I have a 2000 Subaru Outback (purchased it new), automatic transmission and now have 96,000 miles on it. Recently the CHECK ENGINE light comes on and stays on even though the car runs fine and is getting normal gas milage. I purchased an Equus code reader and it indicates an error code of P1133. This particular error code is not listed in the official Subaru manual for this particular year equpped with automatic transmission. It does list P1131 and P1134 codes and mentions they are associated with front and rear oxygen sensors. If anyone has any additional info on this error code P1133 I would certainly appreciate more information. You can email me direct if desired: bentonjim@aol.com

 

JIM in MISSOURI

here is a diagnostic chart for p1133 from your year vehicle.

 

matt

p1133.pdf

Check with the dealer there may be an oustanding recall on the front (A/F) sensor

Get your VIN # and phone it in and see

 

SEA#3

I notice in the attached file that it says to shake the wiring harness and monitor the voltage to see if it moves more than 8 volts. Why would shaking the harness have anything to do with voltage unless Subaru is saying that the harness could be faulty(shorted)? Am I reading that correctly?

It's not necessarily that the harness is shorting pins, it's probably more likely to fail open, or if there's any corrosion in there it will exhibit more resistance than is ideal.

 

P1133 is in the OE manual for '00OBW; it says DTC P1133 - FRONT OXYGEN (A/F) SENSOR HEATER CIRCUIT HIGH INPUT. (sorry about the caps-cut&paste).

 

As already mentioned there was a recall on the front o2 sensors where they'll replace it for free (some piece can break off or something I think); so if it hasn't been done yet and your vehicle was included might as well get it done.

But if it's not free I think my front sensor was about $60 and it is not that hard to change. My first move would be to change it because it is a consumeable and and a 2000 model should be about done anyway.

Is the info the same for auto transmission as for manual.

I would expect so but I hate to troubleshoot and then find

there was a difference.

or could you post it for an auto'

 

thanks

Richard

Seems the use of a fuel-air ratio sensor is specific for the MT Legacy.

 

I had this same code P1133 and the OBDII said however (LOW) below and I was able to clear the code by replacing the sensor. Used a Denso 234-9018. Do not buy a UNIVERSAL O2 sensor. It will NOT work!! Needs to be OEM on this car. Believe me I tried it. The OE unit made by Denso can be bought at auto parts stores and is the same as the dealer OE part. 3x check that they sell you the right unit for a MT Legacy which is not the same at the AT one.

 

It seems the diagnostics pathway attached above is just for a high condition.

 

My Legacy had 115k, started to smell a little rich, and then on cold mornings, idle RPM would be very high for a few minutes and then when the car warmed was fine. Seems that both the sensor heater was messed up as well as the actual o2 sensor part.

 

The sensor came out easily despite the awkard angle.

 

I spend hours on mind so wanted to at least share my experiences.

Bosch( the originators of O2 sensors) will also work with no problems.

 

Let the car idle a few minutes and hold the bung with an open end wrench, then turn sensor.

 

O.

One of the things I'm in the habit of doing when diagnosing an o2 heater fault, or any heater related fault, is ohm test the heater in the o2. Open or shorted heaters are common, and computers can set a variety of heater circuit codes.

Tom

This statement below is correct. If you have the MT (manual transmission) version of the subaru outback you have the dual inline cats.

 

You must replace the front sensor with a factory OEM to get everything working right. Be prepared to pay $150 to $180 for it.

 

That said the rear is just a plain oxygen sensor and an oem good equivalent will work.

 

>>>Seems the use of a fuel-air ratio sensor is specific for the MT Legacy.