: oops! Replaced mass air flow - not oxygen sensor in 97 cat

12-23-05, 10:39 AM
OOPS! Regarding the last post, I just found out from my mechanic,I replaced the mass air flow not the oxygen sensor in my 97 catera!

12-24-05, 01:35 AM
As long as you have to really replace the Mass Airflow sensor and not the O2 sensors, there's no harm done. But if mistakenly replaced it instead of the O2 sensors, then it's a costly mistake.

12-24-05, 09:56 AM
Just don't try to install one in place of the other! :D

12-28-05, 10:20 AM
I replaced the mass air flow and then the car ran good for a while. Now the check engine light is on and the autozone guy said the P0153 code is for an oxygen sensor.

The mass air flow filter was what was 444.00 retail, and we paid $333. wholesale at the GM dealership.

The ABS and TC light are also on.

I disconnected the battery and now when I drive the check engine light is off, but the other two are still on.

I am hoping getting the new tire will help with that . What do you think?

12-28-05, 11:55 AM
From the manual

The heated oxygen sensor (HO2S) produces a voltage that varies between -100 mV and 900 mV under normal operating conditions. On the Catera, the full operating range of the HO2S circuit is approximately from -406 mV to 1124 mV. The Engine Control Module (ECM) monitors this voltage and determines if the exhaust is lean or rich. The oxygen sensor voltage is high when the exhaust is rich, and low when the exhaust is lean. The ECM constantly monitors the HO2S signal during the closed loop operation and compensates for a rich or lean condition by decreasing or increasing the injector pulse width as necessary. If the oxygen sensor is slow to respond to any changes in the exhaust oxygen content, this DTC will set

Probably a weakening or contaminated sensor.