digi scope, so thought it was about time to start documenting a few things. Will start with speed sensor input and output for the VR auto PCM (it also applies to series 1 and 2 VS V8 PCMs). Will also show how to convert the PCM to work with a manual hall effect signal later.


The PCM uses a chip to process the reluctor input and provide various outputs....
VSS Board Layout.jpg
VSS Board Layout.jpg (487.55 KiB) Viewed 4787 times

The signal from the reluctor speed sensor (yellow trace) is clamped to ~1.4v p-p (blue trace) before the input of the VSS processing chip. I have used a sine wave for this test as it was just done on the bench...
Input to VSS Processing Chip.jpg
Input to VSS Processing Chip.jpg (36.22 KiB) Viewed 4787 times

There is a divide by 10 output that goes to pin C12. The blue trace is what gets sent to the dash...
PCM to Dash.jpg
PCM to Dash.jpg (39.25 KiB) Viewed 4787 times

The CPU uses a counter for calculating the vehicle speed. A 3uS pulse from the VSS processing chip (blue trace) occurs on every rising and falling edge of the reluctor signal....
Output to VSS Counter.jpg
Output to VSS Counter.jpg (33.87 KiB) Viewed 4787 times



Will add more info to this thread later :thumbup:
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antus
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Re: VR Auto PCM Speed Sensor Info

Post by antus »

Love your work, and documentation :thumbup:
Have you read the FAQ? For lots of information and links to significant threads see here: http://pcmhacking.net/forums/viewtopic.php?f=7&t=1396
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The1
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Re: VR Auto PCM Speed Sensor Info

Post by The1 »

nice stuff! :thumbup:
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