'95 850 Cruise Control points of failure?

[dazbooker1973]

mines not working
read code in cruise control module and it has code 122 which is no speed signal but theres no code in engine ecu for no speed signal and these share the same wire
any ideas

[dazbooker1973]

check these out
what do you think

[1337]

I have a 1998 V70, and the cruise control has failed yet again. I've confirmed that the pump works and the vacuum line is good. The brake and clutch sensors appear to be adjusted correctly. The speedometer works fine. The wiring for the cruise control switch (on the wiper stalk) looks fine.

Two questions:

1. Is there a way to "bench test" a cruise control relay? I replaced the cruise control relay with one from pick-n-pull, and this didn't fix the cruise control. I wonder my car's relay and the pick-n-pull relay are both bad!

2. The 1995 850 documentation (https://www.volvoclub.org.uk/tech/servi ... System.pdf) suggests diagnosing cruise control failures with this diagnostic port:

diagnostic-port.jpg (15.44 KiB) Viewed 1898 times

My car is a 1998 with full OBD-II support, so I don't have this diagnostic port. I also don't have a CEL or anything like that. Can I read these cruise control codes somehow on my car? (Perhaps I need a VIDA-compatible reader?)

[tryingbe]

I have a 1998 V70, and the cruise control has failed yet again. I've confirmed that the pump works and the vacuum line is good. The brake and clutch sensors appear to be adjusted correctly.

How did you run the test for the pump, vacuum lines, and the brake/clutch switches?

[1337]

I have a 1998 V70, and the cruise control has failed yet again. I've confirmed that the pump works and the vacuum line is good. The brake and clutch sensors appear to be adjusted correctly.

How did you run the test for the pump, vacuum lines, and the brake/clutch switches?

Pump: Jumped it to 12v battery, it turns on. I guess I should also hook it to a vacuum gauge and make sure it makes enough vacuum.

Vacuum: Attached a vacuum pump (a Mityvac hand-pump designed for bleeding brakes) to the cruise vacuum line. When I applied vacuum, the gas pedal went down. It seemed to hold the pressure, too.

Pedal switches: All I did was to visually inspect that the switches are only triggered when the pedals are pressed. And, when driving on the highway, if I hold the brake and clutch up with my feet, the cruise still doesn't engage.

[tryingbe]

https://www.matthewsvolvosite.com/downlo ... vo_850.zip

I'd skip to page 9 and run the test, this test will bypass the relay.

[1337]

Thanks! This is to test the vacuum system in a more complete way?
(I attached the cruise control PDF from that zip file.)

It looks like the basic idea is to remove the cruise control relay, and then to jump some of the terminals that were plugged into the cruise control relay?

Has anyone on the forum done this series of tests before? Does it work as advertised, or are there some gotchas?

[tryingbe]

Test works as described in the factory repair manual.

[1337]

Thanks! This is to test the vacuum system in a more complete way?
(I attached the cruise control PDF from that zip file.)

It looks like the basic idea is to remove the cruise control relay, and then to jump some of the terminals that were plugged into the cruise control relay?

Has anyone on the forum done this series of tests before? Does it work as advertised, or are there some gotchas?

The directions say to fabricate a jumper to go between some of the pins. Any advice for what raw materials to buy to make the jumper? Or, does someone sell something that works just right?

[tryingbe]

Couple piece of a wire with both end stripped?