1996 Volvo 850 P0133 error code, "

Bank 1 sensor 1 should be the one on the exhaust manifold, before the cat. You replaced the right sensor, but as that didn't work, check all these other conditions that may set that code.

P0133 OBD-II Trouble Code Technical Description
Oxygen Sensor Circuit Slow Response (Bank1, Sensor1)

What does that mean?

This involves the front oxygen sensor on Bank 1. This code indicates the engine air fuel ratio is not being adjusted by the oxygen sensor signal or the ECM as expected to do so, or not adjusted as often as expected to do so once the engine is warmed or under normal engine use.

Symptoms

You will likely not notice any drivability problems, lthough there may be symptoms.

Causes

A code P0133 may mean that one or more of the following has happened:

* The oxygen sensor is faulty
* The wiring to the sensor is broken / frayed
* There is an exhaust leak

Possible Solutions

The simplest thing to do is to reset the code and see if it comes back.

If the code comes back, the problem is more than likely the front Bank 1 oxygen sensor. You will likely wind up replacing it but you should also consider these possible solutions:

* Check and fix any exhaust leaks
* Check for wiring problems (shorted, frayed wires)
* Check the frequency and amplitude of the oxygen sensor (advanced)
* Check for a deteriorating / contaminated oxygen sensor, replace if necessary
* Check for inlet air leaks
* Check the MAF sensor for proper operation

[quote] Also, where is the rear window wash resevoir located on the 96 volvo wagon? [end quote]

It uses the same reservoir as the front. That bottle should have two washer pumps.

Bob, Ken and all of the 2CarPros team,
Thanks for all your input.
As I suspected, there was an exhaust leak first repaired about 11 months ago at a local shop. The welding job failed and was leaking and thus the Bank 1, Sensor 1 error code for the O2 sensor. The code has been cleared and not returned since 2nd repair. Also thanks for location of the rear washer resevoir. Both motors checked out OK but a rear check valve to the rear port has failed. Now replaced and rear washer works fine.
Thanks Again

Glad everything worked out well for you. Come back anytime..