BBCode Formatting Updated by MX-3.com, March 18th, 2006 (Photo Links Still Invalid)Again, stolen from PT user Leska:
Replaced the rear oxygen sensor and thought I'd post pictures with instructions.
DIAGNOSIS (OBD-I Vehicles 1993-1995)
The Check Engine light was coming on and after jumping the TEN & GND pins, it was reporting Code 23 & 24......
23 RHO2S inactivation error
24 RHO2S inversion error
REMOVAL
The right oxygen sensor is located behind the engine about 4-5 below the exhaust manifold. It's a 4 wire sensor that points towards the passenger side of the car. Access to it is partially blocked by the frame crossmember (the beam on the left with the 3 holes).It looks like this....
Rear Oxygen Sensor (26KB) [LINK BROKEN]
To make this job quick and easy, remove the 6 crossmember bolts and remove the crossmember. They are quite short and have a 17mm head. Once you have it removed, I suggest using a crow-foot wrench to unbolt the sensor. The 7/8 wrench fit best. All the crossmember, bolts, suggested wrench and new sensor look like this.....
Parts and Tool(35KB) [LINK BROKEN]
The easiest access to the oxygen sensor is right through the middle of the pipes with the angled wrench head pointing left. It's a great fit and allows about 5 to turn it or hammer on it if necessary. Looks like this......
Best Wrench Angle(22KB) [LINK BROKEN]
The connector has a lever on the engine harness side of the connector that you push in while pulling the connector apart.
REPLACEMENT
Make sure to apply anti-seize compound to the threads before install. Some sensors come with it pre-applied. My replacement sensor came with a tiny tube of gold compound. Looks like this....
Applying Anti-Seize (27KB) [LINK BROKEN]
Screw it in before plugging the connector in. It's suggested to tighten to 35 ft/lbs. The sensor has a crush washer as a seal, so make sure to tighten it good and snug.
After you plug it in, reinstall the crossmember with it's six bolts. I'd suggest using Anti-Seize on these as well for future removal. Torque these bolts to 69-90 ft/lbs.
Finished product looks like this.....
New Sensor Installed (26KB) [LINK BROKEN]
A few other tools I used but are not necessary are an impact wrench and 1/2 torque wrench. I wouldn't shy away from removing the crossmember if you just have hand tools though. The bolts are short and come out rather easy on my 7 year old PGT. A 1/2 breaker bar should work fine. This is what I used....
Optional Tools (30KB) [LINK BROKEN]
Expect the whole job to take under 30 minutes after the car is jacked up. I'd say 15 minutes with an air wrench.
There you go
NOTE: Front oxygen sensor is very similar but much easier. Just remove the plastic s shaped air intake behind/above the radiator to gain access to it and the connector.
Codes associated with the Left sensor are as follows....
15 LHO2S inactivation error
17 LHO2S inversion error