2007 - IS250 - Check VSC

[baviaannl]

Was driving this moring when Check VSC appeared on the display, first thought was confusion, car is running fantastic with no loss of power, bad starts ot anything else worth mentioning.  I turned back home half expecting something to go wrong although it didn't, drove like a dream.

 

Got home, linked it up to the diag OBD reader, only a single code has been found:-

P0420$07E8

 

No associated codes exist!  Quick Google and found this:-

P0420 Causes

A comprehensive list of other issues that could cause the ECU to store a P0420 code is as follows:

• Muffler damage or leaks
• Exhaust manifold damage or leaks
• Exhaust pipe trouble or leaks
• An engine misfire or skip
• Oil leaking into the catalytic converter causing contamination
• Defective engine coolant temperature sensor
• Defective front or rear o2 sensors
• Damaged o2 sensor wiring or connections
• Fuel injector leak
• Higher than normal fuel pressure

First thing that caught my attention was the exhaust possibilities.  I know my exhaust is a POS!  I've had the same silencer fallen off twice is 12 months and had it welded up, the last time it was done, the guy didn't think it was going tolast much longer!

 

I don't want to throw money at the exhaust IF it's something else.  Could someone recommend any test's I can carry out to narrow it down a little here?

 

Thanks in advance

[ColinBarber]

4 main reasons why this code gets triggered.

1. Front O2 sensors aren't working as they should which triggers the rear sensor
2. Air leak in the front exhaust/manifold
3. The cats actually are below a good working threshold
4. The rear sensor is no longer in calibration and detecting a problem when there isn't one.

I've listed in order of likelihood. Many people do number 4 first and it nearly never fixes the issue.

If you have an OBD tool, not just a reader, look at the fuel trims to see if they look ok.

[baviaannl]

26 minutes ago, ColinBarber said:

4 main reasons why this code gets triggered.

1. Front O2 sensors aren't working as they should which triggers the rear sensor
2. Air leak in the front exhaust/manifold
3. The cats actually are below a good working threshold
4. The rear sensor is no longer in calibration and detecting a problem when there isn't one.

I've listed in order of likelihood. Many people do number 4 first and it nearly never fixes the issue.

If you have an OBD tool, not just a reader, look at the fuel trims to see if they look ok.

Thanks Colin, when my silencer fell off, I remember there was a wire connected, I'm guessing this was an 02 sensor?  I remember as I was fighting to disconnect it as I had traffic building up behind me with the exhaust hanging!  I've read that IF performance plummets without these connected, it's a sure sign of of a cat converter going bad...  When they were disconnected on my car, the performance was terrible, really sluggish!

 

My OBD reader did actually say after the P0420$07E8 code :- Catalyst system efficiency below threshold bank 1

 

Thanks

[ColinBarber]

17 minutes ago, baviaannl said:

My ODB reader did actually say after the P0420$07E8 code :- Catalyst system efficiency below threshold bank 1

That is the official description of P0420, but it can be triggered by multiple problems which the ECU or OBD tool cannot determine.

[baviaannl]

20 minutes ago, ColinBarber said:

That is the official description of P0420, but it can be triggered by multiple problems which the ECU or OBD tool cannot determine.

These are my fuel trim readings, not sure what I'm looking at though tbh, anything obvious stand out here?

 

https://linksharing.samsungcloud.com/wrGqa5NF4DRn

[Mr Vlad]

Hi Lee. Funny I've just seen this thread. Why funny? Well that Check VSC came up on my display coincidentally whilst I went over a sleeping police man across the road at an asda. Also at the same time my dash cam stopped working. I googled it when it was safe to pull over on how to clear it. When i got home I took the negative lead Off the Battery for 15 seconds. Re attached and the fault display disappeared. 

I checked then the fuse connection on my hard wired dash cam (a nextbase 322gw). All fuses and connections were fine. Connected the dadh cam to my laptop and no joy. I had to reset the dash cam now all is well. 

I can only assume that whilst going over the sleeping policeman slowly mind something must have dislodged momentarily but enough to stun the dash cam and in turn weirdly the VSC pop up. 

Hope if you disconnect the neg lead from the Battery for 15 seconds all will be well.

[baviaannl]

16 minutes ago, Mr Vlad said:

Hi Lee. Funny I've just seen this thread. Why funny? Well that Check VSC came up on my display coincidentally whilst I went over a sleeping police man across the road at an asda. Also at the same time my dash cam stopped working. I googled it when it was safe to pull over on how to clear it. When i got home I took the negative lead Off the battery for 15 seconds. Re attached and the fault display disappeared. 

I checked then the fuse connection on my hard wired dash cam (a nextbase 322gw). All fuses and connections were fine. Connected the dadh cam to my laptop and no joy. I had to reset the dash cam now all is well. 

I can only assume that whilst going over the sleeping policeman slowly mind something must have dislodged momentarily but enough to stun the dash cam and in turn weirdly the VSC pop up. 

Hope if you disconnect the neg lead from the battery for 15 seconds all will be well.

Hi Vlad

 

I just did the same, disconnected for a few minutes and the Check VSC has also disapeared.   I have a journey this evening so I'll see if the error remains clear or comes back.

 

Mine first appeared on the motorway this morning, prior to that, I'd just filled the tank with petrol so not sure what could have caused it!

 

Thanks for the tip though, lets hope things are good now 🙂

 

[ColinBarber]

P0420 will come and go intermittently, especially at first, as they rely on certain conditions being met which aren't always present.

Your long term trims seem a little high, but on both banks, so I'd check there aren't any vacuum leaks and clean the MAF sensor but that isn't the main reason for a P0420 otherwise you would have a P0430 too. I'd definitely get the exhaust checked for leaks, from the manifold gasket on the engine through to where the pipes join into one.

[bobmc]

On 8/31/2020 at 3:59 PM, baviaannl said:

Mine first appeared on the motorway this morning, prior to that, I'd just filled the tank with petrol so not sure what could have caused it!

 

 

I've had this when I didn't re-fit the fuel filler cap properly, hence a leak was introduced - will cost you nothing to check.