P02E8 Diesel intake air flow “a” position sensor circuit low

[vijith555]

Also need to add whether it helps or not is that fact that the last two attempts by garages to read the error code plugging into tot he OBD port under driver side did not work for them on their machines. We had to use the bypass secure cable side on passenger side. I thought this was odd because you only need to connect to passenger side to write anything or clear anything. Readings should still work on driver's side. I have not tried mine on that side recently but remember it being able to ready all before.

But I just removed the OBD BT adapter I had connected always now. Going to run without it for a bit. Anything can be suspected at this stage.

[FARWEST]

Check the GDL Auto utube clip re factory security on '18's onwards...thereis a cable that is required to bypass tge factory security settings.....available scanners cannot enter selected modules without the use of this fitting

[drover]

Originally Posted by FARWEST

Check the GDL Auto utube clip re factory security on '18's onwards...thereis a cable that is required to bypass tge factory security settings.....available scanners cannot enter selected modules without the use of this fitting

I mentioned that before with a link to the Alfa OBD site which gives a good explanation of the problem, just a sneaky way for Stellantis to try to get people to use dealers and not DiY there own diagnostics.

[vijith555]

Sorry guys didn’t mean to mislead you but what I was saying is the scanners at shops were not able to ‘read’ anything from the standard port on drivers side which is odd. Because you can always read from that side but not make changes.

I already have the security bypass cable attached and ready for adapters on the passenger side. That’s where I connect my BT OBD device too which lets me read and make changes on the fly. Haven’t had problems with it.

Small update - I’ve started to start the car without doing the two step delay I.e just get in and press button with foot on brake and after a couple of starts the CEL is up again. But what I have noticed now is the engine cranks and starts with absolutely no hesitation or choking. So I am going to start like this and let the ECU clear itself again. I am happy to find the starts are strong now. Probably the MAF clean helped too.

I am beginning to suspect this is a battery issue now. Could be wrong but when I had a weak battery before I got it replaced whenever I started the car I’ve seen the volts drop close to 9v. When the. When the new battery was installed this number went up to like 10.5-11V during crank. I keep the battery gauge on EVIC up when starting to see this. It’s not accurate as a multimeter on the battery itself but a good indicator. Definitely getting the battery tested next week.

Who knows a slightly weak battery during the start could be under powering the throttle body and that is going into a fit or sending a CEL..possibility maybe. Keeping the OBD device unplugged for the next few days so there shouldn’t be any drain whatsoever. And till the battery test I cannot say it is at fault..usually this car shows other errors when the battery is low and I have not seen any of that this time around..

[vijith555]

Hi everyone its been a while since the last update on this thread so I thought of coming here and giving everyone an update.

First of all I am happy to report the issue has been resolved! It has been over 6 months of driving daily with a CEL that came on and off. Plus the difficulty of starting the car in certain situations but kept on going somehow. So towards the last few weeks I went to auto electrical places in hopes of getting my wiring tested according to documentation and standard troubleshooting for this code from Jeep - specifically the wires going in and out of the throttle body. But only had some of them say sorry they cannot diagnose this car at all and had another guy keep the car for the day and say their scanner tool cannot connect to my car with full functionality (secure cable issue 2018 onwards). He kept saying it is illegal by Jeep to do this as apparently only a few scanners or the Jeep official one can scan/make changes on these 2018+ models. I told him I could do more with my BT adapter and JScan and just left. This workshop also told me I should just get the throttle body swapped instead of spending time looking at wiring because they said it would be super rare for the wiring on a 2018 to be deteriorated anywhere as it is young and they would expect this to happen in much older vehicles. And yes the connectors whenever I have inspected looked new.

Then finally I said f$#@ it I am going to take the risk - i.e. not testing cables and going for throttle body swap straight away because I had enough and the clock was ticking to the day this car would go into limp mode should the throttle body fail completely. By this time I had enough data and experience to say it has to be the throttle body (the longest testing and observations anyone could do). Went to the first Jeep garage mechanic I spoke to 6 months ago who had said without any hesitation this code is talking about the throttle body position sensor just a swap fixes it.

Got the throttle body swapped for a good condition used one he had available (I know the recommendation was to go for brand new but I had no guarantee this was going to fix it and was a gamble) and guess what - it was the throttle body all this time! The CEL went away and car started smoothly. Been running for almost two weeks now and touchwood it has been good. Also I can confirm now there is no requirement for a driver to wait for 1 and half minutes after shutting down the engine before they could start it up again as that was my case for the last 6 months. Now I can turn off the engine after a drive and almost instantly start it up (in case I really need to) again with no issues because the throttle body is not hunting for position as the sensor had gone bad previously. Also many Jeep guys said the car should be able to crank up there is no waiting required. So yeah I have been CEL free and no choking while starting anymore. I am so thankful my original throttle body gave me so much time without failing completely on me.

As a safety measure I asked the workshop to give me my original throttle body so I can keep it as a spare in case something happens - as I know this throttle body would still work if swapped back with just the electrical sensor gremlin. Remember how you guys wanted me to check the inside plastic gears of the original throttle body? I finally got the chance to look inside and it looks brand new! Not even dust or any cogs damaged. Pictures attached. So even if I was successful taking out the throttle body to inspect, that would have left us with nothing. This was purely the position sensor circuit fried issue. It somehow managed to work all these months with limited functionality which was remarkable.

I would like to thank everyone here again for their time and efforts in trying to solve this mystery. I learnt a lot of valuable information about these engines during these last few months and this was a tricky one - no doubt! Hopefully the information on this thread could help anyone who may experience a situation like this or similar

Interior of the original throttle body with the P02E8 issue without any cleaning:

[drover]

Well thats good news especially since you now are more familiar with the engine, once I had checked connections and pulled apart the throttle body, saw the cogs good,the circuit board would have been my prime suspect for sure, I wasn't aware there was one inside, the workshop manuals are pretty vague. Finding it and all other checks ticked off I would have replaced the whole assembly...........

....... My knowledge of these things has improved as well............. a long saga but I think many have learnt a lot from it, always better to learn from others than go thru it yourself.

[vijith555]

Originally Posted by drover

Well thats good news especially since you now are more familiar with the engine, once I had checked connections and pulled apart the throttle body, saw the cogs good,the circuit board would have been my prime suspect for sure, I wasn't aware there was one inside, the workshop manuals are pretty vague. Finding it and all other checks ticked off I would have replaced the whole assembly...........

....... My knowledge of these things has improved as well............. a long saga but I think many have learnt a lot from it, always better to learn from others than go thru it yourself.

Thank you Drover and yes I agree I learnt a hell lot more about this section of the engine which is good. Yes you are correct when you say upon inspection of the cogs being good, the circuit board would have been the culprit for sure but I was unsuccessful at physically taking out the bugger. Also in my case the main problem was I was getting no help from any of these local workshops to get this inspected. Also not one auto electrician was able to spend an hour to test the wires running from the PCM to throttle body which is step 1 for P02E8 issues. Just had to bite the bullet and go for it with so much uncertainty as it could have been anything at that point because it was not like the throttle body was dead with a service throttle body code which would have been easier to decide. And also the possibility of another sensor causing this issue was also on the table. Thankfully in the end, it was the throttle body. Some workshops even wanted to get my manifold changed to fix this and imagine if I had gone through all that!

Definitely a good end to this saga