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[DrAndyB]

Come to get in the car to come home this evening and speedo has stopped 

Fuel and temp guage OK, cluster lights OK, and trip computer OK but:

• No Speedo
• No Odometer or Trip counters
• No Cruise control
• No Distance related functions in trip computer

Any thoughts ?

I don't have any warning lights (TC or ABS).  Just Speedo not move when drive off.  When car is started you see needle flicker slightly (as I think it has always done).

Car is a 2.5CDX V5 Manual (Mini Face Lift).

[Doctor Gollum]

Sounds like the speed signal out put from the ecu has a break in it. Which is probably the only ABS fault which won't raise a code

This is the Blue/Red wire which runs everywhere... radio/sunroof/speedo/cruise/suspension level control/xenon ecu/engine ecu...

[DrAndyB]

Sounds like the speed signal out put from the ecu has a break in it. Which is probably the only ABS fault which won't raise a code

This is the Blue/Red wire which runs everywhere... radio/sunroof/speedo/cruise/suspension level control/xenon ecu/engine ecu...

Sounds like a nightmare.  Where would one start ?

I was going to make sure Speedo was seated right by popping it out and in and go from there.  It has been warm, so it maybe that ?  I do hope this is not the start of the end for my poor baby  .  62k on the clock she is too young to hang her boots up 

[Doctor Gollum]

I would start by checking the continuity from the abs ecu to the engine and cruise ecu plugs and between the engine and cruise ecu plugs.

The second will tell you if the wiring is intact to the speedo as this spurs off the cruise feed (or vice versa)

If both of these check out as unbroken, then your fault is most likely the abs ecu. It is a rare failure mode, so don't be disheartened by it

[DrAndyB]

I would start by checking the continuity from the abs ecu to the engine and cruise ecu plugs and between the engine and cruise ecu plugs.

The second will tell you if the wiring is intact to the speedo as this spurs off the cruise feed (or vice versa)

If both of these check out as unbroken, then your fault is most likely the abs ecu. It is a rare failure mode, so don't be disheartened by it

Ok will do.  Where are the ABS, Engine and Cruse ECU's located ? And are they ok to unplug ? 

[Doctor Gollum]

Abs to rear of power steering reservoir, engine ecu in triangular fuse box, and cruise ecu is unit with short cable to throttle body.

Only need to test the blue wire with the red tracer.

[DrAndyB]

Abs to rear of power steering reservoir, engine ecu in triangular fuse box, and cruise ecu is unit with short cable to throttle body.

Only need to test the blue wire with the red tracer.

Cheers.  Will check over weekend.  I am hoping it was just the sun and heat just enough for one of them connections to be iffy.  They have remained plugged in and not touched since car came out of factory 

Fingers crossed.  Will report back.

Thanks.

[Kevin Wood]

It's also possible this signal has shorted to ground somewhere so might be worth checking for that.

[Doctor Gollum]

It's also possible this signal has shorted to ground somewhere so might be worth checking for that.

Continuity from any of the three plugs above to battery negative will test this

[DrAndyB]

Abs to rear of power steering reservoir, engine ecu in triangular fuse box, and cruise ecu is unit with short cable to throttle body.

Only need to test the blue wire with the red tracer.

Just to check, assume its OK to unplug the ECU.  Key it not in the car !

The ABS and Cruise plugs look a pain to access 

[Doctor Gollum]

Disconnect the battery if in doubt, but it will be fine. Just don't turn the key past 0

[Lizzie Zoom]

Sounds like the speed signal out put from the ecu has a break in it. Which is probably the only ABS fault which won't raise a code

This is the Blue/Red wire which runs everywhere... radio/sunroof/speedo/cruise/suspension level control/xenon ecu/engine ecu...

Sounds like a nightmare.  Where would one start ?

I was going to make sure Speedo was seated right by popping it out and in and go from there.  It has been warm, so it maybe that ?  I do hope this is not the start of the end for my poor baby  .  62k on the clock she is too young to hang her boots up 

I have only had that happen to me once after taking out the dash unit for maintenance.  I had not seated it in correctly, so once I had done that all was ok.

Your comment about warm weather could be a clue; yes things expand when they get hot, so it is possible the unit has moved just off away from its connection.

[Doctor Gollum]

That would only knock out the speedo and trip

Cruise and fuel computer also not working suggests a more fundamental issue...

[DrAndyB]

Disconnect the battery if in doubt, but it will be fine. Just don't turn the key past 0

OK, so I disconnected battery to be sure.  I have NO Continuity from Pin 9 on the ECU Plug to the Blue with Red Tracer wire on the Cruise control Plug.  Pin 9 seems to be the one from the ECU (according to the wiring diagram) but I checked all the ECU pins and none ring through to the Cruise wire plug.

I've attached a few pics.

I've not checked ECU Plug to ABS unit plug yet, is it the rectangular plug on the back of the ABS Unit? (Which looks a pig to get at ! - 2nd to last pic) or can access any wires in the other round looking connectors revealed when I took battery out ? (last pic ?)

Pin 9 ECU

BLRT wire on Cruise unit

Diagram

ABS Plug ?

Any use ?

[DrAndyB]

OK, so I have continuity from ECU Pin 9 to the BLRT Wire in the more accessible plug !!  (I assume this is Plug X3 in the Diagram).