Hello guys. I took the car out for the second tome on a 160km journey yesterday. I just noticed during the journey that the check engine light came on. This morning I did the self diagnostic scan and obtain P0420 which is catalytic code, bank 1. What could be wrong with the engine please?


I also noticed that the CVT gear was kind of harder to engage to "R" and "P". Could this also be a sign of some faults that require attention? Your kind comments are appreciated.

Run a comprehensive scan

mayor2013: Run a comprehensive scan

You didnt make any comment on the error code obtained. Lets start from there.

The trans issue could be a by product of the CEL, perhaps the car is going into some sort of safe mode.

Regarding the code, if it were my car, I would get underneath it (safety first blah blah blah) and inspect the wirings of the o2 sensors, check for exhaust leaks (if you keep your car clean then you'll be able to see the tell tale signs of soot, etc).

I'll then move on to checking the o2 sensors (either with a know good one or electronically testing the unit). The last thing I would do is to remove the cat itself form the car to I can do a visual and physical inspection to determine if it needs replacing.

Did you clear the code and it came back?

For the code check for a leaking exaust, if there's are no leaks rest code and check if it comes back.

For the hard shifting avoid resting the car on park, pull the parking brakes before shifting to park.

If that doesn't work check the transmission oil, if that is fine check the shifter cable, if that is not stiff there's nothing else that is servicable just manage her like that.

CityNG: The trans issue could be a by product of the CEL, perhaps the car is going into some sort of safe mode.

Regarding the code, if it were my car, I would get underneath it (safety first blah blah blah) and inspect the wirings of the o2 sensors, check for exhaust leaks (if you keep your car clean then you'll be able to see the tell tale signs of soot, etc).

I'll then move on to checking the o2 sensors (either with a know good one or electronically testing the unit). The last thing I would do is to remove the cat itself form the car to I can do a visual and physical inspection to determine if it needs replacing.

Did you clear the code and it came back?

Thanks for your response. I didnt clear the code. I have once checked the exhaust area and saw a wire left on its own without any connection. Perhaps that was the O2 sensor connection. Maybe the thieves we call mechanics and panel beater have done the stealing as usual.

GAZZUZZ: For the code check for a leaking exaust, if there's are no leaks rest code and check if it comes back.

For the hard shifting avoid resting the car on park, pull the parking brakes before shifting to park.

If that doesn't work check the transmission oil, if that is fine check the shifter cable, if that is not stiff there's nothing else that is servicable just manage her like that.

Thanks man. I recently replaced the tranny oil with recommended NS1. Now I like to check the shifter cable but i dont know where it is and how to identify it. . Can you direct me?

pragmatistm: Thanks for your response. I didnt clear the code. I have once checked the exhaust area and saw a wire left on its own without any connection. Perhaps that was the O2 sensor connection. Maybe the thieves we call mechanics and panel beater have done the stealing as usual.

Yeah I've heard horror stories about the shade tree mechanics in Nigeria.

1) Write down the code number so you don't forget, then clear it.

2) If/when CEL comes back, scan it again and compare the code, if it's the same then there really is an issue that needs to be solved.

3) There should not be any loose wire on a modern car down there so either the mechanic removed the o2 sensor, or the wire was loose and got snagged on our cursed roads.

You need to make sure that you have your o2 sensor plugged in. There may be two of them, a pre cat and an after cat. Now if you decide to not run a cat then there are dummy o2 sensors that you can buy and install that will trick the ECU into thinking that there's a working o2 sensor in the system. But you can't have an open loop in the system without triggering a CEL.

pragmatistm: Thanks man. I recently replaced the tranny oil with recommended NS1. Now I like to check the shifter cable but i dont know where it is and how to identify it. . Can you direct me?

I had a rethink I doubt the problem is from your shifter cable, but if you want to know where it is have somone shift the leaver while you look inside the engine bay probably on top transmission you will see the cable moving. (Since the other gears are shifting fine, D,N,L then cable should be fine.)

GAZZUZZ:

I had a rethink I doubt the problem is from your shifter cable, but if you want to know where it is have somone shift the leaver while you look inside the engine bay probably on top transmission you will see the cable moving. (Since the other gears are shifting fine, D,N,L then cable should be fine.)

Bingo.

CityNG:

Yeah I've heard horror stories about the shade tree mechanics in Nigeria.

1) Write down the code number so you don't forget, then clear it.

2) If/when CEL comes back, scan it again and compare the code, if it's the same then there really is an issue that needs to be solved.

3) There should not be any loose wire on a modern car down there so either the mechanic removed the o2 sensor, or the wire was loose and got snagged on our cursed roads.

You need to make sure that you have your o2 sensor plugged in. There may be two of them, a pre cat and an after cat. Now if you decide to not run a cat then there are dummy o2 sensors that you can buy and install that will trick the ECU into thinking that there's a working o2 sensor in the system. But you can't have an open loop in the system without triggering a CEL.

Thanks a lot. I will have little time tomorrow and do as you have suggested. But please where can I get the dummy O2 sensors in Ogun/ Lagos? Im actually in Ilaro,Ogun state.

GAZZUZZ:

I had a rethink I doubt the problem is from your shifter cable, but if you want to know where it is have somone shift the leaver while you look inside the engine bay probably on top transmission you will see the cable moving. (Since the other gears are shifting fine, D,N,L then cable should be fine.)

Ok. Thanks.

pragmatistm: Thanks a lot. I will have little time tomorrow and do as you have suggested. But please where can I get the dummy O2 sensors in Ogun/ Lagos? Im actually in Ilaro,Ogun state.

I'll let the others advice you as I am not Lagos versed.

I cleared the codes since two days now and the light has not returned.

People, what should I check on the engine? I cleared the code but it returned yesterday. Same 0420 code. Then I noticed since the said 160km journey that the engine makes a deeper sound when revved. I don't know if this is related to the error code.

pragmatistm: People, what should I check on the engine? I cleared the code but it returned yesterday. Same 0420 code. Then I noticed since the said 160km journey that the engine makes a deeper sound when revved. I don't know if this is related to the error code.

Check for a blocked exhaust. Probably your catalyst is so damaged its not allowing air go through freely. Or probably it was stolen and filled with materials that have blocked your exhaust.

pragmatistm: Hello guys. I took the car out for the second tome on a 160km journey yesterday. I just noticed during the journey that the check engine light came on. This morning I did the self diagnostic scan and obtain P0420 which is catalytic code, bank 1. What could be wrong with the engine please?


I also noticed that the CVT gear was kind of harder to engage to "R" and "P". Could this also be a sign of some faults that require attention? Your kind comments are appreciated.

Check the 2 O2 sensors on the vehicle, one is attached immediately after the exhaust manifold at the engine compartment or nearly below the engine, the 2nd is attached close to the exhaust maufler or catalytic converter, it looks more like a plug but its not.

pragmatistm: Hello guys. I took the car out for the second tome on a 160km journey yesterday. I just noticed during the journey that the check engine light came on. This morning I did the self diagnostic scan and obtain P0420 which is catalytic code, bank 1. What could be wrong with the engine please?


I also noticed that the CVT gear was kind of harder to engage to "R" and "P". Could this also be a sign of some faults that require attention? Your kind comments are appreciated.

You can as well test the working of your o2 sensors and see if they are still working, 1 good thing with all these sensors is that they really last very long time, yet they can still get damaged; that's why we have the spare part shop.
Get a digital multimeter from electronic store, with the red wire of the o2 sensor attached to the red of the multimeter and the black wire of the multimeter attached to the metal body of the sensor, put on a gas burner and gradually take the sensor near to the flame, keep it above the flame. the meter should read sharply to about 0.6V to 0.9V (not more than that). This shows your sensor is working fine and running rich mixture.
If approaching the flame and it doesn't show any reading on the meter, definitely your sensor is bad, get it changed immediately, this is very essential to the engines smooth running, modern cars from 1994 I guess have these sensors, the send data to the vehicle's ECU to enable it adjust how much fuel it injects into the system and blah blah blah happening inside the cylinders. so when it goes wrong, the system will definitely be faulty.
NB: to use your multimeter, you have to set the range to the lowest voltage range, some meters have it as 2V as the lowest range.
Hope it helps

chuchutech:
You can as well test the working of your o2 sensors and see if they are still working, 1 good thing with all these sensors is that they really last very long time, yet they can still get damaged; that's why we have the spare part shop.
Get a digital multimeter from electronic store, with the red wire of the o2 sensor attached to the red of the multimeter and the black wire of the multimeter attached to the metal body of the sensor, put on a gas burner and gradually take the sensor near to the flame, keep it above the flame. the meter should read sharply to about 0.6V to 0.9V (not more than that). This shows your sensor is working fine and running rich mixture.
If approaching the flame and it doesn't show any reading on the meter, definitely your sensor is bad, get it changed immediately, this is very essential to the engines smooth running, modern cars from 1994 I guess have these sensors, the send data to the vehicle's ECU to enable it adjust how much fuel it injects into the system and blah blah blah happening inside the cylinders. so when it goes wrong, the system will definitely be faulty.
NB: to use your multimeter, you have to set the range to the lowest voltage range, some meters have it as 2V as the lowest range.
Hope it helps

Thanks a bunch. I should try that and revert to the forum. I'm grateful.

GAZZUZZ:

Check for a blocked exhaust. Probably your catalyst is so damaged its not allowing air go through freely. Or probably it was stolen and filled with materials that have blocked your exhaust.

Thanks. Actually, the catalyst had been stolen and I think the compartment was left empty when we checked last. But as you mentioned, I should check it again.

I have discovered something. P0420 is very generic, and include some different possible fault areas from different scanners. I would prefer to consult my vehicle repair manual, which is more direct. Yes, they all interpret it as 'Catalyst operating efficiency below threshold . bank1", but the details vary.

The scanner gave details: Mechanical condition of engine. Faulty wiring and connection. Faulty exygen sensors.

My repair manual details in order of probability: 1. Front exhaust pipe (with three-way catalytic converter) 2. Gas leakage from exhaust system 3. A/F sensor (bank 1 sensor 1) 4.HO2 sensor (bank 1 sensor 2).

You will agree the repair manual is much more helpful with interpretation.

Kashif: I have discovered something. P0420 is very generic, and include some different possible fault areas from different scanners. I would prefer to consult my vehicle repair manual, which is more direct. Yes, they all interpret it as 'Catalyst operating efficiency below threshold . bank1", but the details vary.

The scanner gave details: Mechanical condition of engine. Faulty wiring and connection. Faulty exygen sensors.

My repair manual details in order of probability: 1. Front exhaust pipe (with three-way catalytic converter) 2. Gas leakage from exhaust system 3. A/F sensor (bank 1 sensor 1) 4.HO2 sensor (bank 1 sensor 2).

You will agree the repair manual is much more helpful with interpretation.

Very informative, I must say. I will have to do a wholistic job to fix the problem.