Help please. Had the dreaded EM light come on a few days ago and booked it in with the Indy that I have used and trusted for years. Codes showed that the O2 sensors needed replacing which he did. He also did a full scan and reset the adaptions.
The car is now running beautifully but the light is still on. He assures me that it will need a few drive cycles to re learn and that the light will go out . How long should that take ?
Cheers.

 

BLues, in my experience, the light went out and stayed out after replacing the sensors. So, I would be giving say 100 KM and then 5 starts after that. Of note, a "start" is starting the engine, getting 10,000 revolutions out of the engine (about 5 minutes of run time) and then turning the engine off. On the 6th "start", the light will go out if no error codes have been seen in the previous 5 "starts".

 

Cheers Thermo..Did your EM light go out immediately after replacing the sensors or did you need to go through the run cycles ? I was wondering if it was the extra scan and reset of adaptions that was causing it to need to relearn or if it is usual for it to need drive cycles to put out EM light after replacing both upstream 02 sensors.

 

I didn't reset mine after replacing a bad sensor and the EM light went out after a few daily commutes as Thermo advised.

 

Sounds like I need to be patient for a few days then.I asked my guy if he had reset it and he said he had but the light would still stay on for a few cycles anyway whilst the car went through various remote checks.
I think I got confused as I thought clearing the codes after fixing the sensors would put the light out straightaway .

 

Clearing the codes should put the MIL (aka EML aka CEL) off - but it also clears all OBD monitors (often used for such as smog tests).

If the codes really were cleared but the MIL is on then there's a fault.

Note that until OBD monitors set again (re-set, not reset) many codes cannot flag so you can be in Catch-22 wondering what is wrong...

 

Am even more confused now ,not sure if the light should have gone out straightaway or if it will re-set after a few drive cycles.
Spoke to my mechanic again and he said it was also showing code P1582 flight recorder data and it will need several drive cycles to re learn as he has re-set adaptions.
He reckons that some ,but not all faults will put the EML out immediately when they are rectified but others need to go through run cycles after rectification before the EML will go out.
TBF I have used this guy for more than 30 years and trust him completely and he has said that if the light doesn't go out in a few days to go back and he will put it back on diagnosis for free.

 

The light on my car went out immediately after starting the car first time after changing a sensor. I was so happy that I haven't even tried to check for any other recorded faults.

 

Well a quick update on this.My indie has now changed all four sensors but still the eml stays on with the code for faulty O2 sensor bank one.Have changed the 2 upstream sensors round to see if one of the new sensors was faulty but still the same fault keeps showing on bank one.Have checked both the fuses and they are both fine.The car is running beautifully.
Help!

 

See if the light extinguishes after you have done 5 short runs of about 5 minutes each minimum.
If it doesn't resolve then you might also need to check continuity from O2 sensors back to ECM to make sure you haven't got a fractured or corroded wire.

 

Cheers Mark will try those driving runs over the next few days.. If that don't clear it will have a look at the wiring.Also had a thought as to if the maf sensor may be causing a problem.
Failing that there is a decent car Sparky a few miles away so may drop it in there for him to have a look at.

 

BLues Boy, you may want to try 2 things. The easier one is to find a long up hill out in the middle of no where. Then what you want to do is to start out slowly at the bottom of the hill and then do a long, hard pull up the hill. What you are doing is getting the catalytic converter as hot as possible. This is going to help convert some of the solids in the cat to a gas, freeing up the cat. You may want to do this long pull say 5 times or so. Up to you. The only caution is if the check engine light starts flashing, IMMEDIATELY back of off of the gas to get it back to a solid light.

The second thing to try is getting a product called "Seafoam". It will come in a 1 pint container. What you are going to do is find a 6 foot/2 meter hose and tap it into a vacuum line and pinch off the other end and run it out of the engine bay. You are then going to start up the engine with it already pre-warmed up to normal temp and get it to an idle. Then raise the engine RPMs up some (2,000 RPMs or so) and then open up the hose and stick the end of the hose into an open can of Seafoam. You are going to have to step on the gas to keep the engine runnning, but you are going to want ot let the engine suck down about a 1/3 of the can and then let the engine die (sucking down more of the can - remove the hose if you hit a half can). You may notice that the car will start to smoke some. This is normal. Let the car sit for 5-10 minutes and pinch off the end of the hose again. Start the car (yes, it is going to be hard to start, but it will start). Get it to where it will idle. Raise the engine RPMs up to 2000 and suck down the rest of the bottle of Seafoam. At this point, you may see the car really starting to smoke. I am not sure why, but not all cars will smoke a lot, some just smoke a little bit. Whatever you have, get the car back to the point that it will idle with the hose pinched off and the can of Seafoam gone. Remove the extra hose and restore the engine bay back to normal and take the car out for a drive. You are going to want to put the J-Gate into say 3rd and get the engine RPMs, down to say 1,000 and then do a hard pull up to 4-5,000 RPM, slow down, then repeat, repeat, repeat. This will help clear the smoke. After about 10 minutes, the smoke should be gone. I would say then to clear the codes that your car has (this process may introduce a few new ones like a loss of vacuum code - P0171/P0174). This may clear the code.

 

Cheers Thermo. I will try the hill drive tests next week and then look at the Seafoam one if it doesn't work.
Have been looking at the Seafoam products and am not sure which one to get

 

Blues Boy, get the one that says "motor treatment". When I did this to my X-Type, I used the brake booster line that plugs in on the top of the intake. It was a nice easy place to attach to. Just have to find the right size hose that fits in that hole.

 

A quick update on this.I tried the hill starts and also a few long runs but still got the EM light on.Called back into my mechanics today and he did another scan for free. She's now showing two codes indicating that both upstream sensors (both new) are not functioning.To be fair to him he says that if I leave it with him he will change out the two new sensors for a pair of Denso original equipment with no labour charge and just a charge for the difference in price between the aftermarket pair and the Denso's. (About £60 the pair)
Here's hoping !

 

Just to confirm, you have checked the two 30A fuses in the front power distribution box F20 and F21?
They power the heaters within the four O2 sensors.
The two upstream sensors do not share the same fuse, so one upstream and one downstream sensor are on each fuse.
Just hate for you to go through sensor changes for what might be a couple of dickie fuses

 

Yea,have checked them, both fine

 

Let's hope that the genuine Denso O2 sensors get you sorted.

 

Cheers Mark,I really hope so .I have put a lot of time and money in getting her into top nick and this is so frustrating as she is running spot on.
Oh well ,the Denso's will be with the mechanic on Monday so hopefully will be sorted.

 

Wrong list, sorry