Should i bother fixing the O2 sensors in my 2003 Town and Country if my catalytic converter is going bad?

SOURCE: p0420 code 1996 chrysler town n country 3.8 v6

p0420 code is catalytic convertor low efficiency.

SOURCE: P0420 and P0430

The AF sensors are uupstream and the O2 down stream. The car' s computer tests them and it is saying your cats are bad. If you have a scan tool you could look at the data and see what the sensors are seeing. The Af sensors are the ones that control the fuel ratio in the car while the O2's just watch. AF's would be the one to change but there is no garuatee that the codes won't come back.

SOURCE: P2097 Error code in 2006 Dodge Grand Caravan, which O2 Sensor?

The one before the catalytic, on the side where cylinder # 1 is at. close to the exhaust mag.

SOURCE: i have a trouble code P0141 for a 2003 chevy

This will be an after the cat designation.

ZJ Limited

• 17989 Answers
• Posted on Jul 03, 2011

SOURCE: I have a 2004 sable.

When you detected one code P0174 - System Too Lean (Bank 2), this basically means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is generally the side of the engine that doesn't have cylinder #1.

Note: This DTC is very similar to P0171, and in fact your vehicle may show both codes at the same time.

Symptoms: You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.

Causes: A code P0174 may mean that one or more of the following has happened:
The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
There could be a vacuum leak downstream of the MAF sensor.

Possible solutions include:
In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace if necessary
Check for a dirty fuel filter and proper fuel pressure



Bank 2/Sensor 2 is at the bottom of the engine as you look in from the bumper. It is installed in the exhaust pipe just below the catalytic converter. The Bank 1/Sensor 2 is at the same location on the back of the engine below the firewall.

P0430 means Catalyst System Efficiency Below Threshold (Bank 2) basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms: You will likely not notice any drivability problems, although there may be symptoms such as a rough/hard idle when cold.

Causes: A code P0430 may mean that one or more of the following has happened:
The catalytic converter is no longer functioning properly
An oxygen sensor is not reading (functioning) properly
There is an exhaust leak

Possible Solutions: First, inspect for exhaust leaks. Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.


Hope this helps.