Kia Sportage 2.0 16v G4GC 2007 - Emission failure, code P0133 Bank 1 sensor 1 slow response - Fixed
Posted by Alan Potter on January 10, 2017, 2:17 pm
Year of Manufacture *: 2007 Engine Size and Code *: 2ltr 16v G4GC ( Optional ) Scanner Used: Snap-on, carman scan, autodiagnos. ( Optional) Fault Codes: P0133 Bank 1 sensor 1 slow response rate
Hi. This Kia i have been told failed its mot this time last year on the emissions The mil had been on for a few weeks before the test. The garage replaced the front sensor cleared the codes and the car then passed. However the light came back on after two days. They then replaced it again twice the first two replacements were aftermarket but then both front and rear were replaced with gen kia. but they still kept getting the light two days after each replacement. They then told the customer they could do no more. the customer now had an mot so ignored the light all year until the next mot.
It has now of course failed again at a different garage. and has now been given to me to check. I don't know what the codes were last year but likely the same. P0133 b1s1 slow response. The fail is on co at fast idle at 0.5 Lambda is a pass. although there is a slight leak in the back box that can give a lambda fail on my gas bench but rag up the pipe with the probe proves the leak is only at the back box.
The fail on co at only 0.5 and a pass on lambda would to me point to a failed cat. But for the lambda sensor code. this car has a manifold cat and an under floor cat 1500 quid for genuine ones.
Now what i have done so far.
The car drives very well. It is in closed loop and the fuel trim is short term and long term always plus or minus 2-3. this is the case at idle and cruse. also checked on the motorway. front sensor switching on graphing scan tool. but rear sensor switching also not as much as front. In EOBD mode 5 long before the mil comes back on the weak/rich rise and fall times are a pass but the time it lingers rich or weak is a fail, limit is .6ms. The sensor is taking .9ms.
On the pico, front and rear sensors, rear is switching at almost same rate as front. The front is hanging high/rich three times longer than low/weak. The sensors are both basic 4 wire. I have confirmed the sensors are not pluged in back to front. The front sensor heater is getting a feed and switched neg and has the same resistance as the rear. I have been testing for leaks in intake and exhaust. None found also tried unplugging maf and it did not make any difference.
My main question is if the fuel trim is spot on why would the sensor hang rich longer than weak. i understand it being in closed loop if there are enough cross counts but if its at 0.9v why would the ecu take longer to say go weak than it does to say go rich. Also i understand as the sensor heats up it should speed up. and at higher rpm it should increase in frequency however this appears to not speed up and may even be slower.
Also the freeze frame when the code sets shows closed loop, fuel trim short and long good and engine speed 2800 rpm, 80deg c
Sorry for the long post. Any advice would be great thanks Alan
Re: Kia Sportage
Posted by Tony Ludford on January 11, 2017, 7:10 am, in reply to "Kia Sportage" Tony Ludford
Front Cat' breaks up, debris then get forced into secondary Cat' causing that to fail. Too expensive to repair, people move the car on.
Rear sensor is used for fuel trim, if the Cats are missing, the faster switching is messing with the fuel trims, logging the code.
Needs BOTH cats, as one will pass MOT but die quickly, causing light to return.
Re: Kia Sportage
Posted by alan potter on January 11, 2017, 11:27 am, in reply to "Re: Kia Sportage"
Hi Thanks for replying, have you seen this actual fault on one of these kia engines, sounds like you have seen it often even. I have now pulled the front sensor and looked down on the cat from the top with a borescope and it looks OK. Ill have another look at fuel trims. I think i only saw bank 1 fuel trim and it looked good at all engine speeds I know some vehicles use the post cat sensor for further fueling corrections. The rear sensor is just below the manifold cat then after the flexi there is what kia are telling me is another cat. it does look like one but why would it be after the rear sensor. There are after market cats available still 500 quid for both though.
Re: Kia Sportage
Posted by Tony Ludford on January 11, 2017, 1:18 pm, in reply to "Re: Kia Sportage" Tony Ludford
Yeah I've seen a couple of these. If the second sensor is mimicking the first, the manifold cat is shot. Take the front flexible pipe off (good luck) and check the lower portion of the cat, it's in 2 parts, not 1 solid monolith.
These will pass the mot with only the manifold cat, but only if the engine is well warmed.
Re: Kia Sportage
Posted by alan potter on January 11, 2017, 4:15 pm, in reply to "Re: Kia Sportage" Alan Potter
Tony thanks for that ill have a good look inside the cat.
As i said if it was not for the lambda sensor code I would be changing the cat based on the co reading wich is exactly as a normal car with no cat.And sensor 1 fuel trim good in closed loop and all other gas bench values a pass and lambda 1 confirmed on gas bench. Its the slow switching lambda and the code thats got me nervous of cat replacement. would be an expensive mistake if new cat made no differance . and yes all exhaust bolts are shot and will need cutting off. ill look in the post cat sensor hole back up at the manafold first
Re: Kia Sportage
Posted by Christy Doyle on January 12, 2017, 6:59 pm, in reply to "Re: Kia Sportage" Christy Doyle
Can you check temperature difference between inlet and outlet on both cats at operating temperature which would save removing the cats to check,
Re: Kia Sportage
Posted by Shane gray on January 12, 2017, 8:29 pm, in reply to "Re: Kia Sportage"
Hi Alan, Like Tony said if the rear sensor is same as front then it's the cats, the rear sensor should hold around 0.4 v when hot and at idle for an efficient cat.
Hi I Know this was more than a year ago but i did fix it and the car is still good more than a year later so i thought id post the fix as i should have at the time.
The mode 5 data in obd was part of the answer. The transition speed of the front sensor rich /lean and lean/rich was within tolerance but when it was rich it would linger there too long. I had previously disconnected the maf sensor and noted it made no difference to the lambda sensor on the scope. However later i tried that again but i left it running like that for a while and gradually the lambda switching improved. In much the same way short and long term fuel trim values slowly correct them selfs if you can't reset adaptations. As soon as i plugged the maf back in. It slowly returned to the hanging high thing again.
I would not normal wast my time tiring to clean a maf sensor but as i still was not convinced i gave it a try and it worked. Now we had a correctly switching lambda. and after a long test drive no lambda fault codes. However the Cat was still not working. so we replaced it and once the old one was off although it had looked intact from both ends with a camera in the lambda holes when given a shake it rattled. Again I'm very wary of after-market cats but one of the better makes did have one listed. We only replaced the front manifold cat and the vehicle passed it test.
I warned the customer about possible short life expectancy of after-market cats. They were happy to try as they would not be able to afford the dealer part.
So two faults. possibly one leading to the other A mixture fault upsetting the lambda but oddly not showing as fuel trim in the normal way that I'm used to. Caused by a dirty air flow meter and resulting in long term cat damage
on January 11, 2017, 7:10 am, in reply to "