Hey everyone,

new to the community... looking for some advice after just picking up a 1994 850 Turbo.

I went to change the turn signal stock on the steering column last night and by fluke the car shut off while running... ive spent many hours trying to diagnose the problem... see if any long time guys can figure this one out.

cranks... but no spark... no power at the sensors (ie injectors, maf, etc)... coil has power... ecu has power but doesnt send the signal to turn the main relay on to power sensors...

crank sensor checks out aok... havent check cam position sensor (how important is this?)...

no check engine light... but all other dash lights are on when u cycle the key... and stay on aswell...

any ideas?... if u need any extra info i can tell more.

thanks in advance.

 

Did you try pulling the codes?
http://www.troublecodes.net/Volvo/
Thats how to pull them.
The Cam sensor is very important. It will stop the car from running.
Check the plug good they usually fall apart.

 

Check for pressure at the fuel rail. Listen if your fuel pump is priming.

 

will do...

im just uncertain of how these ecu's operate. like the ecu turns the main relay on (the front one under the rad support) which powers injectors, maf, coil etc...
testing the crank signal was aok... (havent checked cam sensor)... but does the ecu need the cam position in order for the ecu to turn on those sensors? volvos do seem to crank for a second before they start...

if i crank it with the ecu not powering the sensors wont it just pull codes for all the sensors not being powered?... or perhaps maybe the cam sensor one will come back.

it was just a strange occurance how this all happened... was running fine parked... then just quit... then no spark...

 

fuel pressure aok... fuel pump primes and is on!

 

Oh whoops, I didn't see that you determined that there was no spark already.

Do you have any check engine lights?

 

ok. i cant even connect to the ecu... the self check in pin A2 wont give me any feedback nor does the ob2 plug under the ash tray in the car...

anyone?

 

Not to be captain obvious... but did you check the fuses? They are located in a box near the driver side firewall on top of the engine compartment. Also... Tech, wouldn't the check engine light come on while the key was in position 3 along with the other dash lights? That leads me to believe that someone took the check engine bulb out, or it is burnt out.. this actually happened to me on a chevy truck I purchased a few years back. Does this year 850 have the obd II? And if so, when you ran a diag on it, no codes came up at all?

 

it wont connect to computer to pull codes... the ecu is getting 12volts but im thinking its not turning on... fuses and relays check out...

im thinking ecu failure?

 

Very well possible but not common.
Try removing the computer and cleaning all the connections.

 

try the obd2 connector under the ashtray. you have to connect a switch between pins 3 and 5, and an analog multimeter in VDC on pins 3 and 5 also. When you put the key in position II, you should get 12V on the multimeter. Then close the switch for 1 second (the multimeter should show 0 volts while the switch is closed). When you release the switch the voltage should jump back to 12V. Then just look at the needle. It should start reporting error codes. If you don´t have any stored code you will get 1-1-1. Instead of a multimeter you can use a 12V LED if you have one.

 

My OBD-II port was under the coin holder (for US models?). Either way, it's right in front of the shifter, under whatever there is.

When you remove the ECU from its nest, be sure to remove the negative battery cable and wait at least 15 minutes to avoid permanent damage.

Good luck,


JPN

 

Yeah, under the coin holder. My mistake, sorry.

 

so... long time no post...

thought id give everyone the heads up!... dont ask me how... but by changing the turn signal stock on the steering column with the car running... the car died... as stated in my first post.... ran every check possible... turns out the ecu got toasted... picked up an ecu and it fired instantly...

never heard of that one before...

 

Volvo Technology, maybe[&:]?


JPN

 

believe it or not, electronics can go bad just like mechanical parts for no apparent reason.