Catalyst DTCs P420/P430 w/ VSC issues too
11-01-11, 09:49 PM
#1
Pit Crew
Thread Starter
Catalyst DTCs P420/P430 w/ VSC issues too
Just replaced the alternator. Between the actual job and several battery swaps to stay mobile with an inop alternator, there were many ECM reset cycles. After about 15 drive miles, the check engine light came on, along with annuciators for "VSC TRAC OFF, VSC OFF,", and slippery-vehicle symbol. Read the DTCs with my own OBDII diagnostic tool. Codes P0420/P0430 relating to catalyst below efficiency threshold, bank 1/bank2. I erased the DTCs with the key on. Started the engine (without cycling the key off). The check engine light cleared, but the three VSC-related icons remained. Key off. Restart. Display normal and started the engine. My hopes and thoughts: ECM confusion caused by all the disconnects, and the codes were waiting to show after sufficient drive time. And/or VSC issues indicated as I reaction to my messing with the KDSS. Due to sway bar removal and variations in lifting the front end, the KDSS disconnect solenoid dropped. Does KDSS activation turn off the VSC? I seem to recall something like that. I'm on Double Secret Probation for wheelin' in the wife's GX, so I have not deployed KDSS for it's intended purpose in a while! Anyhow, two seemingly unrelated systems triggering DTCs simultaneously makes me think it's all related to the alternator replacement. Hopefully more driving will not result in code repeats. Any ideas?
11-01-11, 10:08 PM
#2
The Fault would arise because the ECM has detected the change in component, And that is why it give this indications, All you need is to reset the ECM module or shud say Re-Flash calibration thru the interface, so that the New values of the Alternator get stored. Because the alternator values are stored in combination with the ECU and have an internal security built up not to allow to program with any other information, Unless you re-flash it, you will have the error, That I what I have understood.
11-02-11, 05:39 AM
#3
Pit Crew
Thread Starter
The Fault would arise because the ECM has detected the change in component, And that is why it give this indications, All you need is to reset the ECM module or shud say Re-Flash calibration thru the interface, so that the New values of the Alternator get stored. Because the alternator values are stored in combination with the ECU and have an internal security built up not to allow to program with any other information, Unless you re-flash it, you will have the error, That I what I have understood.
11-03-11, 09:18 AM
#4
Lexus Test Driver
I think he means to reset the ecu? I know in the IS350, you can pull the ects 10 amp fuse and Fuel relay1 25 amp fuse under the engine compartment fuse panel, if you dont want to disconnect your battery and lose all kinds of settings.
Im still new to the GX470 as I just bought a 2008 for my wife a few weeks back. I cant WAIT to put a 2 inch lift and some nice mud terrains on it. Lucky for me she's a country girl at heart and doesnt mind it at all.
Im still new to the GX470 as I just bought a 2008 for my wife a few weeks back. I cant WAIT to put a 2 inch lift and some nice mud terrains on it. Lucky for me she's a country girl at heart and doesnt mind it at all.
11-03-11, 08:15 PM
#5
Just replaced the alternator. Between the actual job and several battery swaps to stay mobile with an inop alternator, there were many ECM reset cycles. After about 15 drive miles, the check engine light came on, along with annuciators for "VSC TRAC OFF, VSC OFF,", and slippery-vehicle symbol. Read the DTCs with my own OBDII diagnostic tool. Codes P0420/P0430 relating to catalyst below efficiency threshold, bank 1/bank2. I erased the DTCs with the key on. Started the engine (without cycling the key off). The check engine light cleared, but the three VSC-related icons remained. Key off. Restart. Display normal and started the engine. My hopes and thoughts: ECM confusion caused by all the disconnects, and the codes were waiting to show after sufficient drive time. And/or VSC issues indicated as I reaction to my messing with the KDSS. Due to sway bar removal and variations in lifting the front end, the KDSS disconnect solenoid dropped. Does KDSS activation turn off the VSC? I seem to recall something like that. I'm on Double Secret Probation for wheelin' in the wife's GX, so I have not deployed KDSS for it's intended purpose in a while! Anyhow, two seemingly unrelated systems triggering DTCs simultaneously makes me think it's all related to the alternator replacement. Hopefully more driving will not result in code repeats. Any ideas?
11-03-11, 08:41 PM
#6
None of those codes are related whatsoever to the gas cap, the alternator, etc.
Where to start? Sometimes, on Lexus', when the check engine light is set, and the VSC lights come on, you have to reset them separately... Real good scantools are capable of this, but, if yours isn't, you can follow these directions to reset the VSC / Trac lights:
1-Connect the wire to terminals Tc-CG on the ODBII connector under the dash (or in the engine compartment)
2-Turn ignition switch on
3-Depress the brake pedal 8 or more times within 5 seconds
4-Turn off ignition
5-Remove the wire
Then, you still might have issues with the catalytic converter issues, only way to tell is to simply drive the car...
Where to start? Sometimes, on Lexus', when the check engine light is set, and the VSC lights come on, you have to reset them separately... Real good scantools are capable of this, but, if yours isn't, you can follow these directions to reset the VSC / Trac lights:
1-Connect the wire to terminals Tc-CG on the ODBII connector under the dash (or in the engine compartment)
2-Turn ignition switch on
3-Depress the brake pedal 8 or more times within 5 seconds
4-Turn off ignition
5-Remove the wire
Then, you still might have issues with the catalytic converter issues, only way to tell is to simply drive the car...
11-03-11, 08:47 PM
#7
None of those codes are related whatsoever to the gas cap, the alternator, etc.
Where to start? Sometimes, on Lexus', when the check engine light is set, and the VSC lights come on, you have to reset them separately... Real good scantools are capable of this, but, if yours isn't, you can follow these directions to reset the VSC / Trac lights:
1-Connect the wire to terminals Tc-CG on the ODBII connector under the dash (or in the engine compartment)
2-Turn ignition switch on
3-Depress the brake pedal 8 or more times within 5 seconds
4-Turn off ignition
5-Remove the wire
Then, you still might have issues with the catalytic converter issues, only way to tell is to simply drive the car...
Where to start? Sometimes, on Lexus', when the check engine light is set, and the VSC lights come on, you have to reset them separately... Real good scantools are capable of this, but, if yours isn't, you can follow these directions to reset the VSC / Trac lights:
1-Connect the wire to terminals Tc-CG on the ODBII connector under the dash (or in the engine compartment)
2-Turn ignition switch on
3-Depress the brake pedal 8 or more times within 5 seconds
4-Turn off ignition
5-Remove the wire
Then, you still might have issues with the catalytic converter issues, only way to tell is to simply drive the car...
New gas cap fixed my issue.
Trending Topics
11-03-11, 09:16 PM
#8
The codes that were probably stored for your car were most likely P0442 or P0456, both which indicate a small leak in the evaporative emissions system. The codes in this case are P0420/P0430, which indicate that the catalytic converter is not working at the proper efficiency level. Now, this isn't always correct, as weird voltages and wonky O2 sensor readings can cause these codes to be stored (especially when you see both sides at the same time, as in this case).
So, while a bad gas cap can fix 1 or 2 possible codes, keep an open mind when it comes to things like this, as there are literally hundreds of other codes that could be setting the light as well... I'm not a fan of fixing things that aren't broken, and, whilst companies like Stant that make gas caps would love it if everyone replaced their gas cap straight away when the check engine light came on, I can't justify telling someone to do that unless the diagnostic codes lead me that direction...
Its kinda like saying "my head hurts." Well, there are lots of reasons your head could hurt, and while tylenol may take care of the issue and be a cheap fix, at the same time, you could also be starting to have a serious issue like a tumor, in which case, taking tylenol is just a waste of time...
11-03-11, 09:19 PM
#9
It could be the oxygen sensors also, see this:
http://www.tundrasolutions.com/forum...r-from-toyota/
http://www.tundrasolutions.com/forum...r-from-toyota/
11-03-11, 09:23 PM
#10
It could be the oxygen sensors also, see this:
http://www.tundrasolutions.com/forum...r-from-toyota/
http://www.tundrasolutions.com/forum...r-from-toyota/
11-03-11, 10:28 PM
#11
Pit Crew
Thread Starter
None of those codes are related whatsoever to the gas cap, the alternator, etc.
Where to start? Sometimes, on Lexus', when the check engine light is set, and the VSC lights come on, you have to reset them separately... Real good scantools are capable of this, but, if yours isn't, you can follow these directions to reset the VSC / Trac lights:
1-Connect the wire to terminals Tc-CG on the ODBII connector under the dash (or in the engine compartment)
Where to start? Sometimes, on Lexus', when the check engine light is set, and the VSC lights come on, you have to reset them separately... Real good scantools are capable of this, but, if yours isn't, you can follow these directions to reset the VSC / Trac lights:
1-Connect the wire to terminals Tc-CG on the ODBII connector under the dash (or in the engine compartment)
Update - To clarify, I actuallly had four codes: P0420, P0430, one each of bank one, one each for bank 2. After the last post I accomplished one more ECU rest simply due to reinstalling proper battery, in lieu of a temporary that was swapped when alternater malfuntion was apparent. VSC/Check Engine light came on again after some driving. One more OBDII scan - same codes, one reset. Drive again, repeat. Mitsuguy, my tool is only cabable of resetting all codes, I think. But I will double check. I will look at the gas cap. Coincidently, I refueled today, so the tank went from about 1/8 to full, and the cap was reseated with no special emphasis, just turn to click. Codes appeared after fueling. I must ask more about your "step 1" in the quote. TC and CG represent two individual OBD terminals, and the procedure is to place a jumper between them before performing the additional steps? If so, how do I identify TC and CG? I only know how to plug and unplug the scal tool form the OBDII port. Thanks!
11-04-11, 03:34 AM
#13
Can you do a check on the Hose and the Tube which is located on the below the fuel tank. And check if they are loosely connected or disconnected.. Sometimes they have Airleak also which are connected to the Charcoal Canister. I had mine a year back , Just tightened and they dissapeared. Do this
1.Shut the Engine Off
2. Go Below the Rear of the car ( right under the fuel tank and you will see a hose from the Fuel tank to the Charcoal Cannisted gettting Connected.
3. Either Side the Clamps need to be tightened.
4. Disconnect the Battery for 5 minutes ( Only (-) terminal
5 Goto the Engine Bay Remove the EFI Relay & EFI Fuse 2 in the Main Fuse Box The location is mentioned on the underside of the Fuse Cover. Wait for 3 Minutes.
5.Reconnect the battery terminals And start the Car. And you should see the warning message dissappear.
1.Shut the Engine Off
2. Go Below the Rear of the car ( right under the fuel tank and you will see a hose from the Fuel tank to the Charcoal Cannisted gettting Connected.
3. Either Side the Clamps need to be tightened.
4. Disconnect the Battery for 5 minutes ( Only (-) terminal
5 Goto the Engine Bay Remove the EFI Relay & EFI Fuse 2 in the Main Fuse Box The location is mentioned on the underside of the Fuse Cover. Wait for 3 Minutes.
5.Reconnect the battery terminals And start the Car. And you should see the warning message dissappear.
11-04-11, 05:40 AM
#14
Can you do a check on the Hose and the Tube which is located on the below the fuel tank. And check if they are loosely connected or disconnected.. Sometimes they have Airleak also which are connected to the Charcoal Canister. I had mine a year back , Just tightened and they dissapeared. Do this
1.Shut the Engine Off
2. Go Below the Rear of the car ( right under the fuel tank and you will see a hose from the Fuel tank to the Charcoal Cannisted gettting Connected.
3. Either Side the Clamps need to be tightened.
4. Disconnect the Battery for 5 minutes ( Only (-) terminal
5 Goto the Engine Bay Remove the EFI Relay & EFI Fuse 2 in the Main Fuse Box The location is mentioned on the underside of the Fuse Cover. Wait for 3 Minutes.
5.Reconnect the battery terminals And start the Car. And you should see the warning message dissappear.
1.Shut the Engine Off
2. Go Below the Rear of the car ( right under the fuel tank and you will see a hose from the Fuel tank to the Charcoal Cannisted gettting Connected.
3. Either Side the Clamps need to be tightened.
4. Disconnect the Battery for 5 minutes ( Only (-) terminal
5 Goto the Engine Bay Remove the EFI Relay & EFI Fuse 2 in the Main Fuse Box The location is mentioned on the underside of the Fuse Cover. Wait for 3 Minutes.
5.Reconnect the battery terminals And start the Car. And you should see the warning message dissappear.
Guys, we can't be throwing out guesses to fix the problem here.
Follow the codes, they will not lead you astray!!!
Zippin - you HAVE to drive for some time, a day or two, without clearing codes... Then, once the light comes on and you still drive some time, please write down all the codes in the system... A new alternator will be highly unlikely to set codes, so long as it working properly - if it is not putting out the correct voltage, it can cause some sensors to not behave correctly...
The TC and CG should be labeled underneath the dash, if not, you should be able to find a diagnostic connector in the engine compartment that is easier to get to and most likely labeled better... If you do use the one in the engine compartment (keep in mind, I'm not 100% sure all Lexus have them, but every Lexus I've owned has had one, and the GS in my driveway right now doesn't have the factory wiring due to a GTE swap, so I'm not sure if it ever had one or not), anyways, if you do use the one in the engine compartment, make sure to unplug your diagnostic scanner from underneath the dash...
Chances are, if your scantool is a cheapie (less than $1000), it is not able to read and reset any of the secondary systems, only the engine related systems...