I have a 98 3500 5.9. O2 sensor code came up. Bank 1 sensor 1. Which one is that? There are 4 correct? What happens driving around with a bad o2 sensor?

Thanks.

Lee

 

On any engine bank 1 is the side with the #1 cylinder. Sensor 1 is the one before the catalytic converter (upstream). So in your case, it's the driver's side before the cat.

 

Dodge vans (96-03) only use 2 sensors, one before the cat and one after. So the one at the cat inlet is the one that has the malfunction.

 

Is this something I should change right away?

 

Yes it should be changed very soon. The PCM uses this one to decide how much fuel to give the engine. With out it working the PCM will stay in Open Loop which will use more fuel and cause the catalytic converter to clog up sooner than you want.

 

Thanks.

Lee