Dash Backup Battery For Clock

[craigcaf]

Sorry to dig this one up again, but looking through old posts I got confused. My clock has an error and reads garbage, e.g 35:43.

I am assuming that the backup battery is dead, but is it (1) in the dash instrument cluster, or (2) in the dash ECU in the footwell. Are there one or two backup batteries for the systems.? Graham's bible seems to suggest it is in the instrument cluster, but then I found a past post suggesting it is in the dash ecu in the footwell.

C

[craigcaf]

Anyone?

[VARLEYHYD]

Miles in dash ecu
Clock in pod

Not 100% on this but check you have the correct battery first , then change the battery very carefully with the ignition ON for the miles, maybe not neccessary for clock but best do same.

Hope this works ok for you

GV

[Hollowpockets]

I've got the same clock error, was told it was the dash ecu in the footwell I need to send off for repair.

[EvoOlli]

Sorry Varley,

the clock is in the Dash ECU. The POD itself is relatively dumb.
There's a CR2032 battery in the Dash ECU which let the clock run even when the main battery is down. But there's a big problem with the clock-chip: If the time is wrong like in the example above, there's no RESET or anything else possible for the normal user. Even if you replace the Battery you can't set the clock when it's outside the 0...23:0...59 range. A big software development fault.

Miles are stored in a chip which doesn't need power, so under normal circumstances the Mileage won't be lost.

If the clock is outside of the normal range, i fear you have to send in the DASH ECU to (for example) Paul Smith, http://pselectronicsolutions.co.uk/. He has the equipment to reset the clock to normal values.

Good tip: When you want to change the CR2032 leave the ECU on the loom and switch ignition on.

[craigcaf]

Thanks guys. I spoke to Paul Smith this morning, and dash ECU will be off back to him for clock reset following a new battery. He's also going to check the 5V supply in the ECU to see if that is causing the hunting on readings on the dash. He thought it could be that or an earth, but first to rule out the ECU.

C

[craigcaf]

ECU back from Paul - and clock all set correctly. The dash values hunting he reckoned was the earth in the passengers footwell. I disconnected here and noticed that from the factory the eyelet ring terminals were soldered - presumably to prevent corrosion. It all looked good, but I cleaned up all ring terminals with emery on both sides of the footwell. Also replaced the M10 bolt with a stainless one and used only stainless washers and nyloc nut.

First drive today and all dash ECU reading steady as a rock. Water temperature back to normal no hunting, no spurious alarms and all is right with the world :-).

C

[paul1962]

Craig, just out of interest did you try the ecu after you got it back from Paul and before cleaning up the passenger footwell connections ?

[craigcaf]

To be honest no. I spoke to Paul about the problem and he was pretty certain it was the earth, he did check the stability of the readings on the bench and found no problems, so the conclusion was the ECU internal power supply was OK.

C