Cruise Control Out on '93 940 Turbo wagon

Post by **Eddystone** » 06 Sep 2018, 18:32

I've been chasing a CEL issue and the only fault I can find is in B2 Cruise Control.

I'm reading a 1-2-2 which is "Speed has not exceeded 22mph or no speed signal.

Looking at the schematics, it looks as if the speed signal to the cruise control comes from the instrument panel/speedometer. Right?

Now, I did notice a week or so ago that the cruise control was not functional. Just won't come on.

I have also noticed that my usually DOA fuel gauge is working.

I'm thinking I should remove my instrument panel and at least reheat all the old solder joints.

Anyone think that might help? Other suggestions?

Glen

Post by **RickHaleParker** » 06 Sep 2018, 18:47

Which engine?
Which engine management?
Which transmission?

Post by **Eddystone** » 06 Sep 2018, 21:28

No offense, Rick, but if it's a '93 940 Turbo in Pennsylvania, the engine has been identified. So has the engine management system and the transmission since it was only sold in one configuration. I know forums have a protocol that basic information should be supplied with questions, but I think I've supplied everything anyone who knows that model would need to know. I'm looking for someone who has experience with the 940 cruise control, not a scolding. I supplied the exact code and symptom and only asked a general question. Do you have any experience with the cruise control in RWD Bricks? I would greatly appreciate any advice you could offer.

Post by **Eddystone** » 06 Sep 2018, 22:03

FROM THE BRICKBOARD FAQ: "When the cruise in my son's 95 940 failed, I performed the diagnostics thanks to the OBD unit under the hood. It returned "no signal from speedometer". The speedometer and odometer were working fine. I tested the output from the speedo using a multimeter and it "appeared" to be working. After making sure everything else was working, I finally replaced the speedometer and cruise returned to normal. It so happens that the speedometer receives a sine wave signal from the rear axle sending unit and converts this into a square wave, with frequency proportional to rear wheel velocity, to serve as a the input into the cruise control computer. If this does not happen, no cruise control. I do not have an oscilloscope which would have made quick work of this diagnostic. Anyway, if your cruise dies and you get this diagnostic report while your speedometer appears to be working fine, consider that the internal wave conversion might have failed. This means a replacement speedo."

ALSO: B2 terminal code 1-2-2 No speed signal, or has not exceeded minimum 35 km/h. This code means the signal from the speed sensor has not been received. It's usually not a failure yet since the system erases the codes every time the ignition is turned off and when you turn it back on the initial status is no signal from the speed sensor since that only comes once the speed exceeds 22 MPH. If you leave the diagnostic connected and go for a ride and then perform this test BEFORE you shut down the ignition the code should come back 1-1-1. If it does not then this code table should be used to identify the issue.

Voltage feed (12V between terminals 10 & 11)
Ground location (0 ohm between terminal 10 and ground)
Speed signal
Wiring in circuit (speedo to control unit; speedo to rear axle)
With rear wheels raised and one rotating slowly,voltage at terminal 13 should oscillate 12V to +1.5V

I'll check these things tomorrow and report on the results.

93Regina · Post by **93Regina** » 07 Sep 2018, 12:42

Eddystone wrote: ↑06 Sep 2018, 18:32....

I suspect I have over a million miles driven, without cruise usage....although all three vehicles I drive have a working cruise, I very seldom use it.

But, for those wanting to know how to fix it: Crusie Control on Volvo 700, 900 and 90 Series

93Regina · Post by **93Regina** » 07 Sep 2018, 12:44

Eddystone wrote: ↑06 Sep 2018, 22:03B2 terminal code 1-2-2

One could evaluate this, with a good multimeter...don't ask how

Post by **Eddystone** » 07 Sep 2018, 14:15

93Regina wrote: ↑07 Sep 2018, 12:42
Eddystone wrote: ↑06 Sep 2018, 18:32....
I suspect I have over a million miles driven, without cruise usage....although all three vehicles I drive have a working cruise, I very seldom use it.

But, for those wanting to know how to fix it: Crusie Control on Volvo 700, 900 and 90 Series

I use the cruise control frequently.

Your link is from the same thing I quoted above, just from a different source. I think the 1-2-2 is a red herring and may be normal under the circumstances as I tested it. The cruise control doesn't function, but I'm not to concerned about that. I am concerned with the Check Engine Light CEL on the panel. Can't seem to lock down what's causing it. My gas gauge has been intermittent for years, and I'm sure that problem is in the instrument cluster. So, I'm going to pull the cluster and re-heat all of the old 1993 solder joints and see what that does. Then go on from there...

Post by **Eddystone** » 08 Sep 2018, 18:41

This may not work for everyone depending on what the actual root cause of your problem may be, but I want to document this for other searchers. I want to suggest that pulling the 25-year-old instrument cluster and re-heating the solder joints is probably an important preventive maintenance task because it eliminates numerous potential variables.

My original symptom was a Check Engine Light and a malfunctioning cruise control on a '93 945 Turbo. My gas gauge had been intermittent and had finally stopped working. I removed the instrument panel and re-heated all of the solder joints. Some of them looked a bit suspect, and the fuel gauge connections showed an awful lot of ancient solder flux.

Afterwards. The fuel gauge worked as it should. I cleared the CEL by disconnecting the battery (because the codes I had were not enough to indicate where the problem was) and the CEL did not reappear and the cruise control started working again.

There is a speed signal that originates in the speedometer in the gauge cluster and feeds into the cruise control. I believe that I may have been missing this signal since I had a 1-2-2 code on port 6 and no codes 1-1-1 on port 2. I believe all this signal does is confirm that you are traveling above 22 mph below which the speed control will not engage.

So, again, my basic message is that pulling the 25-year-old instrument cluster and re-heating the solder joints is probably an important preventive maintenance task because it eliminates numerous potential variables.

dm635 · Post by **dm635** » 10 Sep 2018, 08:16

On my '91 740 I had an intermittent starting problem caused by the park/neutral switch at the bottom of the shifter. It may be the same switch that's on your 940. For the time being I jumped the switch wiring. After that my cruise stopped working. Listing this as a possible issue.

There is a danger issue jumping/bypassing the switch though. It will start in any gear. I need to get my problem resolved. Waiting to just get another shifter assy, as the switch and shifter require some disassembly to get to the switch. Would rather have one on hand in case I run into problems taking the one in the car apart.

93Regina · Post by **93Regina** » 10 Sep 2018, 19:45

dm635 wrote: ↑10 Sep 2018, 08:16...park/neutral switch...jumped the switch wiring...There is a danger issue jumping/bypassing the switch though. It will start in any gear...

Danger?....are you suggesting humans are senseless/brainless beings, when they start an engine?

Lots of people want to disconnect the inhibitor switch.