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ECU Reset

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The Ford Mondeo hit our roads in 1993, and has consistently been a sales success. Now on it's 4th incarnation, it remains a drivers favourite.
For more information, visit the Ford Mondeo forum on, the definitive resource site covering all Fords from the present day to the 1970's.

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Courtesy of
Ford Model: Mondeo Mk1/2/3
Estimated Cost: N/A
Difficulty? Easy
How long does this take? 5 minutes


When making mods to your engine, it might be an idea to reset the ECU so that it can relearn and adapt to the changes.


The easiest way to reset the ECU is to remove fuses 4 and 11 from the fusebox next to the battery in the engine bay and leave the car for about 15 minutes. (This is the case for the Mk1 and Mk2 Zetec engines. Check your user guide for other models) Identifying the fuses means that you will not have to reset your clock or radio, which you would have to do if you were to disconnect the battery.

When the fuses are re-inserted, your car's ECU will relearn according to how you drive your car. This can take anywhere from a couple of hours to a week or so. However, the following steps might speed the overall process up:

Start the car and leave it idling for 15 minutes or so... it will probably stall a couple of times, but it'll soon level out at just under 1,000 revs

Then take the car out and drive it as carefully as you can for an hour or so

Finally, take it out onto the longest road you can find with a national speed limit and open the throttle up


The procedure for the Mk3 is slightly different, according to the Haynes manual. They recommend doing the following once the PCM (or ECU) has been disconnected for a while:

To allow the PCM to relearn, start the engine and run it as close to idle speed as possible until it reaches its normal operating temperature Then run it for approximately two minutes at 1200rpm Next, drive the vehicle as far as necessary - approximately 5 miles of varied driving conditions is usually sufficient to complete the relearning process. Don't forget to reset your one touch windows and change the clock to the correct time!

Note, this mod will also reset your stereo if you disconnect the battery to reset the ECU, so if you dont have a code for it, now is a good time to get one!