How do you do a drive cycle on a 1998 Ford Expedition?

Answer 1

The EEC-V is a powerful system that monitors the engine constantly and adjusts the mixture and timing up to 7 times per second based upon the sensor values that it reads.

Whenever work has been done on the Engine or Sensors the EEC will take time to relearn it's optimum values. This process can be speeded up by following the recommended Drive Cycle - a process designed to help the EEC-V relearn all of the sensor values. Obviously it will do so without the full Drive Cycle - it just takes longer.

The recommended OBD II drive cycle begins with a cold start (with coolant temperature below 122 degrees F and the coolant and air temperature sensors within 11 degrees of one another).

NOTE: The ignition key must not be on prior to the cold start otherwise the heated oxygen sensor diagnostic may not run.As soon as the engine starts, idle the engine in D for two and a half minutes with the A/C and front and rear window defrost on.

OBDII checks oxygen sensor heater circuits, air pump and EVAP purge.Turn the A/C and front/rear defrost off, and accelerate to 55 mph at half throttle.

OBDII checks for ignition misfire, fuel trim and canister purge.Hold at a steady state speed of 55 mph for three minutes.

OBDII monitors EGR, air pump, O2 sensors and canister purge.Decelerate (coast down) to 20 mph without braking.

OBDII checks EGR and purge functions.Accelerate back to 55 to 60 mph at ¾ throttle.

OBDII checks misfire, fuel trim and purge again.Hold at a steady speed of 55 to 60 mph for five minutes.

OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions.Decelerate (coast down) to a stop without braking.

OBDII makes a final check of EGR and canister purge.