P0420 on '98 V6 Contour

Bad cat or bad O2 sensor. Just means the #2 O2 sensort is seeing substantially the same as #1 O2 sensor. If it's the cat, it's a pricy proposition. Mine was just an O2 sensor.

Catalyst System Efficiency Below Threshold (Bank 1)

What does that mean? Basically this means that the oxygen sensor downstream (after) the catalytic converter on bank 1 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.

Causes A code P0420 may mean that one or more of the following has happened:

a.. Leaded fuel was used where unleaded was called for b.. An oxygen sensor is not reading (functioning) properly c.. The engine coolant temperature sensor is not working properly d.. Damaged exhaust manifold / catalytic converter / exhaust pipe e.. Retarded spark timing Possible Solutions The simplest thing to do is to reset the code and see if it comes back.

Next step is to measure the voltage at the oxygen sensor on Bank 1 (the rear sensor, or the sensor after the converter). The voltage should be low and steady (~200mV, depends on the vehicle). If the voltage varies (e.g. 100mV to 600mV) then it's time to replace the catalytic converter. 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.

This code will ususally turn out to be a failed catalytic converter. IIRC, there was an emissions recall to replace the catalysts on many V-6 Contours. Have your local dealer check OASIS to see if the recall is still in effect and if your car qualifies.

~On Wed, 08 Feb 2006 02:40:08 GMT, Father Guido wrote: ~ ~>Hi, ~>

~>I got an OBDII for Christmas and just got to try it out on my ~>daughters '98 V6 Contour. The code comes up as P0420, which the book ~>translates as "Catalyst System Effcieincy Below Threshold (Bank 1)". ~>

~>I assume something to do with the catalytic converter, but then again ~>maybe not. Anyone have any experience with this code and what we ~>should check next. ~>

~>Thanks in advance, ~>

~>Norm ~Bad cat or bad O2 sensor. Just means the #2 O2 sensort is seeing ~substantially the same as #1 O2 sensor. ~If it's the cat, it's a pricy proposition. Mine was just an O2 sensor.

Thanks for the info!

Norm

~Catalyst System Efficiency Below Threshold (Bank 1) ~ ~What does that mean? ~Basically this means that the oxygen sensor downstream (after) the catalytic ~converter on bank 1 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. ~ ~Causes ~A code P0420 may mean that one or more of the following has happened: ~ ~ a.. Leaded fuel was used where unleaded was called for ~ b.. An oxygen sensor is not reading (functioning) properly ~ c.. The engine coolant temperature sensor is not working properly ~ d.. Damaged exhaust manifold / catalytic converter / exhaust pipe ~ e.. Retarded spark timing ~Possible Solutions ~The simplest thing to do is to reset the code and see if it comes back. ~ ~Next step is to measure the voltage at the oxygen sensor on Bank 1 (the rear ~sensor, or the sensor after the converter). The voltage should be low and ~steady (~200mV, depends on the vehicle). If the voltage varies (e.g.

100mV ~to 600mV) then it's time to replace the catalytic converter. 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.

It's a '98 so I doubt if it would be covered, we've replaced at least one O2 sensor a couple of times now. Hopefully it's another, and not the cat convertor.

Thanks for the info and help.

Norm

~Father Guido wrote: ~> Hi, ~> ~> I got an OBDII for Christmas and just got to try it out on my ~> daughters '98 V6 Contour. The code comes up as P0420, which the book ~> translates as "Catalyst System Effcieincy Below Threshold (Bank

1)". ~> ~> I assume something to do with the catalytic converter, but then again ~> maybe not. Anyone have any experience with this code and what we ~> should check next. ~> ~> Thanks in advance, ~> ~> Norm ~ ~ This code will ususally turn out to be a failed catalytic converter. IIRC, there was ~an emissions recall to replace the catalysts on many V-6 Contours. Have your local ~dealer check OASIS to see if the recall is still in effect and if your car qualifies.

Hmmm, thank you for this information, I will follow up on it.

Thanks again.

Norm