156 V6 Odometer fail

[singlespeeder]

Hi peeps,

The digital display on 156 V6 odometer/tripmeter is not displaying anything, so I'm thinking that it's going to get pinged on that when it goes for it's WOF next week. I initially thought it was a blown backlight bulb, so removed the speedo and changed the bulb, but no difference. Am I right in thinking if I replace the gauge unit with a working one, then the odomoeter reading is stored somewhere else and theoretically eveything should be sweet again?

TIA

[bazzbazz]

No, the 156 does not have a body computer so it stores the Odometer reading in the Speedometer unit. So whatever mileage is on the new Speedometer, that's what it will show.

All cars after the 156 with body computers (147, GT, 159, Giulietta ect) store the Odometer reading in the Body Computer, so the correct reading is always shows if you change the Instrument Cluster.

[Citroënbender]

According to the WOF regs, the speedo must work, but odometer - if the car is already registered in NZ - doesn't matter.  Same as annual recertification in many Australian states. 

Bazz - I once stopped a Sele 147 stone dead by attempting to drive it with no dash cluster!  So I had always assumed there was a great degree of interdependence between the body module and the cluster. 

[bazzbazz]

Think of it this way - The Body computer is a bit like a power board, with all other ECUs (Electronic Control Unit) plugged into it. All are integrated into the Body ECU, all are dependant on it, and all are linked through it.

[Citroënbender]

I just assumed it was so you couldn't drive the car with the cluster unplugged and therefore not log miles on it.

[Craig_m67]

I always thought the mileage (km, yes) was stored both in the speedo head AND in the ECU somewhere.. Which is how they can tell if a car has been clocked?

Otherwise I'm going to wipe 240K km off Sooty, I don't reckon anybody could tell 🙂

[bazzbazz]

Not on the 156.

Otherwise I'm going to wipe 240K km off Sooty, I don't reckon anybody could tell 🙂

Yeah, it's not like anyone would notice or contest it.   

[Citroënbender]

SingleSpeeder - how did you go with the WOF?