I havea 99 Saturn SC2 and the P0133 error code came up. It says it's a "O2 circuit slow response (Bank 1, Sensor 1). I replaced the upstream O2 sensor (by the exhaust manifold) but it didn't fix it... Does anyone know if the downstream one is hard to replace and where it is located? I can't find it. Thanks! Pete

Marvin

• 85242 Answers
• Posted on Apr 26, 2009

SOURCE: Does my 1999 Mercury Mystique have 4 O2 Sensors or am I wrong?

the sensors before the catalytic converters are the upstream sensors, the ones after the after the catalytic converters are the down stream sensors, Ford calls them the Catalyst efficiency monitors.

juggernautxt

• 145 Answers
• Posted on May 06, 2009

SOURCE: Code: P0133 - O2 Sensor Circuit Slow Response Bank 1 Sensor 1

is this a 4 or 6 cylinder?
if a 4 cylinder it will only have 2 o2 sensors
V6 will have 4 o2 senors which the sensor will be the right side of the engine first sensor.
1st sensor on exhaust, I recommend if you change one change all, as this will make the computer when it rechecks the system you have all clean/fast responding sensors.

if you have a slow response it means the sensor is dirty and not reading well, which is usually caused by minor misfires that the engine computer dismisses, so a tune up would be recommended too.

SOURCE: Getting PO141 trouble code when scanning! Car '03 accord, 2.4 ltr

http://www.honda-tech.com/showthread.php?t=2385730 good luck!

Testimonial: "Thanks! I figured out po141 is the sensor that goes into the cat after studying few books and trial and error. Part store gave me the wrong info 1st. "

SOURCE: have p0130 and p0133 codes 98 toyota tacoma

I would check the O2 sensor, and if it checks bad, replace it, and clear the trouble codes. If the light comes back on, you may need to check further. .

SOURCE: OBD II code P0133 (O2 bank 1 sensor 1) which

It is the front sensor, if your car is the type that has 2 front sensors it will be the one closest to the timing chain / belt (left hand side of engine)