Oh oh, check VSC!

The-Acre · February 3, 2018

In another post I mentioned the check VSC appearing in the first few days and the dealer agreeing to pay for the repair. My local Jaguar specialist read the fault as 02 sensor bank one sensor two. An OE part was fitted, I did about 50 miles and all was good, until this morning when it came back on. Any thoughts on this? The car runs fine.

Upex · February 3, 2018

Hum, interesting getting jaguar looking at you Lexus.

I get check vsc when Battery not up to proper charge (I'm on original Battery still from 2006 😁) as not had time to order a new one. Try giving it some more 12v juice (I jump from a spare battery) as can be done in 30s and don't need to pay anything.

Other than that, not a clue, as don't see how an 02 sensor would cause it?

bobmc · February 3, 2018

Do you have an OBD reader? If not, they're quite cheap and very handy to have in situations like this. Either one that links to your smartphone to display results (between £10 and £20) or one with a built in display (£20 to £30) - they're generic so work on all cars.

If you can also get hold of the adapter cable and the techstream software as well then this is what the Lexus tech's use. hint - do a search for techstream on the forum

Without knowing if the same code has been logged or if it's a new code, its just guesswork

Malachy · February 3, 2018

I get this on mine the odd time especially after rain. I replaced the fuel filler cap as this got rid of it as it was coming on all the time. It comes on now every 6 months so I just disconnect the Battery for 5 mins and that clears it.

My Lexus garage diagnosed it as two faulty O2 sensors..

cruisermark · February 3, 2018

43 minutes ago, Malachy said:

I get this on mine the odd time especially after rain. I replaced the fuel filler cap as this got rid of it as it was coming on all the time. It comes on now every 6 months so I just disconnect the battery for 5 mins and that clears it.

My Lexus garage diagnosed it as two faulty O2 sensors..

Is this on a 430? - I have this problem aswell and the garage has read the code as oxygen sensor - I have tried the petrol cap gasket by wonder wether I should try replacing the whole cap? The garage did say they emissions are within the limits.

The-Acre · February 3, 2018

Thanks for the replies. Mark, it's on my GS300. The Jag guy is a friend and has excellent diagnostic equipment because he works on many different cars. I do have my own OBD11 reader, I'll try that in the morning to see what that shows. The fuel cap thing features a lot on US sites so I'll give that a go as well, especially as it happened the day after I filled up.

Malachy · February 3, 2018

49 minutes ago, cruisermark said:

Is this on a 430? - I have this problem aswell and the garage has read the code as oxygen sensor - I have tried the petrol cap gasket by wonder wether I should try replacing the whole cap? The garage did say they emissions are within the limits.

No mine is a 300! My emmisions were perfect when the light was on so that LED me to believe the sensors were ok. I ordered the cap from my Toyota dealer they are cheap..

ColinBarber · February 3, 2018

Downstream O2 sensors are rarely the fault, even if the code states it is. Typically it is a problem with the upstream sensor. Unless it was a problem with the downstream heater in which case the error code is typically accurate.

Do you know the actual error code that was produced?

The-Acre · February 3, 2018

1 hour ago, ColinBarber said:

Downstream O2 sensors are rarely the fault, even if the code states it is. Typically it is a problem with the upstream sensor. Unless it was a problem with the downstream heater in which case the error code is typically accurate.

Do you know the actual error code that was produced?

I can't remember without asking him, I seem to recall it was something like P1603

SpeedyGee · February 4, 2018

13 hours ago, The-Acre said:

In another post I mentioned the check VSC appearing in the first few days and the dealer agreeing to pay for the repair. My local Jaguar specialist read the fault as 02 sensor bank one sensor two. An OE part was fitted, I did about 50 miles and all was good, until this morning when it came back on. Any thoughts on this? The car runs fine.

After fitting the new part, the codes will have been cleared.

It may be that the clearing of the codes was what gave you 50 miles of no check VSC showing as opposed to being due to the new part.

The-Acre · February 4, 2018

1 hour ago, SpeedyGee said:

After fitting the new part, the codes will have been cleared.

It may be that the clearing of the codes was what gave you 50 miles of no check VSC showing as opposed to being due to the new part.

That's what I'm thinking, in which case why does it come back on. I saw the new part and I was there for the fitting.

SpeedyGee · February 4, 2018

Get the code rechecked and see if it's the same code or a different one this time.

SpeedyGee · February 4, 2018

What condition is the exhaust system in? Any signs of any leaks? Especially before the O2 sensor.

Would be worth monitoring the fuel trim readings of both banks, see if that gives a clue.

The-Acre · February 4, 2018

4 hours ago, SpeedyGee said:

What condition is the exhaust system in? Any signs of any leaks? Especially before the O2 sensor.

Would be worth monitoring the fuel trim readings of both banks, see if that gives a clue.

As far as I'm aware the exhaust system is good. The last main dealer service was 2k ago and I would hope any exhaust problem would have been identified! The VSC check was on again this morning, then an hour later it wasn't. I scanned it and it came back with PO138 02 sensor bank 1 sensor 2 which is the one replaced. The mystery continues.

bobmc · February 4, 2018

I don't claim any expertise here but my *limited* understanding is that sensor 2 is downstream and that errors on the downstream o2 sensors can indicate problems with the catalytic convertor.

If the original sensor was not faulty and was reporting a lack of o2 in the exhaust gases then a new sensor will report the same condition. Simplest check now would seem to be to swap bank 1 and bank 2 sensors to see if fault moves.

SpeedyGee · February 4, 2018

Yes, that's right Bob, sensor 2 is post cat and that's a good suggestion, it is worth swapping the sensors around.

Cat's don't go easily though, hence I was wondering about a leak.

ColinBarber · February 4, 2018

If you have replaced the sensor then it rules it out and the heater circuit. Unlikely to be a cabling fault so replacing the upstream sensor is the next thing to try. I don't think it is the cat, that would produce an efficiency error code.

The-Acre · February 4, 2018

It is the upstream sensor that's been replaced. Bank 1 sensor 2 (the drivers side) The faulty sensor was also verified by erasing the code and then disconnecting the sensor and diagnosing again if that makes sense.

Chasdad · February 4, 2018

i know its not the same but my 3.5 elgrand came up with the fault. 02 sensor .not vsc but just engine light. i cleared it used it for a bit .was fine until i left it for a few weeks unused.

started it and came on. i cleared it again and its been off. I'm wondering if its Battery related too as I'm sure i had the vsc light come on when my 5 series Battery went flat

ColinBarber · February 4, 2018

2 hours ago, The-Acre said:

It is the upstream sensor that's been replaced. Bank 1 sensor 2 (the drivers side) The faulty sensor was also verified by erasing the code and then disconnecting the sensor and diagnosing again if that makes sense.

Bank 1 sensor 2 is the downstream sensor. Bank 1 sensor 1 is upstream.

messi · February 4, 2018

Sometimes it could be down to the vvt solenoid needing to be replaced.

The-Acre · February 5, 2018

8 hours ago, ColinBarber said:

Bank 1 sensor 2 is the downstream sensor. Bank 1 sensor 1 is upstream.

That would explain a lot! I did contact my local Toyota dealer who sometimes get me Lexus parts and they did say it was the upstream sensor that was bank one. Now I'm really confused!!

SpeedyGee · February 5, 2018

Bank 1 and Bank 2 refer to the banks of cylinders on the V. So the V configuration of the engine has 3 cylinders on each bank.

Each Bank has 2 O2 sensors, primary or upstream called sensor 1 and secondary or downstream called sensor 2.

The-Acre · February 5, 2018

35 minutes ago, SpeedyGee said:

Bank 1 and Bank 2 refer to the banks of cylinders on the V. So the V configuration of the engine has 3 cylinders on each bank.

Each Bank has 2 O2 sensors, primary or upstream called sensor 1 and secondary or downstream called sensor 2.

So when the code indicates bank 1 sensor 2 is that referring to the drivers side? In which case the wrong sensor has been replaced which explains a lot. it also explains Roberts questioning about a Jaguar specialist looking at it!