Speedo Quits

[Flyer]

I am camped next to an 2005 Discovery whose speedo intermitttently quits. When it quits the cruise control and exhaust brake also quit. Any suggestions? He is heading home from Fort Nelson BC (AlCan Hwy) with some mountains between here and home. Thanks.

[Flyer]

I am camped next to an 2005 Discovery whose speedo intermitttently quits. When it quits the cruise control and exhaust brake also quit. Any suggestions? He is heading home from Fort Nelson BC (AlCan Hwy) with some mountains between here and home. Thanks.

[Hitchhiker]

Probably the sensor, some are on the rear axle. Others on the tranny.

["007"]

Withall the road vibrations on that road I would look for loose ground some where on frame or battery. Could be battery feed also.

[chasfm11]

Guessing that the Discovery is on a Freightliner chassis and has wiring similar to mine, here is a "shot in the dark".

We had intermittent speedo problems too. Fortunately for us, the check engine light would also set occasionally with an erorr message saying "lost communication." It turned out to be the plug on the ECM. The fact that your neighbor is getting multiple problems when it fails makes it sound similar to ours.

Here is what I suggest:
- go to Radio Shack and buy DeOxit. It is a kit of contact cleaner.
- pull the output cable from the ECM (mine has just a few white wires in it) and carefully examine the contacts. You are looking specifically for an oxidized surface in the ECM or in the plug. Use the DeOxit on both sides of the connector and then replace it firmly in the ECM. Make sure it latches tightly.

The other end of the long cable comes out in the electrical compartment below the driver's seat in ours. It is possible that the problem actually is there but the way ours is put together, getting to that connector is really hard.

A couple of points of interest:
- according to Allison, if the speed sensor in the transmission is failing in any way, you get error lights, shift inhibit and other symptoms.
- the speedo data is transmitted from the transmission to the ECM which controls the cruise control. The ECM output travels over the CAN (controller area network) buss to the instrument package in the dash.

At least that is the way it works on ours.

Good luck.

Charlie

[Flyer]

Thanks for the inputs. My neighbor has headed south and I am heading north. Hope he took my advice and becomes an IRV2 member.

[MonacoMama]

I giggled everytime I read this headline ....
..and I thought..."Thank Goodness...most men shouldn't be wearing a speedos anyways!" ...and then I read the post ....silly me...darn it anyways!