I posted this in the Electrical section but got no reply so I am truing here.
My cruise control only works intermittently. I read a thread somewhere on this site that it could be caused by bad PMD (of which I have) I wasn't sure if this was sarcasm or fact. Could someone clear this up for me?

Thanx
Joe

It's fact, Joe. Whenever your PCM reads a 'soft' code situation - where there are a certain number of failure events in the ign cycle for every 1000 revolutions (can't remember how many) it calls an alert. What happens is, you lose some advance on your timing, you lose cruise, and it limits the amount of fuel / boost you can get... sort of a protective measure.

And there are a couple different levels of this... in the worst one, your SES light stays on, the engine has no power and makes crazy noises, in the lesser, the light never comes on but you lose cruise and some advance and fuel.

In both cases, shutting off and re-starting will reset your PCM and life is good again. When your PMD is failing, it can set these trouble codes, cause you the grief, and there will be no record in your code history that anything ever happened - one of the reasons GM techs can't find out what went wrong and end up charging you $50 to say 'well, it's fine now'.

When my PMD was failing, I literally had to pop it into neutral, shut it off, start it up, and then back to drive... in freeway traffic with a 5th wheel on my back. Not cool at all.

Clear as mud?
Jim

It's fact, Joe. Whenever your PCM reads a 'soft' code situation - where there are a certain number of failure events in the ign cycle for every 1000 revolutions (can't remember how many) it calls an alert. What happens is, you lose some advance on your timing, you lose cruise, and it limits the amount of fuel / boost you can get... sort of a protective measure.

And there are a couple different levels of this... in the worst one, your SES light stays on, the engine has no power and makes crazy noises, in the lesser, the light never comes on but you lose cruise and some advance and fuel.

In both cases, shutting off and re-starting will reset your PCM and life is good again. When your PMD is failing, it can set these trouble codes, cause you the grief, and there will be no record in your code history that anything ever happened - one of the reasons GM techs can't find out what went wrong and end up charging you $50 to say 'well, it's fine now'.

When my PMD was failing, I literally had to pop it into neutral, shut it off, start it up, and then back to drive... in freeway traffic with a 5th wheel on my back. Not cool at all.

Clear as mud?
Jim

You have NO idea as to how much I appreciate your answer. I will pick up my new PMD is saskatoon tomorrow or tues & remote mount it.

Thanx again
Joe

As always, JI's words are those of wisdom. I had intermittant cruise control problems until I remoted the PMD into a FSD. No cruise issues since!