92 740 Turbo Wagon, Speed Sensor & Cruise Issue

otis44 · Post by **otis44** » 08 Dec 2008, 23:11

I've got a 1992 model 740 turbo wagon, 150k +- miles. The speedometer/odometer and cruise control are all non-functioning on this car. I have isolated the speedometer/problem to the cluster itself, as another cluster works as it should. My question is even though I am getting a signal to the dash from the rear differential sensor will the speedometer not working stop the cruise control from engaging.

Based on some test, electrical and otherwise I am pretty sure I have eliminated all of the usual suspects for the cruise problem, vac. lines, brake switch, servo, etc. The diagnostic test for the cruise throws the code 1-2-2 (I think) I may have the number wrong but its the one that refers to no speed signal.

I have swapped the vacuum pump and the cruise module with parts from a 940 wagon, but at this point I don't actually know if they are good. I know both vacuum pumps run if 12v is applied and I have my doubts that both control modules are bad. The servo will stay deflated if manually compressed and capped off. I can swap clusters again and try that I just didn't want to if I am missing something else, which is highly probable. Thanks in advance for some help

Post by **billofdurham** » 10 Dec 2008, 12:33

Welcome to Matthew's Volvo Site.

The code 1-2-2 on the cruise is "speed below minimum/no signal". However, that code is set every time the ignition is switched on and will remain in the system until the speed of the vehicle has been greater than 22mph for at least 15 seconds. To test properly you need to take the car out at 22mph+ for 15 seconds+ then test for fault codes before switching off the engine. If 1-2-2 is still there the control unit is not receiving a signal.

Try this and let us know what happens.

Bill.

otis44 · Post by **otis44** » 10 Dec 2008, 22:50

Thanks for your reply. I did pull the code the way you described. I posted this question on another site, and was advised the cruise control signal came from/through the speedometer and not directly from the speed sensor. My speedometer is dead but I know I am receiving a signal from the differential. I guess if I want cruise control, it's repair or replace the cluster. Thanks again

Post by **billofdurham** » 11 Dec 2008, 11:08

That is correct. I was just curious to see if you had a genuine code or only the code that always sets.

Bill.