Hi Guys,

We have an 06 Reg Fiesta Ghia 1.6 TDCi with possible ECU fault.

It's just had a new battery fitted. The car starts/runs fine for 10 mins or so then all electrical items start failing...power steering, abs light illuminates, heated screens stop working then eventually battery light comes on. If the engine is switched off, it will not restart due to no juice in the battery.

I've got an ELM327 Bluetooth code reader and it shows these faults.....

P0620: Generator Control Circuit

P1934: Unknown code - More information may be available on the web

P0500: Vehicle Speed Sensor

U0121: Unknown code - More information may be available on the web

U0140: Unknown code - More information may be available on the web

B1318: [Mitsubishi] Valve actuation.

The car has been into Ford as it broke down one day. Please see the attached photo.

I've had the ecu tested by a company but they were unable to find a fault, but also said they were unable to test it in "real time", as if it were fitted to the vehicle so couldn't rule out a software/processor fault.

Has anyone any ideas what the cause could be?

Grateful for any info.

Thanks in advance.

Was the fault present before the battery was fitted. And what made you replace the battery.

Have you had the alternator checked

A low battery will usually throw those fault codes and illuminate the dash like a Christmas tree.

I had a similar problem on my a4 TDI. Sometimes car wouldt start. Woul crank but not turn over. Eventually the battery would go flat trying to crank it and it would throw those fault codes and illuminate the ABS, airbags battery lights etc on the dash.

When I hooked up my diagnostic I couldn't connect to ECU so I looked there and because water was getting in there was corrosion on the wiring. I rewired it and problem solved.

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Sounds like the garage don't know what there doing, think you need to start again diagnosing from the beginning. So, now it's non starter, you need to charge battery up first. Then get a voltage check done at various points, do you have a charger and multimeter?

my first thoughts were the alternator or the battery. do the lights flicker when on full. have you fitted aftermarket speakers or a boom box. check your connections on this. i don't know if they still use a part exchange on alternators these days.

What type of battery was fitted?

Sounds like a bad earth somewhere, check all the heavy duty leads from battery to chassis and all the small ones where they bolt to the body. Take them off, clean and replace.

Lead acid battery instead of the required calcium type will cause these issues.

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