Description in title. I am decent at fixing stuff, but new to volvos, trying to help a buddy with a dead car. Heres the situation:

- cranks but wont start, at first just no spark, was fixed for like 2 weeks from just disconnecting/reconnecting ignition coil wires, but now no spark + no fuel
- all the normal dash lights come on when key is in position 2 so i don't think the main fuse is blown, or something like that
- when you attempt the OBD process (key in position 2, diag pin in slot 2, press diag button) we get totally nothing. the light comes on while the button is being pressed, but the codes never blink out. we tried pressing the button twice for 1-2 seconds each time, and once for 2-3 seconds, neither method was successful. i watched several youtube videos and im pretty sure i am doing it correctly
- all the fuses in the driver footwell look fine, which seem to be labelled as the ones that control the actual engine ignition/fuel stuff (are there more fuses somewhere else relevant to this issue? It seems like 740s have fuses under the ashtray in the center console, but the volvo manual for the 240 doesnt say anything about fuses except for the driver footwell ones. I dont have access to the car right now, will check/update)

I traced the issue all the way to the ECU, and found a pinout here for the plug, and tested pin 9 for power with the ignition turned. The ground on pin 19 was fine and grounded, but no power on pin 9.

Is there a relay or something that can fail preventing power to the ECU/EZK? It seems like both the ECU and EZK are not getting power and thus not responding on the OBD diag test on either position 2 or 6

Any thoughts or suggestions are welcome.

Thanks!

 

There should be a fuse in the engine compartment mounted on the front left fender - near the coil. This 25 amp fuse supplies power to the fuel injection system. Check the fuse and make sure there isn't corrosion as water tends to get to this location.

 

the 240 LH2.4 ECU gets its power from one half of the fuel system relay (the other half powers the fuel pumps). the ICU (EZK) should get its power right from the ignition key. that wiring diagram is for a 740/940 so there's some minor differences.

 

uh, can you take a pic? cause I didn't see one

 

the fuel injection fuse is rigth behind the battery, its a blade type fuse, the factory fuse holder was a slim white plastic thing but these often burn up with age, and may have been replaced with an inline fuse holder (I usually use marine style waterproof ones as that area can get wet driving in heavy rains).

see 240 Volvo Engine Management Fuse for some pictures ...

 

update - problem solved - it was those weird cylindrical fuses being corroded and not making contact

 

you should replace ALL the ceramic fuses with the brass/copper ones from Flosser, these are far superior to the usual tinplate ones. Flosser only sells them in boxes of 100, but lots of folks on ebay will sell you a reasonable sized assortment of them, they are also used by 70s/80s/90s Mercedes ...

 

just for posterity this fuse wasnt there on a 1992 240. literally all the fuses in the car are just the 16 cylindrical fuses in the driver footwell area

 

on late 93 240s, they added a fuse block right on the positive battery terminal, with 4 "PAL" fuses (kinda boxy things, not very common), one of which replaces that 25A ATO fuse.

on 740/940's, the 25A EFI fuse is in the main fuse panel under the ashtray, but I don't believe it was *EVER* moved to the main fuse panel on a 240.



ah, I read that page I'd linked more carefully, and I guess I never had a 91-93(early) 240, but yeah, it moved the EFI circuit to that main fuse panel.

as I said above, I recommend changing ALL those fuses to the newer brass/copper Flosser fuses.... when you do this, clean the spring contacts with a soft clean pink pencil eraser, that will remove corrosion without removing whatever plating is left on the springs. sometimes I go so far as to put a drop of Caig DeoxIT D100 on both ends of each ceramic fuse, this will reduce corrosion and improve the electrical contact (I did this on my mercedes that uses the same fuses, not sure I ever bothered to do it on our old 240)