Tech Tip: Restore Driveability and Performance after Power Disconnect – UnderhoodService

Tech Tip: Restore Driveability and Performance after Power Disconnect

Many computer-controlled vehicles memorize and store operation patterns that are lost when battery power is disconnected. The computer will use default data until a number of drive cycles have been memorized. To correct this problem the computer must go through a relearn procedure after the battery is disconnected. For the specific relearn procedures, refer to OE service bulletins or a repair manual for your vehicle. If a specific relearn procedure is not available, the following procedure can be used.

Application:
Computer-controlled vehicles.

Problem:
Poor driveability and performance after replacement of electronic control computer (i.e. hard start, stumble, stalling, etc.).

Cause:
Many computer-controlled vehicles memorize and store operation patterns that are lost when battery power is disconnected. The computer will use default data until a number of drive cycles have been memorized.

Solution:
The computer must go through a relearn procedure after the battery is disconnected. For the specific relearn procedures, refer to OE service bulletins or a repair manual for your vehicle. If a specific relearn procedure is not available, the following procedure can be used:
1. Firmly apply the parking brake and block the drive wheels to prevent possible movement of vehicle.
2. Start and run the engine in neutral to normal operating temperature or until the cooling fan cycles.
3. Automatic transmission: Allow the engine to idle in neutral for at least one minute, then in drive for at least one minute. Manual transmission: Allow the engine to idle in neutral for at least one minute.
4. Road-test the vehicle at various speeds in excess of 35 mph.

Caution: Always disconnect the negative battery cable before using any electric welding equipment. Failure to do so may damage the computer and void the warranty.

Tech Tip courtesy of CARDONE.

For additional information on products offered by CARDONE, visit www.cardone.com.

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