Fault Code 25
Description: AIS (Automatic Idle Speed) motor circuit shorted or target
idle speed not reached
Power loss light: Off
Limp-in mode: None
Vaccum leak - Check all vaccum lines for cracks or breaks.
Bad connection or wiring - Check the wiring and connections between the
logic module and the motor. Clean and regrease any corroded connectors with
dielectric grease and repair any shorts.
Shorted or frozen AIS motor - The AIS motor is located near the TPS. For
1987 or earlier Turbo I engines, remove the bolt and slide the motor out
(you may have to wiggle and twist it). Remove the clamp and carefully pull
out the motor. Be sure and observe how it goes together, especially the
orienation of the rotatiing valve inside. Hook the motor to a 12V supply to
see if it runs. If it doesn't, replace the AIS. Clean all the gears and
shafts throughly and reassemble the gear and valve assembly. Spray all the
gears and parts with TriFlo or a similar silicone spray lubricant (don't use
WD40 because it evaporates) and insert the motor. If the engine seems to
race wildly after assembly (give it some time to get control), you probably
installed the internal, rotating valve backwards.
- Near 0V or near 12V not detected when the motor driver is turned on or
- Target idle speed not reached after a number of attempts
Results If Component Fails
Fault code 33 is stored.
The logic module cannot detect an open circuit in the wiring, so a fault
code may not be stored on vehicles (unknown which) with logic modules that
don't keep track of how many times it has tried to adjust the idle.