1996 Volvo 850 having troubles

volvo

#1

I just bought a Volvo 850 wagon. I knew that the car had trouble and I got a great deal on it expecting some work to do. My dad and i were told that it needed an Air intake master sensor. we checked it and it seemed fine, and did some reading up online, and then checked Cam position sensor, Crankshaft position sensor and both are fine. we discovered that there is no spark going to the coil, and no power going to the fuel pump each of which we checked and seem to be fine. the last problem we found is that none of the gauges and lights in the dash are not getting power (all the fuses are good), external lights, radio, sunroof and windows all work fine. We did put a newer battery in the car, it turns over fine and did run before sitting for 2 years after a stalling issue that the previous owner didn’t want to bother fixing.

the car has 140K on it and is in good condition, my dad has owned and worked on many Volvo’s over the years and is very confident in working on them but we are both very puzzled about the lack of power going to the coil and fuel pump.

thanks for any help,

Carsten


#2

The only thing I know about Volvos is that they used to be boxy, were owned by Ford for awhile, are now (I think) owned by VW, and never seem to be keeping up with traffic. But I’ll try to suggest a few ideas anyway.

Does the car have a security system? Shutting off power to the ignition and the fuel pump sound like typical security features.

Does the car have an inertial cutoff switch, to shut the engine and fuel pump down in an accident? Your owner’s manual or repair manual should refer to this if the car has one. It should also tell you how to reset it.

Beyond that, It’s a protocol of simply working backwards using a schematic with wiring diagram until you find the missing power. A Volvo dealer should be able to print the schematics for the relevant circuits if they’re not in the repair manual. If you don’t have a repair manual, getting one will be the first step in the process.

Post back. We do care.


#3

Time to locate a factory service manual, or a good wiring diagram for this model, and trace some circuits. You may have a relay problem somewhere, but will be beating your head against the wall without a guide. Electrical systems for these cars are too complex.


#4

thanks for the input, my dad is being very reluctant about the security system causing the power shut off because he hasn’t had that happen before with a Volvo or with any of his Saab’s, but i’ll look into it. I will be getting a new repair manual for the car on Tuesday until then were going off what he remembers about the wiring system (generally speaking) and what we read online. I’ll update, when/if we find thing more useful.


#5

Volvo is now owned by the Chinese firm Geely.


#6

Hmmm, the plot thickens…


#7

As I recall they bought the company 4 or 5 years ago. I know ford first acquired Volvo in 97.


#8

Your Dad might not have experienced this with security systems on other Volvos and Saabs, but the present car could have an aftermarket system. Or some other unusual thing that got added to the car in its long life. (The 1994 940 my son has in El Paso right now has a kluged-in manual switch for the A/C compressor, I guess because the thermostatic switch(?) failed.)


#9

We got the repair manual in the mail today and we are going to reset the alarm system in hopes that it will help.


#10

no change when we reset the system so now were going to completely shut it off, we’re thinking electrical and i think we might go through the systems them one by one.


#11

Okay so we’ve narrowed the problem in the dash down to the ignition switch, and we’re pretty sure that the Air mas Sensor is toast.