Speedometer problem

[Tuns]

Hi Guys 

Fixed one issue (rear trim) and another issue appears. 

So recently (about two months ago) I had an issue with the car not starting and all the lights on the dash turning on and going crazy. It turned out I had the fault code U1900 which requires the soldier joints repairing on the main board because they have gone dry and cracked. I did this, all worked fine. Been working fine ever since. 

So yesterday I'm driving down the motorway. All fine. I then notice the speedometer is creeping up instead of going down when I slowed down. It's currently pointing just past the 150mph mark when turned off. 

Has anyone come across this before ?

 

Cheers 

 

 

[DaveT70]

Whoever repaired the cluster has over installed the needles to the dials on rebuild (the needles have to be removed to get to the solders) and they are sticking, take it back to them to rectify, they should've offered warranty

[Tuns]

20 minutes ago, DaveT70 said:

Whoever repaired the cluster has over installed the needles to the dials on rebuild (the needles have to be removed to get to the solders) and they are sticking, take it back to them to rectify, they should've offered warranty

Thanks. 

I actually did the repair myself 😂

Do you know why the dial would work fine for months then suddenly develop this problem ?

[mjt]

I have no detailed knowledge of the cluster circuit but one thing that comes to mind is that the steppers that drive the gauges are multi-phase motors and loss of one phase might cause the affected motor to only drive in one direction. Since the dreaded lead-free solder is used throughout it's possible you still have some dodgy joints somewhere on the board. Maybe the act of removing and refitting the needles might have weakened one.

[RL123]

The lead free solder should be removed and not just reflowed as it is unlikely to last.

the needles do need to be replaced accurately and are just push fit.

left ours to the professionals to resolder all joints and re-assemble 

[Tuns]

18 minutes ago, mjt said:

I have no detailed knowledge of the cluster circuit but one thing that comes to mind is that the steppers that drive the gauges are multi-phase motors and loss of one phase might cause the affected motor to only drive in one direction. Since the dreaded lead-free solder is used throughout it's possible you still have some dodgy joints somewhere on the board. Maybe the act of removing and refitting the needles might have weakened one.

Quite possible. I'll have to get the board out again and have a closer look. 

8 minutes ago, RL123 said:

The lead free solder should be removed and not just reflowed as it is unlikely to last.

the needles do need to be replaced accurately and are just push fit.

left ours to the professionals to resolder all joints and re-assemble 

To be fair I only reflowed the joints so I'll get the board out and have another look at it. Hopefully it's a relatively easy fix 

[mjt]

I would doubt the problem is with the reflowed joints, although it's definitely advisable to remove all the old solder using, e.g., solder wick and resolder with tin/lead solder. The gauges are all driven from the on-board microprocessor based on canbus signals received from the various sensors so if the problem was in the main connector joints you'd still be getting lots of canbus error DTCs.

[Tuns]

Engine management light has come on. I'll get it hooked up to the machine and see what fault code it will give. Might shed some light on the problem. 

[DaveT70]

9 hours ago, Tuns said:

Engine management light has come on. I'll get it hooked up to the machine and see what fault code it will give. Might shed some light on the problem. 

Sounds like the repair has failed then

[StephenFord]

I also had mine 'professionally' repaired, no issues since. I can appreciate the satisfaction of doing it yourself, but for £60 odd, I would consider getting someone who does it for a living have a go...