1996 (corrected) 850 NA hot stalling

[850oldschool]

I'm quite skeptical that a fault with any of the other three sensors which are (potentially) bonded to the common ground at pin 28 could cause the accelerometer fault if the accelerometer ground is intact.

Of course that should be TWO other sensors, three total.

[RickHaleParker]

On that list a 433 code is "Front HO2S slow response", which actually seems much more likely to trigger a switch from closed to open loop operation than a knock sensor code. And just in case you aren't confused enough at this point and need a little more, on this list both of those codes are lumped together as P0331.

Hang on in the 90s Volvo used four different engine management systems. The code list are bound to have errors. EFI-433 is rear knock sensor Signal. Defective Knock Sensor or wiring.

Do us a favor, look at your VIN number then post digits 6 - 10, YV1LS_ _ _ _ _ .

[850oldschool]

5546T

That list I linked to here at MVS says clearly right at the top of the page: "CODES: 1996 TO 1998 VOLVOS", but it does seem to be crowd sourced.

I did several more tests today and confirmed that if the EFI-433 is active at startup it won't run in closed loop mode. Clearing the code magically wakes up the short term fuel trim. Tomorrow I'll try to grope around and see if I can reseat the connector on the knock sensor.

Not looking forward to lifting the intake manifold.

[abscate]

Knock sensors failures are really unicorns, I would skip that.

[850oldschool]

Knock sensors failures are really unicorns, I would skip that.

Most likely oxidation on the connector. All I had to do to get rid of the accelerometer code was reseat the connector. The last time I had my MAF plug off I looked at the pins and they were all dark with oxidation. I've got some Deoxit now and I'm going to start using it on every electrical connector I disassemble.

[850oldschool]

I was expecting to find a bunch of corrosion, but I found that both wires to the knock sensor had been severed. I could cobble something together with butt splices, but the wire stubs are pretty short to work with. Does anybody know where I could buy a new connector or a pigtail? I know it's a "junior power timer" connector. It's Volvo branded and the numbers don't turn up anything.

[RickHaleParker]

Rodent Attack!

The wiring harness is Volvo Part number 9442158. They can still be found.

There is a "upgrade" with the knock sensors integrated with the harness as one unit. It will cost you at least three times as much, Volvo part number 1270492.

5546T

B5254S, w/o EGR w/air pump, w/OBDII, w/elec. control evap, Motronic 4.4 w/Rulo., TLEV, 1996.

Eleventh digit:
1 = Torslanda, Sweden, 2 = Ghent, Belgium, 3 = Halifax, Canada.

[850oldschool]

Thanks, Rick! I've got one of those harnesses on the way. It was probably a squirrel. They're bad around here. I hope I can get it installed without lifting the intake manifold.

Your VIN decoding matches what I found. Hopefully one of the mods will take pity on me and update this thread title so I look less dumb... at least *slightly* less dumb!

Also, if somebody has a source or a part number for that connector by itself I'd love to have a few spares on hand. There are quite a few on this car.

[erikv11]

Junkyard for the harness and/or connectors - very, very cheap and you have several to choose from in Minneapolis.

[abscate]

Done!