Unstable idle : not the IAC valve

[GEN 3 SHO FAN]

Hi,

Some times ago, I was working on the brakes while it was started and I had often the idle going up and down. I knew the trouble comes when the engine is hot most of the time but not that much.

While working, the fans kicked in and at this exact moment, the idle trouble starts too... I realized that my trouble wasn't coming from a bad valve but rather from the module controlling the radiator fans (black plastic box on the side of the battery, don't recall, CCRM ?). I had another spare one from a SLO that I put, the trouble completely disapeared but my fans still going on after the car is turned off. I put the older one and the trouble returned, but less often.

It's seems that this module also controls the IAC valve. And I rode somewhere that others Ford models had troubles with this box too.

I know that many owner had this trouble, just my 2 cents.

 

[shaw]

Hi,

Some times ago, I was working on the brakes while it was started and I had often the idle going up and down. I knew the trouble comes when the engine is hot most of the time but not that much.

While working, the fans kicked in and at this exact moment, the idle trouble starts too... I realized that my trouble wasn't coming from a bad valve but rather from the module controlling the radiator fans (black plastic box on the side of the battery, don't recall, CCRM ?). I had another spare one from a SLO that I put, the trouble completely disapeared but my fans still going on after the car is turned off. I put the older one and the trouble returned, but less often.

It's seems that this module also controls the IAC valve. And I rode somewhere that others Ford models had troubles with this box too.

I know that many owner had this trouble, just my 2 cents.

That actually makes a lot of sense. The CCRM has caused all kinds of weird intermittent issues on these cars over the years, especially once heat gets involved. I remember chasing an idle problem forever on mine before finding out the fan control side of the module was acting up and causing voltage fluctuations whenever the fans kicked on. It’s crazy how one box can make the car seem like it has an IAC, cooling, or even charging issue all at once. The fans staying on afterward definitely sounds like the spare unit may have had its own problem too. These old modules are getting harder to find in truly good condition.