Hi on scanning my skoda fabia 1.2htp 2007 I get errors of under voltage for various things such as ABS, AIR BAG cannot connect to radio and comfort module.

The battery is new and voltage when turned on acc is a steady 12.6 with 14v with engine running.

The earths are good so I am thinking of disconnecting the battery shorting neg to pos then disconnecting the ecu and spraying the connections with contact cleaner.

I know to set the heater to cold and my car does not have remote central locking.

My question is, if I disconnect the ECU will it retain vital stuff like the immobiliser codes or is there anything it may not retain that will affect the car once I reconnect it after cleaning the contacts?

One last question, does the ECU have a specific earthing point?

Have you cleared the fault codes and found that they come back?

May just be stored/historical.

I have cleared codes but shows again.

Also the LED that shows fuel, time and mileage sometimes goes blank but reappears on on a restart,

Can anybody post a step by step guide to resetting the ECU to basic original settings with I believe 0.0 adaptation.

Engine ECU of both BMD and BME engine codes of 1.2 HTP in 2007 have no permanent 12V power connection, so disconnecting battery and/or the ECU connectors will have no more effect than simply switching the car off and removing ignition key does.

Edited 1 May1 May by Breezy_Pete

Wildly unlikely to be anything to do with the engine ECU, in my opinion.

Wish I had an idea what it might be instead.

Has anybody any ideas?

Where are the earth points for the ECUs?

On the strut turret right beside ECU, just above ABS module.

With your scan tool, if you can, scan module 09 'central electrics' or even better, look at live data from it, particularly voltages on terminal 15 and terminal 30.

I would check and clean all earths. It may be that under normal load the battery is fine showing 12.6v but when cranking under extra load a poor earth can cause voltage to drop for enough time to trigger codes. Check the earth/terminals at starter motor etc as well. Does the car turn over at a decent speed?

Alasdair

I will live scan later but earths are good, all clean and an extra earth run to engine block and one to strut top mount bolt by main battery body earth.

Starts/ cranks fine so sure battery is good and it is newish, under1yr old.

Where is the comfort module?

Above accelerator pedal on RHD car. Lower dash trim has to come out for access on mk1.

Much easier to scan than to eyeball physically.