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I have 2 error codes P0420 and P0430 which are catalyst or O2 sensor problems. Some threads have said that replacing all 4 sensors will solve the problem or at least start with upstream one. But my mechanic said that usually it means broken catalyst anyway like no point in changing just sensors. So what are your thoughts on that? As I see many have resolved the issue with just changing the sensor.
Also, when I clear the code, it reapear after approx 5-6 days. So any suggestions?
Hi Gert,
I had your problem on my 08 Super V8.
I bought a pair of Oxygen Sensor Extender 90 degree fittings from AliExpress.
They solved the problem and cost less than $20.
I had the P0430 on my car, and it also reappeared every time I cleared it after a few days.
My first try was the cheaper possibility, by replacing all four of the sensors, even though I only had the one eror code for bank 2.
As this did not solve my problem, I removed the exhaust system and found that the left hand catalytic converter was empty! Someone had opened it and had removed the inetrior! I bought a new one and since then I had no issues anymore.
What I would do in your place is to remove the whole exhaust system, including the catalysts, and look how the interior of the catalysts looks like with an endoscope camera. It could be a good starting point to decide whether the catalysts really need replacing. Removing the exhaust system is not a big deal.
I had the P0430 on my car, and it also reappeared every time I cleared it after a few days.
My first try was the cheaper possibility, by replacing all four of the sensors, even though I only had the one eror code for bank 2.
As this did not solve my problem, I removed the exhaust system and found that the left hand catalytic converter was empty! Someone had opened it and had removed the inetrior! I bought a new one and since then I had no issues anymore.
What I would do in your place is to remove the whole exhaust system, including the catalysts, and look how the interior of the catalysts looks like with an endoscope camera. It could be a good starting point to decide whether the catalysts really need replacing. Removing the exhaust system is not a big deal.
Good luck!
Best regards,
Thomas
Hi Thomas,
It must be wonderful to be in Europe and have access to affordable parts. Here in NZ, even sensors are hundreds of dollars, and catalysts are thousands, if you can get them. My $20 spacers have worked well for the past four years.
I am happy for you that the spacers solved the problem, I did not even know something like this exists... learnig really is a continous process
Regarding availability andprices of spares, yes, all in all I assume that the situation might be bettter here in Europe, although it is deteriorating, as well. The sensors were app. 250 EUR back in 2019, I don't know the price now, and the catalyst was 1,200 EUR in 2021, and now you have to pay around 2,000 EUR, if can get one.
I, too, already had to source parts from all over the world, and since the Brexit, the parts from UK have gotten more expensive by around 30%.
But that's the challenge of keeping a special car on the road.
Been getting that way here as well.
Happened with my 84 & 87 GL1200's.
Many NOS parts have been gone for decades.
Used parts are at a premium price, if you can find them.
The 84 Ignition parts are especially scarce.
O2 extenders wouldn't work some places such as UK - anywhere that measures using a probe in the exhaust will detect the cheating.
The P0420 and P0430 codes are from the downstream sensors, and they provide feedback on catalyst efficiency. Errors in the upstream sensors that are used to control the injection will be detectable, but errors in the downstream sensors may not affect the exhaust. Given the price difference, I think it would be worth a try. There is currently no emission testing in NZ, and inspection does not involve the OBDII port.
We may have a better posssibility to source parts, and maybe even at better prices, but, unlike you, we have very strict emission testing, including involving the OBDII port, so the spacers would already be rejected at the visual inspection. Furthermore, if the tester is being really strict, he could argue that the car is not road legal anymore because it has been manipulated and could forcibly stop the usage of the car...
So, I have to spend the money needed to fix the car according to specification.
Upstream o2 sensor, bank one, on 2003 xj8 shorted . Used one from spare car. Here's a picture . The inner orange seal was wrecked and fell apart some fell down on my safety glasses.
since I changed it have more power and more response.
O2 or catalyst change?
