Thread: D2/2004 Auto TD5 - speedo out of sync with the BCU... Helppp!!

Hey all... I'm in a bit of a pickle here 😕😕😕😕 Between the mechanic and the auto electrician I now have a D2/2004 Auto TD5 that has 777K on the speedo... rather than 235K when I left it with them. And for the 2 weeks they had it I doubt they clocked up the difference 😏 The speedo value does increment with travel though I suspect not by true kilometres. Apparently when undertaking some basic wiring for switches etc. they inadvertently created an issue in the ECU?/BCU? that resulted in the keys having to be re-registered after having to do the 'magic key dance' (4code entered by key) to get the car mobilised and started. Runs fine though i gotta get the speedo back to what it should be. The speedo reading was initially flashing though he turned this off (Nanocom probably). Some forums indicated after 16 restarts it will right itself... well not in this case. Land Rover independent mechanic appears clueless on this topic.

I'm sure not many out there would have first hand experience on recovering this situation... if you do - your advice will be gold and super appreciated. thanks...

Correct, Extract from RAVE

Odometer update
The BCU can be programmed for one of two options:
Option 1 – no odometer error warning.
Option 2 – odometer error warning.
In order to provide an LCD flash request to the instrument pack via the communications link, the following inputs are checked:
Ignition state.
Instrument pack odometer value (via the communications link).
BCU odometer value.
The function is only active when the ignition state is on. The maximum allowed value is 999,999 miles (1,608,999 km).If the instrument pack odometer value is greater than the maximum allowed value, the maximum value is assumed. The BCU odometer value is stored in EEPROM. If 16 identical values of the instrument pack odometer reading is received consecutively, the instrument pack odometer value is compared with the BCU odometer value. If the consecutive readings from the instrument pack differ, the BCU odometer value is incremented accordingly. If the BCU odometer value is less than the instrument pack odometer value by up to 10 km, the BCU odometer value is set equal to the instrument pack odometer value.
If the odometer warning option is enabled, and the contents of the instrument pack odometer value buffer is identical to, or greater than BCU odometer value ± 10 km, the BCU sends an LED flash request to the instrument pack.
In the event of a communications link failure, this function will be unable to operate.

So you’ll get 777km on both and won’t be able to go back!!

I’d hazard a guess they fried your original BCU some how and put a second hand one in with 777km and it synced to the Instrument pack??

You can read the both BCU and IP reading separately with a Nanocom and this will tell you what higher etc.
I’d be taking it back to them and having them rectify the problem or coughing up for either a new IP with lower KM??

I’ve just purchased a set from here with lower km to replace a faulty BCU in my D2 (gazk on here) excellent service!!

Land Rover Discovery 2a - Instrument Cluster With Bcu - 2003-2004