Good evening all, had an unsual experience driving home from Philadelphia to South Carolina. Having no issues for atleast 400 miles on my trip traveling at 75 mph, the cruise control disengaged without tapping the brake. Tried to engage, nothing happened. When up to speed again, the rpms would spike at times, then settle out. I was alittle nervoous the rest of the trip, dark road and shops insight if needed. Any clues to what could have caused this issue. Thanks

99 V70 T5 150k miles

Not enough data to process. When you said the rpms would spike, did you mean that you could also hear the engine increase rpms to red line, or just the gauge spiked?

Are there any messages or idiot lights on?

Is your ETM original? Has the throttle position switch been cleaned?

I assume that the check engine light is not burned out?
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My back feels better when I sit in a Volvo seat

Sorry, no CEL

I could hear the engine and see the rpm gauge spike up, The ETM has a yellow sticker so from what I've read, it has been updated. Not sure how to clean the module.

When an error is detected by the ECM, it will disengage the CC. I suspect that there is an error and if you have a scan tool try to read it. It might be 'pending', but that is not normally the case. Autoparts stores usually read the codes for free, but they are generic (Pnnnn).

The ETM is held in by a few hard to reach screws and an electrical plug. The throttle position sensor is attached to the ETM. Throttle body cleaner works wonders.
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My back feels better when I sit in a Volvo seat

Thanks Klaus as always, a life saver! Happy Holidays!