e450 cruise control problems

carringb wrote:
2006 is PCM controlled, and simply uses the electric throttle body for speed control. You likely have some stiction in the throttle body, which should trigger the check engine light. It would definitely be useful to pull the codes, in case it’s just a dirty MAF. Although it’s all part of the same assembly. They are not a lifetime item. It’s very common to need to new electronic throttle body after around the 10-year mark.

Thank you for all the info. will check with ford tech when I return to green bay.

2006 is PCM controlled, and simply uses the electric throttle body for speed control. You likely have some stiction in the throttle body, which should trigger the check engine light. It would definitely be useful to pull the codes, in case it’s just a dirty MAF. Although it’s all part of the same assembly. They are not a lifetime item. It’s very common to need to new electronic throttle body after around the 10-year mark.

carringb wrote:
There is no Cruise Control Module on the E-series. It's either vacuum-controlled (pre-2005) or PCM controller (2005+, when the TorqueShift came out).

A loss of cruise control combined with a check engine light on a vacuum-servo system would make me suspect a large vacuum leak. It could be the servo itself, but could also be a stuck evap solenoid, or possible even the vacuum hose coming off the intake manifold. Are you able to get air to blow out the dash-vents?

Yes. Am able to get air thru the dash vents. My unit is a 2006 with a 6.8 liter engine. This problem has occurred at least 3 times over past 4yrs. Could this indicate a servo or stuck evap solenoid? After each occurrence, I've shut motor off. Then started use again with no problem for almost a year or more.

theoldwizard1 wrote:

carringb wrote:
There is no Cruise Control Module on the E-series.

Depends on age ! My '98 has a separate module.

Interesting. I wasn't aware of that. Mine does not. The CC is vacuum servo operated with a vacuum solenoid PWM controlled by the PCM.

carringb wrote:
There is no Cruise Control Module on the E-series.

Depends on age ! My '98 has a separate module.

There is no Cruise Control Module on the E-series. It's either vacuum-controlled (pre-2005) or PCM controller (2005+, when the TorqueShift came out).

A loss of cruise control combined with a check engine light on a vacuum-servo system would make me suspect a large vacuum leak. It could be the servo itself, but could also be a stuck evap solenoid, or possible even the vacuum hose coming off the intake manifold. Are you able to get air to blow out the dash-vents?

I'd start by getting or borrowing a code reader and seeing what codes were recorded in the ECU when the engine light went on. Maybe it's cruise control related, maybe it's just coincidence and nothing more that the cruise control was on.

One fairly common cause of cruise control problems on these Fords is the brake pressure switch that disengages the cruise control; the seals in the switch can wear out over time and brake fluid work its way in and cause problems with the switch contacts. I think the usual result is the cruise control just doesn't work, but not the engine light coming on. (It can also lead to fires, even when the vehicle is parked and turned off; there was a wide-ranging recall to prevent that from happening.)

What engine ? What model year ?