Resetting DME to learn mode?

[wdonovan]

'02 C4 Cab. Is there a way to reset the DME (that's the ecu, engine management computer.... right?) back to learn mode? I want to force the computer to go back to neutral A/F mixtures and timing, reduce knock-based spark retard, etc. I searched and found the mention of disconnecting neg. battery cable. This would reset everything in the car, right? Including disabling the radio? I bought the car used and have apprehensions about having been supplied the correct radio code. Anyway, is there a diagnostic terminal that gets grounded to force learn mode or a reset through Durametric? Seems kind of Fred Flintstone to have to remove the battery to reset an ecu.

[1999Porsche911]

'02 C4 Cab. Is there a way to reset the DME (that's the ecu, engine management computer.... right?) back to learn mode? I want to force the computer to go back to neutral A/F mixtures and timing, reduce knock-based spark retard, etc. I searched and found the mention of disconnecting neg. battery cable. This would reset everything in the car, right? Including disabling the radio? I bought the car used and have apprehensions about having been supplied the correct radio code. Anyway, is there a diagnostic terminal that gets grounded to force learn mode or a reset through Durametric? Seems kind of Fred Flintstone to have to remove the battery to reset an ecu.

Your ECU never leaves learning mode. It adjusts for most changes immediately and a few take a couple of drive cycles. If you want to clear out any potential errors in the computer and your fuel trim, etc, simply disconnect the ground on the battery for a few monutes and you are good to go.

Edited May 23, 2007 by 1999Porsche911

[tholyoak]

According to the 7.8 DME manual:

In the event of an open circuit in the voltage supply 'terminal 30', the

following values are deleted from the control module:

All fault memory entries

Stored freeze frames of the faults (for environmental conditions,

see the next chapter)

All adaptation values

The learned values of the throttle adjustment unit

Ready statuses of individual diagnosis routines (see next chapter)

Please note that programming the DME control module (e.g. reading

in a new data record) also deletes the values referred to above.

The DME control module must perform a learning and adaptation

routine for the throttle adjustment unit if:

The power supply to the DME control module is interrupted

The DME control module plugs are disconnected

A new DME control module is installed

The throttle adjustment unit is replaced

The DME is programmed.

To do this:

1. Switch the ignition on for 1 minute without starting the engine.

Do not actuate the accelerator pedal (for instance, make sure

that there is not a carpet pressing on the pedal).

2. Switch off ignition for at least 10 seconds.

The following conditions must also be observed, otherwise learning

is not possible:

Vehicle is stationary

Battery positive voltage between 10 V and 16 V

Engine temperature between 5 °C and 100 °C

Intake air temperature between 10 °C and 100 °C

Todd

Edited May 24, 2007 by tholyoak

[wdonovan]

Thanks. I believe the ecu is behind the right rear jumper seat in my 02 C4 Cab. I will try disconnecting it to reset the computer without killing the radio and other things.