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97 Cadillac Catera P0140, P0140, P0161 O2 Sensor Codes - Bank 1 & Bank 2, Sensor 2 - Fix for Smog Inspection at 127,000 Miles

Model: 97 cadillac catera Fault Code: P0140 Posted: 2009-03-31 21:39

I own a 1997 Cadillac Catera with persistent OBD2 fault codes: P0140, P0141, and P0161. These relate to Bank 1 and Bank 2, Sensor 2 on both sides of the engine. The vehicle has reached 127,000 miles and I'm facing a smog inspection soon. I'd like to know whether replacing the oxygen sensors is necessary or if there's a simpler fix. Can someone clarify what steps to take to resolve these codes without costly repairs?

Related fault codes
P0140P0141P0161
Comments (5)
Anonymous 2009-04-01 07:56

Start by checking the fuses and wiring harness connections for the oxygen (O2) sensors. A scanner that can monitor live O2 sensor readings is essential to diagnose whether the signals are functioning properly or if they're stuck in a faulty state.

Anonymous 2009-04-01 13:31

Is the fuse located under the hood? I'm currently using an OBD2 scanner, but it only shows 'inc' (indicating no signal) when I check the sensor readings—does this mean the sensors are not working or just poorly connected?

Anonymous 2009-04-03 07:20

It's best to inspect all relevant fuses, both under the hood and inside the vehicle. If you don't have access to a scanner that can monitor live O2 sensor data, consider borrowing one or having a professional perform the test at a repair shop.

Anonymous 2009-04-03 12:57

I followed your advice—checked the connectors for both O2 sensors. One was loose and I reconnected it properly. For the other, I disconnected and cleaned the connector inside the wiring harness. After clearing the check engine light (CEL), I've driven for two days with no return of the CEL. Thanks so much for the help—it's been a relief!

Anonymous 2009-04-04 15:49