Hi,
I have a 2001 Montero Sport with 191xxx miles on it. I recently took the montero in to have it's annual state inspection and 2 codes are showing P0421 and P0403.
I got a description of the codes that popped up and I am curious. I have never once had a Check Engine Light/Check Engine Soon light come on. The inspector checked and the light works, but has never come on.

The P0403 Code is an EGR Valve malfunction. Is this hard to Clean and or Replace?

The P0421 says Warm Up Catalyst Efficiency Below Threshold. Of course the Tech/Salesman tells me I need a New Cat Converter, to where another says to replace the Rear O2 Sensor.


Any help would be appreciated. I can't justify shelling out $1,000 + on a vehicle I paid $2800 for.


Thank You!

T

 

Mine has shown this for several years. I simple ignored. I read in several post that it is either the 02 sensors or the cat converter. To be sure, you want to have a qualified technician tell you exactly which is wrong. If its the cat converter, they suggested you change the 02 sensor as well. If it is 02 sensor, you can get 02 sensor for less than $100.00. You need to shop around. Another thing about vehicles, no matter how much you paid for it , things are gonna go bad, so be ready to repair it or get you a new car. Yoy can shop around Online for the cheapest possible parts. Avoid eBay for parts as much as possible. It is a waste of time trying to match the right part for your vehicle unless you call sellers to confirm with your VIN number. Good luck

 

[QUOTE=TDM556;303700]Hi,
I have a 2001 Montero Sport with 191xxx miles on it. I recently took the montero in to have it's annual state inspection and 2 codes are showing P0421 and P0403.
I got a description of the codes that popped up and I am curious. I have never once had a Check Engine Light/Check Engine Soon light come on. The inspector checked and the light works, but has never come on.

The P0403 Code is an EGR Valve malfunction. Is this hard to Clean and or Replace?

The P0421 says Warm Up Catalyst Efficiency Below Threshold. Of course the Tech/Salesman tells me I need a New Cat Converter, to where another says to replace the Rear O2 Sensor.


Any help would be appreciated. I can't justify shelling out $1,000 + on a vehicle I paid $2800 for.


I have these same 2 codes coming up on mine. I took the egr valve off and cleaned it. New rear 02 sensor only because i changed the cat. So I highly doubt either of those are your problem. Im going to change my egr valve silenoid. I put a multi meter on it the wiring harness is hot. I don't know how to check silenoid but I'm betting that's my problem. I also have a bank 1 02 sensor that i will change but I'm going to do solenoid first becauseI'm betting that's my problem or a sensor somewhere related to the egr valve. Once i cleaned it i seen that it is functioning. However on live data it opens and closes correctly but then faults and goes back to closed. So either cleaning it didn'tdo any good or the solenoid isn't registering the egr valve but i do have a check engine light that had egr circulation control circuit pending a couple times then it registered.