SpeedoMeter stops working, Need some help..

Post by **Matty Moo** » 23 Jun 2012, 20:08

jpeisker wrote:
I have two 850s and both have had the ABS controller fail (solder joints). With the ABS failed or even removed I never had a speedometer failure, so I don't understand why people say there is a connection between speedo and ABS. I believe the electronic version of the odometer is tied to the ABS controller, but no the mechanical odo.
Jim

I have never seen a 96 and up have a functional speedometer with the abs module removed.

Post by **jmmxc** » 23 Jun 2012, 23:16

Wiggling the key makes all these go away and the speedometer starts working again. I'll be replacing this switch soon.

You may be have a point. I gave a hard bang to the dash above the cluster, that may have "put in order" what ever is intermittent. I would be interested to take a look at the switch as well. Please indicate the procedure, later on.

I have never seen a 96 and up have a functional speedometer with the abs module removed.

This may be, I had driven the car for about a month w/o the ABS module when I had to fix it, no issue with speedo. Even before the ABS fail and thereafter the speedo works OK._Could this have to do with a particular series, engine, or submodel within this family? Otherwise I am bemused by the fact that the speedo works with no ABS as suggested.

So far it is holding up...
jmmxc

jpeisker · Post by **jpeisker** » 24 Jun 2012, 18:16

An excellent writeup on ignition switch replacement found here:

www.matthewsvolvosite.com/forums/viewtopic.php?f=1&t=37398

IPD also has a good replacement procedure for that part number. Download from their part detail page (OEM 9447803).
You can buy a replacement switch in the $55-60 range from both IPD and FCP. Looks like VolvoPartsWebstore has it for $49.

Regarding the ABS controller, Matty Moo is probably right in that the speedometer will not work with the module removed; that assertion was from memory and it's getting worse with age.

However, I am very certain that the speedometer can work when you have the ABS module connected but the warning light is on due to the common solder joint failure. This I am sure about because I distinctly remember this from both cars, driving around with the ABS light on while I could still read speed. That was my main point; I should not have thrown in the bit about the module being removed since I am now unsure about that.

What may interest you is that a symptom of a bad ignition switch is both ABS warning light and the speedometer not working. It is possible that if you have a bad switch, replacing it can solve both speedo and ABS problems.
Jim

Laird_Scooby · Post by **Laird_Scooby** » 24 Jun 2012, 23:46

jpeisker wrote: What may interest you is that a symptom of a bad ignition switch is both ABS warning light and the speedometer not working. It is possible that if you have a bad switch, replacing it can solve both speedo and ABS problems.
Jim

Hmm, i'll bear that in mind Jim, thanks. In fairness (and with no direspect) i wonder how applicable that will be to my 1989 although it's very relevant to the O/P. It appears to be fairly easy to get to on mine, just pop the instrument cluster out (2 screws) then the back of the ignition switch can be reached easily. I've noticed a couple of times (on the only journey it's done with me, coming home on the day i bought it) that if i switched the ignition off then on again that the ABS light would stay off. To that end, i'm halfway tempted to remove it, strip and clean the contacts and refit.

Maybe something for the O/P to consider, if they have a spare switch it could even be temporarily unplugged, the spare plugged in and operated with a screwdriver or similar. Obviously if the car was driven the key would have to be in the steering lock/igniton switch and turned to the run position to unlock the steering but could be worth a go.

jpeisker · Post by **jpeisker** » 25 Jun 2012, 19:50

Hi Dave,
Sorry, didn't mean to confuse you on this. I was specifically addressing this post topic of jmmxc's 1996 model 850 as he reported problems with both the speedometer and ABS module.
I can't offer meaningful advice on your 1989 model 740 as they are likely different and I haven't looked into your car's wiring.
Jim

Post by **jmmxc** » 27 Jun 2012, 22:10

An excellent writeup on ignition switch replacement found here:
https://www.matthewsvolvosite.com/forums ... =1&t=37398

Thanks for the link. The switch does not appear to be difficult to get to. I am making plan to check it.

Regarding the ABS controller, Matty Moo is probably right in that the speedometer will not work with the module removed; that assertion was from memory and it's getting worse with age.
However, I am very certain that the speedometer can work when you have the ABS module connected but the warning light is on due to the common solder joint failure. This I am sure about because I distinctly remember this from both cars, driving around with the ABS light on while I could still read speed

It seems to me that there may be some odd electrical relationship between the speedometer logic and the ABS, however thus far the speedo in my car has worked w/o my having a functioning ABS. BUT I do not mean to argue this point to death, I am just pointing out the oddity in what seems to be a largely accepted cause and effect consensus on the subject.

I finally had pulled the cluster out (one more time), I cleaned the contacts and check the solder joints and I even refreshed a large joint. Then I packed things up. No problem. I road tested the car thereafter and now 4 days on..., the speedo still performs fine.

Intermittent electro-mechanical failures tend to be the worst to deal with unless I throw money at all the suspect parts.
Guess I have to wait and see what develops next.
jmmxc

Post by **Matty Moo** » 27 Jun 2012, 22:18

You can have a faulty module and still have a speedometer reading. It all depends on what pins inside are cracked and the severity. It can go 50/50 in either direction. They all fail the same way as far as the cracked joints go, its just which ones crack first.

Post by **jmmxc** » 04 Jul 2012, 20:27

.....It can go 50/50 in either direction. They all fail the same way as far as the cracked joints go, its just which ones crack first.

Yeap, I will go with that.
Has anyone gotten a hold of either a detailed diagram or schematic of the ABS module.
I would be interested to take a look. Also I will need to replace the whole ABS because I think I have issues with wiring going inside the pump sitting on top of the abs block._ Is there a detailed DYI procedure available?
Thanks for all your suggestions.
jmmxc.

Post by **Matty Moo** » 04 Jul 2012, 21:54

Internal schematics are proprietary to Teves. You won't find them anywhere.

You have two options on the pump wiring.... Either replace the entire assembly with a 98 unit or re wrap the wires with rubber tape. Based on Longevity and hassle, go with the rubber tape. . Rubber taped my 96 and it was good to go.

Post by **Fish stick88** » 04 Jul 2012, 22:17

+1 Matty Moo, Did you even have to weigh those options out?

SpeedoMeter stops working, Need some help..

Re: SpeedoMeter stops working, Need some help..