1999 S70 Code ECM 4020, Cel, ETs..[solved by 9441116 brake position switch RR]

[RickHaleParker]

For shorts you can test at one end of the harness between two different wires. You should also check between one wire and a ground. Keep in mind ground wires are connected to ground so they will show shorted which is normal.

For opens you can get some real long leads ( which most people do not have) and connect at each end of the same wire OR you can intently short two wires at one end of the harness then test the two wires for the intended short at the other end with short leads. If you cannot detect the intended short at the other end it is because one of the two wires is open.

[smacknab]

Hey Rick,

Sorry to disappoint but I didn't end up testing the wires. I went to a couple junkyards this weekend and realized how easy it is to drop the gas tank, and pulled a spare fuel tank pressure sensor off another 99 NA for $5.

Then I went home and dropped the tank on my car, cleaned everything up, checked pretty thoroughly for cuts in the wires or vac lines and decided to swap in the junkyard pressure sensor. I figure its not that hard to go back and drop the tank again. I'll monitor it to see if a CEL or p0452 code comes back on.

Otherwise the ETS light has turned back on as well. I'm still getting the constant shut off issue when filling the gas tank. And I think my immobilizer related issue has gotten worse over the last day or two, I'm having to flip the key to pos2 then back the zero before attempting to start the car. Otherwise it'll crank-no-start or start up and immediately stall.

[RickHaleParker]

I'm still getting the constant shut off issue when filling the gas tank.

Plugged air vent in the fuel filler tube. The displaced air is trying to come up the same path the fuel is going down. Pushing fuel into the pump nozzle. It is like taking a full 2 liter bottle and turning it upside down with the cap off .. gulp gulp gulp. Take the gas cap off and look around the edge, you will see the air vent. You could of dealt with this when you had the tank dropped.

[smacknab]

Is the the little hole, about 1/4in in diameter? I poked it out with a pick and checked the whole filler neck when I had it out, but I'll take another look.

[abscate]

And I think my immobilizer related issue has gotten worse over the last day or two, I'm having to flip the key to pos2 then back the zero before attempting to start the car. Otherwise it'll crank-no-start or start up and immediately stall.

Classic immobilizer behaviour with a 99.

Have you tried restarting it after a 3 second wait when it stalls

[smacknab]

Yeah if it stalls i pull the key and try again and it starts up. If it's the immobilizer, is that often fixed just by swapping the immobilizer antenna ring? Part number Volvo 9442961

[abscate]

Yeah if it stalls i pull the key and try again and it starts up. If it's the immobilizer, is that often fixed just by swapping the immobilizer antenna ring? Part number Volvo 9442961

The ring rarely fails but I do have a spare if you want to try it.

That behavior is the 'key in too long' behavior you get when you bypass the security system by permanently installing a chip near the reader and then using a cheap non-chipped key as your primary.

[smacknab]

Weird I don't know if one of the previous owners would've done such a thing.. the keys seem original to me atleast based on their age. I'll try the other key to see if it makes a difference.

[smacknab]

Swapped in a junkyard immobilizer, cleaned the contacts with electrical connector cleaner, and connected/disconnected it multiple times as I read on here that can sometimes break out build up on contacts. I also tried the full battery disconnect for 30+ minutes tip. Still no noticable improvement on that front.

The p0452 hasn't come back yet. But i've had the battery disconnected so many times this week I don't know if I've really given it a chance to come back.

[abscate]

Remember the evap drive cycle rules ( good luck following them)

Throttle between 1/4-3/4
Fuel tank between 1/4 - 3/4
No full throttle at all
No AC
At least 15-30 minutes town driving
Do not exceed 60 mph