Code reader, am I right in thinking...

Hi All.
here are the codes I read today
Foxwell Scantool NT520 Pro

Codes read on 2/3/2020

Air Flow Circuit logged low

Manifold Pressure Circuit logged low

Inlet Air Temp Circuit Fault logged high

Air Flow circuit logged currently active

Manifold Pressure Circuit Logged Currently Active

Inlet Air Temp Circuit Fault logged Currently Active

Inlet Air Temp Sensor in Backup

Air Flow meter in Backup

Man Press Sensor in Backup

Now I am rubbish at all the modern electronics, as a few of you know (!). I have been having what I think/thought were gearbox woes. However, as the gearbox seems to now be running a bit better, having ensured the ATF is up to the right amount and having run the vehicle around a bit, I am wondering if my problems might be more due to what these codes represent.
So. Am I right in thinking that these mean that the IAT sensor, the MAF sensor and the MAP sensor all need replacing, or at least cleaning?

If so, fair enough, but I am furious at the MAF sensor cos it cost about £127 plus VAT only November 2018.
Anyway I await the thoughts of those more up in all this than me. And tomoz I'll be out with the sensor cleaner before ordering them all if you think I should. Reasonably priced vendors of all stuff, all names welcome!

Stan

Hi,
1. first of all what year is your D2?
2. erase the codes then read again after a ride
3. the MAP and IAT readings are both delivered by the generically named MAP sensor.

whe'll speak again after you cleaned the sensors, cleared the codes and read codes again

Hi Sierra!
1/ My D2 is W reg, first reg April 2000, put it this way it must be a 10p engine I think.
Oh and EGR is deleted.
2/ These codes were present after erasing the codes and going for a drive, but obviously I hadn't cleaned them yet.
3/ from what you have said on other threads I gathered this is probably the case and the recommendation you gave was for either proper LR or Bosch number 0 281 002 205 if I need a new one.

SO! I'll clean the sensors, then clear the codes, then go for a drive, then read the codes again, then speak to you about them.
Here's hoping the cleaner works a miracle.
Thanks for your prompt reply.
Stan.

Right, since I lasted posted here is what I have found and done.
I removed all sensors, cleaned them and put them back. I also cleaned the plug to the MAP sensor and the red plug to the ECU which was still showing oil despite my having changed the injection loom a long time ago now and keeping on cleaning it. (what a pain).
Importantly I discovered that, DUH bigtime, after I had replaced the starter motor, I had left the MAP sensor unplugged! I had disconnected it to keep it safe while going through the usual performance to get the top nut off and back on.

So Codes cleared and the Disco taken for a spin.
It went like a scalded cat, comparatively. So I am hugely relieved.
However the code reader is not telling me all my problems have gone away, it now states:
Air Flow Circuit Logged Low
Inlet Air Temp Circuit Fault Logged High

Not being up in all this my assumptions as to the meanings of these may well be wrong.
The first one seems to say there is not a fault, and is perhaps just telling me i need to change my air filter. I am assuming that this is coming from the MAF sensor. But I really am not at all sure about this. But at least there is no fault so maybe the MAF is now working.

The second one seems to be telling me there is a fault, where, I don't know, but I am thinking this may be in the sensor itself. It is a Bosch one but I have never changed it. And again, it was logged after I simply started the car, let it tick over for a little while then took for it for a mile or two spin. So the engine never got warm. So how the inlet air temp can be high I have no idea. Maybe if I had driven the car far enough to get it warmed up then the scan would have diagnosed differently and I am quite prepared to have been told that this is what I should have done. but I was so pleased at how it was driving that I just wanted to get back home and put the scanner on it.

Strangely neither of the times recently that I have done this has there been any indication that the EGR has been deleted on the scanner. Although it is deleted.

Put it this way, cleaning and reconnecting the MAP sensor has definitely made a difference to how it drives.
So I look forward to any advice you can offer me.

Stanleysteamer said:

The first one seems to say there is not a fault, and is perhaps just telling me i need to change my air filter. I am assuming that this is coming from the MAF sensor. But I really am not at all sure about this. But at least there is no fault so maybe the MAF is now working.

Click to expand...

yes, the MAF is working but there's not enough sucction for some reason

Stanleysteamer said:

So how the inlet air temp can be high I have no idea

Click to expand...

next time watch the live data for it... IIRC Foxwell can even record live data on memory card so if i'm not wrong better record a log from a longer drive and post it here then we'll see.... of if you never replaced the MAP/IAT sensor better bite the bullet and put a new one cos they used to get ''tired" as any other part then the readings are not 100% accurate anymore

sierrafery said:

yes, the MAF is working but there's not enough sucction for some reason
next time watch the live data for it... IIRC Foxwell can even record live data on memory card so if i'm not wrong better record a log from a longer drive and post it here then we'll see.... of if you never replaced the MAP/IAT sensor better bite the bullet and put a new one cos they used to get ''tired" as any other part then the readings are not 100% accurate anymore

Click to expand...

Sierraferry you are a gem.
I expect the suction is, as I thought, a new filter is needed. No problem there and pleased to see the MAF is still working.

Now comes the fun. I do see the microchip in the side of the Foxwell and I do have a MicroSD adapter, quite by chance. I have never used them but there is a slot that will take the adapter on my laptop.
I can also plug the Foxwell into the laptop via a USB cable.
I will read the instructions that came with it to see what I can do about recording the live data. As you already know, I ain't that good with modern computer stuff and I even find reading the handbook confusing but I will try hard to get something. But one thing I'd like to know. Will it download all live data from the ECU or can I get it to just download the data from the MAP/IAT? Or do you not know without looking at the handbook etc?
I'll get back to you and yes, I am quite prepared to have to buy a new MAP sensor, it is old enough to deserve one and a Bosch one isn't that expensive.

Thanks as always for your advice, sorry I am so thick on the electronics/computers side of things.
Cheers

I dont have Foxwell myself i've just played with one some time ago but i remember it's quite human friendly with everything so it should not be a torment to record some data with it

Just remembered, i've seen cases when the low air flow code was caused by the depression control valve cos it should close under load to not let too much crankcase pressure out, if the valve doesnt close well there can be excessive crankcase gasses in the intake then the sucction through the MAF is reduced. There is no way to check how that valve works so better replace it cos it's a plastic bit exposed to hot gasses. I consider it as a medium term service item and change it after every 20K miles or so... p/n LLN100140L , dont buy cheap sh*t

sierrafery said:

I consider it as a medium term service item and change it after every 20K miles or so... p/n LLN100140L , dont buy cheap sh*t

Click to expand...

Interesting. Thanks for that tip fery.

sierrafery said:

Just remembered, i've seen cases when the low air flow code was caused by the depression control valve cos it should close under load to not let too much crankcase pressure out, if the valve doesnt close well there can be excessive crankcase gasses in the intake then the sucction through the MAF is reduced. There is no way to check how that valve works so better replace it cos it's a plastic bit exposed to hot gasses. I consider it as a medium term service item and change it after every 20K miles or so... p/n LLN100140L , dont buy cheap sh*t

Click to expand...

Hi,
I'll change the air filter as part of the servicing I will do before we leave for France at the end of the month. I'll get it done quickly to allow myself enough time to get this part if I need it. I bet it has never been changed since the car was built. I am the first owner/maintenance person and I bet no garage would ever do it!

I've had a read through the manual to the Foxwell, it is reasonably clear but I am not sure how I could download tha live data to the laptop to enable anyone else to read it! Anyway, if there is a fault it looks like a new MAP is in order. Which isn't the end of the world!

Thanks again

MOT tomorrow, so cross fingers!