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

[smacknab]

Turns out the starting issue was a corroded wire from the solenoid to the starter, not sure why I hadn't checked there.

P0452 hasn't returned since swapping in the junkyard fuel tank pressure sensor.

Today i swapped in a new brake pedal position sensor and after 100 miles of mixed driving I no longer have a CEL or p1041 code and my cruise control is back.

More importantly my ETS light is gone! I read recently that the brake pedal position sensor going bad can trip the ETS light, atleast on a 99. I'll keep monitoring it but glad that this saga is tentatively solved.

Some of what tipped me off was when I brought my car to my indie to have them mate a new throttle body into the car. They said they tested my old one, and the extra backup i had in the trunk and they both gave the same readings as the new one.

[abscate]

He has tertiary Volvo disease....backup parts of backup parts.

[smacknab]

He has tertiary Volvo disease....backup parts of backup parts.

Seems like there's no more topic is solved button, anyway to change the title to something like ETS light caused by brake pedal position sensor/p1041?

[abscate]

Part 9441116 if you have DTSC option on your car
$80 for the ATE version new, a good pick and pull item

[smacknab]

Part 9441116 if you have DTSC option on your car
$80 for the ATE version new, a good pick and pull item

Yeah I wish I went for the ATE one, for some reason I thought volvo electronics would be needed here, but the Volvo one is literally an ATE in a blue box. Better yet I wish I grabbed one off a junkyard car, probably would've cost me $5.

Thankfully I was able to return the new throttle body so I've saved a bunch of money on this and now I know my back up throttle body is good for the future too.

Only issue I'm still having is occasional hunting idle and the rpm still dips when coasting to a red light in neutral. Maybe there's some vaccine issue I'm unaware of?

UPDATE: RPM fluctuations were caused by cracked and disconnected crankcase vent hose. It was new so i didn't think it would be a problem, but it was a cheap one off amazon so turns out it was junk. I ductaped the cracks and got it back on and now there are no RPM dips while coasting and no hunting at idle. Will replace properly with a volvo one soonish.