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

Hey guys,

So I have finally hit an issue with my Grand Cherokee. I am quite scared at the moment because I don’t know how severe it is.

So this afternoon just leaving work when I started her up the engine slightly shuddered and started which gave me a bit is a scare as that’s not usual and then next second the check engine light came on. But the car was running so smooth and idled nicely. Checked in the engine bay quickly and nothing obvious was there so I carefully drove home because I didn’t that’s my tablet to check the code.

Upon coming home I checked the code and this came up. I tried to clear it but once cleared it comes back again in a few seconds. Haven’t started the car since clearing though. But the car runs so smoothly and fine. All temps normal and also no problems accelerating or idling at the moment. Subsequent starting of the engine seems to be fine too. Before clearing the codes I stopped the started the engine a few times and it felt okay. Might have to drive for a bit and see if the check engine light goes away but I doubt it. Under the code it says ‘permanent’ too. Couldn’t upload the screenshot here wouldn’t let me.

I am no mechanic so what do you think is my issue at the moment and am I in big trouble here? ��

Any advise would be great. Thanks guys.

Check list shows this for that code:

"" Description:
The Throttle Valve (TV) Actuator is an electrically operated throttle valve motor that controls the amount of fresh intake airflow to the Intake Manifold. The TV Actuator is sometimes referred to as the ‘EGR Airflow Control Valve’. This does not refer to the ‘EGR Valve’ (which is a separate device). One function of the TV Actuator is to modulate the quantity of airflow during DPF regeneration for optimal exhaust heat. The Powertrain Control Module (PCM) controls the TV Actuator using DC voltage across 2 H-bridge circuits (+ and —). When the PCM closes the throttle valve (creating a low pressure vacuum in the intake system), this low pressure effect helps draw exhaust gases from the EGR Valve into the intake system. The TV Actuator has an internal position sensor. The PCM receives feedback from the sensor to indicate the position of the throttle blade. The position sensor operates as a typical three wire sensor. During Diesel Particulate Filter (DPF) Regeneration, the EGR Valve is closed and only the Throttle Valve allows (fresh) intake airflow to enter the Intake Manifold. ""

Its confusing but I believe it refers to the valve which is located where the hose connects to the intake manifold ............ possibly some crud or the valve gearing is failing, I would pull the hose off and have a looky to see if the flap is jammed or gunged, if the pplastic gears are starting to fail replacements are available here; https://www.ebay.com.au/itm/12473009...SABEgLj4PD_BwE


The code may reset after 6 or so starts.............you don't want to look at a genuine Mopar badged part.....

Thanks for getting back to me mate yes it’s really confusing but I’ve read so much about this and also read the bit you sent last night that I fairly understand what’s going on. It’s very electrical this sensor and a sensitive threshold set.

It’s not to bad if the part required is what you have sent. I just don’t want to take it and some mechanic goes to replacing the PCM or something like that which I have heard is rare to break. I know you guys are good at visually inspecting things like this before hand.

When you say pull the hose off are you able to tell me exactly which one or a picture of this place and hose I need to be looking for? Sorry I am not that great with these and this engine feels so complex plus don’t want to pull apart something I can’t put back.

Is it attached to throttle body and MAF? Again I need to check how I get to these.

This has to be rare for the Jeep because all I found online was this particular error
Code appearing on RAM ecodiesel owners and not found it on one Jeep owner. So really hoping this is a one off thing. But could be the start of it failing and early warning. Hoping it’s some dirt/debris thing.

I am going to start her up this morning and if starts okay, keep
Driving and like you said they do say that if the electrical
Voltages sent back to PCM goes normal in the next few starts it would
Clear the CEL. The severity is low most of the time apparently too so hoping for the best here.

Thank you ����

The MAF is the bit on the back of the air filter, so not that, the "what is sometimes called the throttle body" is where the big fat intercooler hose plugs onto the engine is what you want, prick of a fitting.......... If it runs nice and the code goes then all is good, it is happy but if your not confident in pulling bits off then best to find a spanner man who knows what he is doing but they can be poking around in the dark as well... check the connection on the valve body as I doubt its the ECU, when it goes the dash usually turn into a xmas tree.

yes its definitely not the ECU having issues.

I have a development this morning. Started the car up and it started smoothly and the check engine light went away. So let the car warm up a bit and then before I started off thought let me turn it off and crank again to see if it's okay. The second crank wasn't smooth in fact the car cranked for about 2-3 seconds before it fired up almost like it was choking with no fuel. The CEL wasn't there. Did another one (third one at this stage) and it started okay but the CEL came back up.

So the PCM is definitely sensing the issue and it is also able to clear the CEL when it is okay. Looks like the issue is intermittent too. This valve isnt closing at the correct place when the car shuts down sometimes. Does the CEL go away after a few ignition cycles by itself or do I need to clear the code and then a few ignition cycles for it to disappear?

Also looks like I will have to get this looked at for sure because something isn't right. Only during the starting this happens though and when the car is running, it runs smoothly with no difference at all. No loss of power and fuel consumption all good.

From what I have read it does look like the gears that move the butterfly valve maybe be failing, it has a temp sensor on the side of it, if you pull off the intercooler hose you should be able to see it as well as the butterfly valve, which when shut down should be fully open or maybe thats fully closed ???? Anyway if it just swings in the breeze its stuffed and the gearing has probably stripped., if on start up it gets stuck other than wide open then that will give you your rough idle etc, just like a hand over the air filter intake ........ while just guessing from what you have described it does seem the most plausable but I could be miles away from it.

I would give the temp sensor a good squirt of sensor cleaner just to be sure its clean ............. then go for a good burn....

https://www.ausjeepoffroad.com/forum...00b0a597d0.jpg


PS: Start the engine put seat belt on and drive away, a sits ready to go, any sort of idling just lets more soot into the engine.....

Thank you so much for sending through this information and markup. This will help me to have an initial look when I get a chance. Confident that I can pull that temp sensor out and reseat it. Been so busy and I am still using the car like nothing happened.

Been driving it around today and I had to start it a couple of times and she started fine plus drove fine. Also the CEL has cleared at the moment too. So it has to be some gear not opening/closing like it should during the shutdown. Surely they use strong metal gears for these things - nope.

I will keep you updated thanks so much for the advise. It's a huge relief knowing I got you guys around here for advise instead of running around like a headless chook lol