Disco 3 (LR3) 2008 XS - Limp Mode - P0403 Code--Help Please

Hi Folks. HELP PLEASE!

I Have owned my two owner 2008 Discovery 3 tdv6 xs manual Gearbox for 3 years and generally has been a good solid reliable runner, when it runs I love it--right now not in love!! - 128k on clock FSH new MOT, repairs of late (4 months) I have:
1. New Clutch - corrected slipped and EPB warning
2. 2 x New EGR (one stuck one sheared)
3. Replaced Wiring Harness
4. Service and new bushes

combination of lockdown and service reparis means I have seen little of this car

I recived it back a week ago and yesterday it dropped back into Limp Mode
Limp mode will not clear by restarting engine multiple times but only if I leave car overnight then it will clear for one short trip before returning.(perhaps after engine warms up?)
I got a `cheap and I know i shouldnt but was only one that would arrive next day' reader to reset code/EML after limp dropped, now it has come back and nothing will clear it--code clears--then comes back
reader states EGR Control Circuit P0403 error

I am not a great DIY mechanic and it is bank holiday so not much help out there if this is an easy fix?? I have read around but would be interested to get best guess here:
1. Battery? using the `secret menu' it shows 12.5v off and 13.5v driving
2. Turbo Actuator? ? engine runs and revs fine (obviosuly doesnt rev in limp mode), no issue with engine idle, no misfiring etc..
3. EGR solenoid? but thought this was sorted by garage when they did egr and had this fault before--but not sure if it was changed
4. I read on one link somewhere that i havent found since that having changed the EGR mabe ECU needs reprogramming at LR Dealer????
5. Anyone go better ideas? thoughts on what order I should perhaps look at these and advice on how to fix if possible DIY easy fix!
Big asks I know....

finding the right thing to fix and fixing it is not my forte but frankly prepared ot try anything right now--any help much appreciated thanks

Hi

can u remember the 2 x numbers after the P0403 plse

What code reader did u get please as indeed sometimes they can throw a false code, can u get live data as well or just read them

thks

gstuart said:

Hi

can u remember the 2 x numbers after the P0403 plse

What code reader did u get please as indeed sometimes they can throw a false code, can u get live data as well or just read them

thks

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thanks for replay--yeah i did see other comments about better readers giving further numbers (concede that on hindsight it was not a smart purchase)--my reader was cheap as chips--only purchased to clear engine warning light as limp had dropped--it only gives p0403--as generic code--sorry if thats not enough to go on

no live data nope

Cackhanded said:

thanks for replay--yeah i did see other comments about better readers giving further numbers (concede that on hindsight it was not a smart purchase)--my reader was cheap as chips--only purchased to clear engine warning light as limp had dropped--it only gives p0403--as generic code--sorry if thats not enough to go on

no live data nope

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no probs , know these can throw tantrums and can be hard trying to pin it down, alas that code can also cover

Good u tested ur battery as indeed a low one can cause a lot of issues

assume ur EGRs arnt blanked, u can blank them but alas needs a software update patch

u can get a reader for around £50.00 called an Autel AP200 or the one I have and many others here are a gap iid, but are around £440.00 , as that does suspension calibration and virtually everything that ur ever need

u could get someone to turn the key on and off for u and listen either side of the engine to see if u can hear the egrs moving , plus don’t get confused with the turbo actuator as that also cycles on/ off when the ign is turned on and off

also check the connection on the egrs , just in case

to be honest u really need a code reader that will at least do the live data , the Autel does that, think amazon sell them

know that doesn’t really help u now , along with it shouldn't be driven if the egrs are stuck

gstuart said:

no probs , know these can throw tantrums and can be hard trying to pin it down

Good u tested ur battery as indeed a low one can cause a lot of issues

assume ur EGRs arnt blanked

u can get a reader for around £50.00 called an Autel AP200 or the one I have and many others here are a gap iid, but are around £440.00 , as that does suspension calibration and virtually everything that ur ever need

u could get someone to turn the key on and off for u and listen either side of the engine to see if u can hear the egrs moving , plus don’t get confused with the turbo actuator as that also cycles on/ off when the ign is turned on and off

also check the connection on the egrs , just in case

to be honest u really need a code reader that will at least do the live data , the Autel does that, think amazon sell them

know that doesn’t really help u now along with it should be driven if the egrs are stuck

Click to expand...

Thanks again for quick reply.

I was starting to think i will have to fork out for a better diagnostic tool--got this one as I thought I might be just a tool to turn off eml...

on EGRs I am fairly comfortable that they are in themselves OK--wont be stuck as one fitted december and one fitted 2 weeks ago and both checked over

though are you saying the solenoid issue might control whether I hear them opening and closing? and hence point to that?? I understood they dont open until engine is running at temp anyway?

guessing I am off to Amazon--not rushing for the IID tool--partly because for the cost and the length of time i currently intend to keep the car (am not loving it this year!!) dont think it would pay back...

have seen a few around will look up your Autel which looks a good price--though had seen Icarsoft as a recommend also?

thanks for help

I have looked at the Autel AP200 onlien--looks well priced and can be delivered--if this is a recommend then I may well order?

Cackhanded said:

Thanks again for quick reply.

I was starting to think i will have to fork out for a better diagnostic tool--got this one as I thought I might be just a tool to turn off eml...

on EGRs I am fairly comfortable that they are in themselves OK--wont be stuck as one fitted december and one fitted 2 weeks ago and both checked over

though are you saying the solenoid issue might control whether I hear them opening and closing? and hence point to that?? I understood they dont open until engine is running at temp anyway?

guessing I am off to Amazon--not rushing for the IID tool--partly because for the cost and the length of time i currently intend to keep the car (am not loving it this year!!) dont think it would pay back...

have seen a few around will look up your Autel which looks a good price--though had seen Icarsoft as a recommend also?

thanks for help

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your so welcome and so nice thats it appreciated m reason I say that is sometimes we help someone and don’t even get a please or thank u back , very refreshing for a newbie to show appreciation

indeed u should be able to hear them move , it’s part on an anti seize software program as the ign is turned on and off

where abouts in the UK are u plse

U may have an issue with - fuel filter , low pressure fuel pump, Map/ Maf sensor so indeed with the other letters can help

Indeed that’s why I thought about the Autel depending on ur budget , particularly it having the capability of reading live data , u can then see what % the egrs are opening , etc

must admit the gap iid paid for itself very quickly seeing local dealer charges £180 per hour plus vat

plenty here to help so don’t ever think ur on ur own

hope that helps a little

gstuart said:

your so welcome and so nice thats it appreciated m reason I say that is sometimes we help someone and don’t even get a please or thank u back , very refreshing for a newbie to show appreciation

indeed u should be able to hear them move , it’s part on an anti seize software program as the ign is turned on and off

where abouts in the UK are u plse

U may have an issue with - fuel filter , low pressure fuel pump, Map/ Maf sensor so indeed with the other letters can help

Indeed that’s why I thought about the Autel depending on ur budget , particularly it having the capability of reading live data , u can then see what % the egrs are opening , etc

must admit the gap iid paid for itself very quickly seeing local dealer charges £180 per hour plus vat

plenty here to help so don’t ever think ur on ur own

hope that helps a little

Click to expand...

it does help and is appreciated. is there a specific Autel AP200 I shoudl go for? there seem to be a few

Cackhanded said:

it does help and is appreciated. is there a specific Autel AP200 I shoudl go for? there seem to be a few

Click to expand...

good to hear , apologises should have said, from what I’ve read theres 2 x of them

one white and the other red, the red one I’m lead to believe a subscription is required where the other one doesn’t

personally I just recently bought a white one as handy to keep it in my glove box

here’s the link of where I bought mine

https://www.autelstore.co.uk/wholesale/autel-maxiap-ap200-bluetooth-scanner.html

also where abouts are u in the uk plse as wondering if someone may be near u

hope that helps

The icarsoft i930 is about 100 quid, and if you sell it 2nd hand you will get 1/2 to 2/3rds of your money back easily.

gstuart said:

good to hear , apologises should have said, from what I’ve read theres 2 x of them

one white and the other red, the red one I’m lead to believe a subscription is required where the other one doesn’t

personally I just recently bought a white one as handy to keep it in my glove box

here’s the link of where I bought mine

https://www.autelstore.co.uk/wholesale/autel-maxiap-ap200-bluetooth-scanner.html

also where abouts are u in the uk plse as wondering if someone may be near u

hope that helps

Click to expand...

Hi Many thanks for your help so far.

so Autel Ap200 arrived this pm. Set it up and went for a look see.

just to remind all I am thicker than a whale omlette, so be gentle

so on start diagnositc it found shed loads of hisotirc and intermittant faults which i cleared, then i ran the engine in idle with faults clear.

the code for EGR fault was P0403-00

with fault clear i ran for about 10 mins looking at love data ( playing with buttons rathern than having clear understanding of what i was about)

initially the egr control sat at 5%
The egr units 0/1 bith ran around 25% hiking to 37-40% when i revved

after a bit of looking at batteries and height control i found myself back at egr live data
and suddenly noticed that with engine temp now close to nirmal run the egr control said 5%

however the two egr units showed 0%

strange thought I, i revved to see if anything happened and engine fault message came up

P0403-00

so seems initially egrs were working the. As engine got warm they stopped??
Any thoughts? Anyone?

noting both egrs have been replaced , 1 december and other 3 weeks ago
And in answer to final question
Colwyn Bay in North Wales.

thanks

Quick add on ran diagnostics again got
P0403-00
UO401-94 Atcm invalid data received from ecm/powertrain, which i assume is special functions being off for fault.

EGRs 0/1 both showed 0% and fault would not erase and reset.

thanks

Hi

thanks for the update , plse don’t sell yourself short

just going to add some notes and an explanation at the end , will be over several posts as just finding some of my notes and a plan for u


The combined EGR modulator and cooler is located under each cylinder bank, between the exhaust manifold and the cylinder head.
The cooler side of the EGR is connected to the vehicle cooling system, via hoses. The inlet exhaust side is connected directly into the exhaust manifolds on each side.
The exhaust gas passes through the cooler and is expelled via the actuator and a metal pipe into the throttle housing.
The EGR modulator is a solenoid operated valve which is controlled by the ECM. The ECM uses the EGR modulator to control the amount of exhaust gas being recirculated in order to reduce exhaust emissions and combustion noise.

**** The EGR is enabled when the engine is at normal operatingtemperature and under cruising conditions.******

The EGR modulator receives a 12V supply from the main relay. The ground for the solenoid is via the ECM and is controlled using a PWM signal.
The PWM duty signal of the solenoid ground is varied to determine the precise amount of exhaust gas delivered to the cylinders.

The modulators are operated through their full range at each engine start-up, to clear any carbon deposits that may have built up whilst the engine was running

In the event of a failure of the EGR modulator, the EGR function will become inoperative. The ECM can monitor the EGR modulator solenoid for short circuits and store fault codes in the event of failure. The modulator can also be activated for

As I’m finding the notes , do u have a multimeter and what wiring harness did u replace plse thks

gstuart said:

As I’m finding the notes , do u have a multimeter and what wiring harness did u replace plse thks

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thanks again and appreciate oyu pitching this at the level of my knowledge--which is pretty much non existant--since i let my MGB go 30 years or so ago my ability to self mechanic has been limited
multimeter is a stretch--bur may have one somewhere that I have never used can go searching

wiring was this part:

Discovery 3 TDV6 Engine Wiring Loom Land Rover 7H2Q 9H589 AG Euro 4

( I didnt buy this new from LR as it was quoted at 2.4k--ebay salvage part....)


(though am beginning to wonder whether that wasnt the issue in the first place!)

Cackhanded said:

thanks again and appreciate oyu pitching this at the level of my knowledge--which is pretty much non existant--since i let my MGB go 30 years or so ago my ability to self mechanic has been limited
multimeter is a stretch--bur may have one somewhere that I have never used can go searching

wiring was this part:

Discovery 3 TDV6 Engine Wiring Loom Land Rover 7H2Q 9H589 AG Euro 4

( I didnt buy this new from LR as it was quoted at 2.4k--ebay salvage part....)


(though am beginning to wonder whether that wasnt the issue in the first place!)

Click to expand...

@Cackhanded

many thks , right so I think that puts abit of a spanner in the works , tell u for why , as that’s such a big loom is as u can imagine go to a lot of sensors, ecu’s etc

so if you can get hold of a multimeter think we can do some other tests

1) wish to rule this out first , remove ur battery , ur then see 2 x modules hidden behind a plastic cover , first one will be ur TCM module , that is for ur transfer box, next one is the ECM, engine control module , that sends power and controls ur egrs , there’s known reports of the pins getting dirty/ green or broken which can cause all sort of issues, intermittently throwing codes etc , so plse check that so we then know if it’s ok or not

2) I’m not 100% if that looms includes the egr connectors

3) have u cleaned ur MAP sensor , which sits in top of ur throttle body

so if u wouldn’t mind checking those above please we can go through it step by step , at the end of the day IF the egrs are found to be faulty there’s some options, 1) replace them , 2) blank the egrs and get a software patch done

but won’t cross that bridge before we know 100% if there at fault again but feel there’s something else going on, alas will be back and forth but more than happy to help all I can, plus others here who are also very knowledgeable

hope that helps give u a direction of where to go by starting at the ECM , cleaning MAP sensor , ( please ensure u don’t poke anything down the sensors hole, use some MAP sensor cleaner

hope that helps

Also we’re the EGRS replaced as a whole unit and we’re they genuine plse,thks

plus where abouts in the uk are u plse

gstuart said:

@Cackhanded

many thks , right so I think that puts abit of a spanner in the works , tell u for why , as that’s such a big loom is as u can imagine go to a lot of sensors, ecu’s etc

so if you can get hold of a multimeter think we can do some other tests

1) wish to rule this out first , remove ur battery , ur then see 2 x modules hidden behind a plastic cover , first one will be ur TCM module , that is for ur transfer box, next one is the ECM, engine control module , that sends power and controls ur egrs , there’s known reports of the pins getting dirty/ green or broken which can cause all sort of issues, intermittently throwing codes etc , so plse check that so we then know if it’s ok or not

2) I’m not 100% if that looms includes the egr connectors

3) have u cleaned ur MAP sensor , which sits in top of ur throttle body

so if u wouldn’t mind checking those above please we can go through it step by step , at the end of the day IF the egrs are found to be faulty there’s some options, 1) replace them , 2) blank the egrs and get a software patch done

but won’t cross that bridge before we know 100% if there at fault again but feel there’s something else going on, alas will be back and forth but more than happy to help all I can, plus others here who are also very knowledgeable

hope that helps give u a direction of where to go by starting at the ECM , cleaning MAP sensor , ( please ensure u don’t poke anything down the sensors hole, use some MAP sensor cleaner

hope that helps

Click to expand...

thanks--Map Sensor I can certainly manage--that sits within capabilities - though it may be tomorrow when i do it--as the rain is coming odwn and it is in the open

with regards the EGRs--they were new and whole unit but not wholly sure if they were aftermarket or oem tbh...was done by indy garage who, to be fair and sure he would agree, is better on Defenders than discos we have established

I have been pointed at another specialist indy in the area so may end up going there--but MAP--that I can do so will try that first and if the weather holds tomorrow have a punt at the pins behind the battery

thanks

gstuart said:

Also we’re the EGRS replaced as a whole unit and we’re they genuine plse,thks

plus where abouts in the uk are u plse

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Oh Sorry--did reply early but probably got hidden int he noise of my bleating

I live in Colwyn Bay which is in North Wales.

Cackhanded said:

thanks--Map Sensor I can certainly manage--that sits within capabilities - though it may be tomorrow when i do it--as the rain is coming odwn and it is in the open

with regards the EGRs--they were new and whole unit but not wholly sure if they were aftermarket or oem tbh...was done by indy garage who, to be fair and sure he would agree, is better on Defenders than discos we have established

I have been pointed at another specialist indy in the area so may end up going there--but MAP--that I can do so will try that first and if the weather holds tomorrow have a punt at the pins behind the battery

thanks

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no probs

so indeed please let us know how u get on with the Map sensor and seeing if the ECM module is all ok

no probs with regards to the weather as also very windy/ rain here

Cackhanded said:

Oh Sorry--did reply early but probably got hidden int he noise of my bleating

I live in Colwyn Bay which is in North Wales.

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that’s ok , more than likely I missed it, lol, i just thought in case u was in the kent area could have helped u, 2 x heads better than 1 and all that