View Full Version : "97 DeVille B1S1 Oxygen Sensor

11-16-08, 10:34 PM
My latest code on my '97 DeVille is the good old P0135 (B1S1). If this sensor proves bad and I have to replace it,

1) Can I get to it without unbolting the cradle/frame? I'm assuming B1S1 is in the exhaust manifold on the firewall side.

2) The part no. AFS109 was suggested to the owner of a '96 Seville with a bad B1S1. Same part no. for a '97 DeVille?

Thanks again in advance, everyone.
Matt ('97 DeVille)

11-16-08, 10:44 PM
1) Can I get to it without unbolting the cradle/frame? I'm assuming B1S1 is in the exhaust manifold on the firewall side.

It is on the firewall manifold and is a little difficult to get at, but you don't need to drop the cradle.

It should be the same on the '96 & '97.

11-16-08, 10:45 PM
Remove the strut tower support and coil pack. Get yourself a 7/8" crowsfoot wrench (3/8" drive), a mess of 3/8" drive extensions, a universal joint, and a good ratchet. You may have to move the coolant lines a bit to get access. It's tricky. But with a little patience, a few band-aids, and if worse comes to worse, a little penetrating oil, it's possible. If you want more access remove the rear cam cover. But it can be done without. Just make sure the manifold is dry (or close to it) before re-firing the engine.

Part numbers will be the same for LD8 / L37 engines. I forget which year they changed the wiring but I know a '93 has a different O2 sensor connector than a '97. Good luck and keep us posted!:thumbsup:

11-16-08, 11:11 PM
Another way to gain a little more clearance is to use the turnbuckle method. Disconnect the passenger side torque strut. Replace the drivers side with a turnbuckle and pull the engine forward an inch or two. That worked great for me when I changed the blower motor on my '97.

11-19-08, 12:33 PM
Thanks for all the great tips! I'm compiling a notebook of them for future reference.
Funny thing, this P0135 code appeared immediately after a tune-up (new plugs and fuel filter), then "disappeared" (never went to"history") after subsequent starts. There was no "tell-tale" warning.
I will start a thread where "phantom" codes are discussed; guess I should be happy, right?

Thanks again,

11-19-08, 12:42 PM
I'd like to discuss "phantom" or "disappearing" codes in this thread. Again, thanks to all who have replied to my previous thread.
Immediately after putting in plugs and a new filter, I was getting the P0135 code (B1S1 oxygen sensor). On subsequent starts, the code vanished; never went to "History" even. There was no "tell-tale" display.
I'm not complaining, but what's going on? Have any of you good folks ever had a code (not a cold lol) one day, and it's gone the next?
Matt (mdogg) '97 DeVille N*

11-19-08, 04:01 PM
Can't explain it vanishing unless it was cleared. It should have gone to history.