96 850 o2 sensor

Danonly55 · Post by **Danonly55** » 10 Aug 2018, 19:44

I replaced my up stream o2 sensor a month ago and It has thrown the same code twice in the last week. Is there anything else that could cause this ?

Post by **wizechatmgr** » 10 Aug 2018, 20:18

My feeling would be an fuel/ignition/leak type issue.

Post by **RickHaleParker** » 10 Aug 2018, 23:46

What is the code?

There are lots of thing that can cause O2 and catalytic efficiency codes when the O2 and catalytic converter are in working order. Wizechatmgr outlined them, something messing up the fuel/air ratio or preventing fuel from burning efficiently.

Post by **erikv11** » 11 Aug 2018, 07:24

If you installed the universal type sensor (even from Bosch), people have had a lot of problems with those. You need the pre-wired, genuine Bosch sensor. Similarly, this part is known to be counterfeited frequently on the eBay market.

Post by **misha** » 11 Aug 2018, 17:09

RickHaleParker wrote: ↑10 Aug 2018, 23:46 What is the code?

There are lots of thing that can cause O2 and catalytic efficiency codes when the O2 and catalytic converter are in working order. Wizechatmgr outlined them, something messing up the fuel/air ratio or preventing fuel from burning efficiently.

1st o2 sensor(upstream) can't throw cat efficiency code...that's the 2nd o2 task(downstream).

@ Danonly55....vacuum leak,exhaust manifold leak or even a tiny crack in flexi pipe between cat & exhaust manifold could cause the front o2 sensor code...dirty maf too...because the oxygene which Maf metered doesn't correspond with oxygene that o2 metered because one of those sensors are dirty.

Danonly55 · Post by **Danonly55** » 11 Aug 2018, 18:32

I purchased the Bosch sensor from IPD, 120$ Im thinking its a fuel burning issue, I bought the car at auction a few months ago and have not checked the plugs or distributor. You guys confirmed my thoughts. Thanks Guys. Any recommendations on plug type ?

Post by **misha** » 12 Aug 2018, 01:45

Cheap copper ones single prong NGK or BOSCH properly gapped...or original triple prong Volvo plugs.

Cap & rotor must be Bosch.

Post by **erikv11** » 12 Aug 2018, 08:48

What misha said!

Danonly55 · Post by **Danonly55** » 12 Aug 2018, 11:06

The code was P0133 #1 o2 sensor slow response

Post by **RickHaleParker** » 12 Aug 2018, 12:12

P0133 can be:
EFI-435 Front heated oxygen sensor (HO2S). Too slow
or
EFI-436 Rear heated oxygen sensor (HO2S). Compensation

EFI-435 Possible sources
uneven compression
air leakage in the intake system
air leakage in the exhaust system
faulty fuel pressure
defective front heated oxygen sensor (HO2S).

EFI-436 Possible sources
uneven compression
air leakage in the intake system
air leakage in the exhaust system
defective rear heated oxygen sensor (HO2S)
defective front heated oxygen sensor (HO2S).