Hey guys, got a 1997 Buick Lesabre po133 po440

[spikey007]

My check engine light came on. I went to autozone for their "free diagnostic test" they plugged in the OBD 2 scanner, and got 2 codes... One of the codes is PO133 they said that the oxygen sensor could be defective, or the fuel system is running rich or lean.

And now the other code is a po440 which is a "large EVAP LEAK" . I was wondering if anyone could give me any ideas at all to where there could be a leak, and where i could check.

Any help at all would be greatly apprieciated!!! I have a 1997 BUICk LESABRE 3.8 (series 2 VIN k) .

[stuzman]

Originally Posted by spikey007

My check engine light came on. I went to autozone for their "free diagnostic test" they plugged in the OBD 2 scanner, and got 2 codes... One of the codes is PO133 they said that the oxygen sensor could be defective, or the fuel system is running rich or lean.

And now the other code is a po440 which is a "large EVAP LEAK" . I was wondering if anyone could give me any ideas at all to where there could be a leak, and where i could check.

Any help at all would be greatly apprieciated!!! I have a 1997 BUICk LESABRE 3.8 (series 2 VIN k) .

P0133 says that the upstream O2 sensor is slow reacting. Could be sensor, exhaust leak, frayed wiring or possibly skewed MAF sensor. A scope would be ideal method to check the sensor where a cross count and a response test utilizing a snap throttle.

For your P0440 code, the ECM has detected a large leak (greater than 0.020"). The leak could be anywhere from the fuel tank (maybe fuel cap) to the charcoal cannister. Start by looking around the cannister for split vacuum hoses, etc. If memory serves me correctly, the vent solenoid has been known to leak. If nothing can be found visually, a smoke machine test would be used.

[spikey007]

Originally Posted by stuzman

P0133 says that the upstream O2 sensor is slow reacting. Could be sensor, exhaust leak, frayed wiring or possibly skewed MAF sensor. A scope would be ideal method to check the sensor where a cross count and a response test utilizing a snap throttle.

For your P0440 code, the ECM has detected a large leak (greater than 0.020"). The leak could be anywhere from the fuel tank (maybe fuel cap) to the charcoal cannister. Start by looking around the cannister for split vacuum hoses, etc. If memory serves me correctly, the vent solenoid has been known to leak. If nothing can be found visually, a smoke machine test would be used.

thank you so much for your advice!!! greatly appreciated!!