Hello,

my name is Alexander and I am new to this forum and I would appreciate your help. My car failed the emissions test.

CO was too high at idle (0,97), maximum is 0,30 in germany. At 3000 rpm it was okay. He tested left and right exhaust, also he closed the exhaust with old cloth. Still not good enough. At first I scanned the car with an ELM327 and an android app. It stated that the O2 sensor is faulty. I wasn't so sure about the result so I bought the Autel AP200 Scanner to check again. Its said that this device is good for the X300. Before I checked the OBD I cleaned and put contact-spray on the Papa Indy 61 and Papa Indy 1 (I read about it here).

After that I checked for codes and got the famous P1621 and some other stuff which I erased. I started the engine and checked again for codes after some minutes. No codes. The problem is that the Autel Scanner couldn't read the O2-sensors. :-(

I made some pdf-files about the scans. Please have a look at them and help me. I have no clue what to do next. :-(

Any help is very much appreciated!

Regards,

Alex

 

Assuming the tests were taken when the engine is warmed up, nothing you show is abnormal.

Coolant temp is at 163F (or 73C). Should get hotter.

The LTFT appears to be at 4.7% which isn't terrible. Short term is zero. The unusual thing here, is that the STFT should be changing all the time. The fact that it's steady, at any number is odd.

Throttle is at 12.2% at idle, which is lower than the 12.9% I usually see, but shouldn't be a problem.

When was the last time you replaced the oxygen sensors?

 

Hey,

thanks for your reply. I bought the car two years ago and only drove it about 2500 kilometres since then. The car was tested half a year before I bought it with zero CO emissions at 3110 and 730 RPM, thats whats really odd. I checked for false air with brake cleaner - nothing.
I also checked the headers, I can't see that they are broken.

 

I forgot to say that I changed the air filter and cleaned the MAF and the throttle body with a special spray after I bought it, and I haven't touched the MAF. I also checked the fuses for the O2 sensors (heater) and swapped with it with the one from the wiper fluid pump which looked better yesterday. The fuel consumption is good (about 10-11 litres/100 km).

 

Remember that the oxygen sensors do not last forever. They are meant to be changed. My last ones lasted about 50,000 miles.

The car does not like to give you the OBD codes that would make diagnosing these issues easy!

 

Replacing the O2 sensors would be a good place to start, and cheaper than the Autel scanner!
You say you have checked the headers, have you checked the downpipe flange too? Any leakage above your O2 sensors can let air in which causes a correctly functioning O2 sensor to signal an enrichment of the mixture, which produces the excessive emissions.

 

The Autel scanner was 50.- €, the two sensors are about 100.- € (shipping from UK is 2 weeks) plus garage bill about 150.-€ -200.- € and my garage isn't jaguar experienced. I live in a small town.

I have a Jag but Im not rich. ;-) Yes, I checked all and nothing. Also from what I understand so far is that the trim readings aren't that bad or all wrong. In fact they seem pretty good. In my view that means that the O2 sensors are working or am I wrong? Maybe the cats are defective? Too bad you have to throw parts at the car without knowing whats exactly wrong.

I measured the trims while the car wasn't moving and idling. Is it enough to get above idle or needs the car to be on the "autobahn"? The CO is also measured at idle so it shouldn't matter I guess. :-)

I also got the ELM327 and tested 6 different apps. No logic conclusion possible so far. :-( maybe somebody can light up my mind more please :-) I just want to know my car better, cause I love it.

 

Welcome to the forums Alex,

That low use does not help the emissions problem. Also the engine (and specifically the cats) needs to be thoroughly warmed up before testing. I always take my car for a 20 mile / 32 km drive on the Motorway before arriving at the testing station.

In sequence of common causes (and cost of fixing), high emissions are air leaks, HO2S sensors then cats. When troubleshooting, change ONE thing at a time then check for codes or you can never be sure what actually fixed it.

Graham

 

Dear Graham,

thank you very much. Yes, indeed thats what the mechanic said at our first emissions test. At that test the car failed the max. CO values for idle and 3000 rpm. The fuel was from March 2020 so I used up the old fuel (which wasn't that much), drove to the petrol station and filled up E10 for the first time. Also I added an fuel cleaner, which should help to pass the test. Then I drove the car for about 100 kilometres and went straight to testing. It was a rainy day and I had to wait, so the engine wasn't that hot anymore. This time he passed the 3000 rpm test, but failed the idle test.

I checked for air leaks with brake cleaner. Also checked the headers. Nothing. But I can hear a tiny whistle when the car is cold and accelerating. Maybe there is a small leak, but I am not sure if this leads to a 0,92 CO. The problem is that the best shop for me would be in "Essen", the Jaguar Land Rover Classic Centre Europe, which is about 500 kilometres away. :-/ Nobody is able to read the OBD here. Not Jaguar, not BOSCH, nobody. So I am on my own.

Alex

 

You don’t need to pay a shop to replace your oxygen sensors. There is enough access for you to do it yourself.

In the US, we have four sensors! You only have two. I would just purchase the sensors, put them on the car yourself.

 

£50 isnt much for an Autel scanner.....
In any event, your trim readings are not "pretty good" , but as Vee has suggested the short term trim readings look very odd. They should be moving around, and the flatline responses you have recorded suggest that your O2 sensors are dead, or your scanner isnt capable of reading them. The fact the scanner could read the long term trim would make me discount the latter possibility a little, which brings us back to replacing the O2 sensors.
You mention spraying brake cleaner to check for air leaks. That would work for vacuum leaks, but wouldnt work for exhaust air leaks

 

Hey,

thank you, yes you are right, 50 € wasn't much, thats why I said it. Well, I measured the trims in idle, not touching the accelerator. Maybe thats the problem with the weird straight line? As far as I understood the 0% and 4,7% readings seem okay for idling. I am new to this, sorry. Im willing to change those O2 sensors on my own, but I am also afraid that they won't come out, brake off or damage something. Also I have to do it without lifting the car. I would like to drive the car and measure the trims again. Not sure which app is best for this task though.

They added a so called mini-cat after the "perfect" emissions test 2019 (CO was zero at 700 and 3000 rpm) which is located after the factory cats. Maybe they swapped the O2-sensor connectors by accident. Does anybody know what to look at if the connectors are connected the wrong way? Lumpy idle, misfiring? How do the fuel trims react if they are wrong please?

Thanks again for all your help!! :-)

 

Switch the oxygen sensors and the car won’t idle well at all. You’ll know something is wrong without the need for the Autel.

I had a similar problem with another car and it ended up being the ECU. The oxygen sensors were just flat, all the time. Couldn’t get them to swing based on what the engine was doing.

Let us know what happens!

 

According to my OBD Scan the car is at OL Open Loop! Shouldn’t it be at Closed Loop with 72 degrees? At OL the O2 sensors don’t work or am I wrong?

Is the coolant sensor ok? It should be because I have no fault codes and it shows 72 degrees? Or should I order a new one anyway? Is a VEMO spare part okay? Before I got the Autel I scanned with the ELM327 on Septemper, 4 th. and the android app also showed the 72 degrees. Thats odd. Also the app stated open loop because of low engine temp. So its the sensor or the thermostat is stuck, right?

 

That is great news! The Coolant Temp Sensor can indeed prevent the car from going into closed loop!!!

That could also explain the flat oxygen sensor readings!

It is both easy to replace at home and inexpensive!!!

 

Yes, fingers crossed! I ordered the Vemo part today.

 

elm is not reliable

doubt this is your problem

 

does the sensor get hot when the car is in open loop? maybe its a stuck thermostat?

 

The coolant temperature sensor is important, and relatively inexpensive to fix. It could also be stopping you from entering closed loop. However, you should still be getting a reading from your O2 sensors, even in open loop.

 

Afaik the O2's are dead in OL mode, because they are not needed. The engine heats up quickly, the gauge stays in the middle (slightly left), cabin gets warm, AC works like new, never overheats or goes below middle ->> thermostat is ok.

BUT: can't check it right now: maybe the fluid level is too low. ->> sensor not deep enough in the coolant.