My car had a bad brake pedal switch. Taillights stayed on for a few seconds after the pedal was released. Also had an ABS module issue. Replaced the battery, repaired the module, put in a used brake switch from a parts car. Now I have no DTCs, no ABS/DSC warning, and the light is one for the cruise to operate. Cruise is not actually working. When I push the "+" button I feel a small surge from the car but the cruise never "sets."

After driving for awhile the "Engine Failsafe Mode" message comes on and the light on the Cruise goes out. I feel like the car begins running poorly when the light comes on.

Any wisdom? Switch is not new but the brake lights work properly now and there is no code.

 

What mystery car do you have?
There are different faults with the 2 different throttle assys. (AJ26 and AJ27)

bob

 

Sorry, 2001 XJ8 4.0

Based on others experience I drove the car with cruise switch off, and now have no failsafe message. Makes me suspect the used switch.

 

I had "Engine Failsafe Mode" in my 2001 XJ8 with NO DTCs in the ECM.
I also noted an 'unsteady' engine speed during light throttle application. The engine would change RPM slightly with no input from me.

I performed a 'throttle data download' and no THROTTLE ACTIVATION RECORDED was seen in the readout.

I still suspected the throttle so I found a used throttle from a damaged 2003 XJR here on my property.
The SC throttle lacks the 'AIR ASSISTED INJECTORS' but the small parts can be swapped from the original throttle.

Swapped the throttles and NO MORE "Engine Failsafe Mode".

Just something to think about??

bob