TD5 no start and C0573 fusebox connector ?!

Hi, sorry my english.

All step during September/October 2023.
I have a nanocom and AEG battery booster (+15A or boost +100A)

First :

this discovery have a bad IDM (water ingress on connector, turn signal problem and "B" blink on odometer)
bad BCU : after a battery teardown, locked (hazard light) and no EKA
bad RF on the roof : no fob
no ECU error logged

i have see and test the disco 2 times before the deal, no engine problem : no smoke, power and normal sound (and no rust)
finally, last owner make a engine flush + oil and fuel filter before my return travel
i have drove the on highway at 90KM/H (no risk) during 450km without problem
after this travel : on the next morning, great cold start without problem = i'm happy
after 3 day, i move the car to a parking without engine problem
after 3 another day, i recover the car and : it only started on the third attempt + very noisy pump ...

Since this failure (in my garden, thank you god ), i have work on the body (rust check, painting and cleaning) and electronic to save times + check all standard problem with fuel

- new fuel pump, 2 x fuel valve on filter housing, fuel filter and gauge on the fuel regulator : 4 bar, no leak and no more noise or cavitation from the pump => but still no start and just crank, no fuel = only starter
ECU = error crank high speed only, all injector "clic" during injector test
CKP = 190rpm, with another brand new CKP : same situation (and wire look ok)

- i have change the BCU (with EKA, basic 1/2/1/2), adding 2 fob and recover turn signal
- i have change the RF receiver on the roof : good detection, including from outside
- i have change my IDM with a good spare : turn signal ok
(i have clean my original IDM PCB with contact cleaner and a small brush : turn signal run again, it's now a spare part for me)
- ECU learn security code, lo red light on dashboard, no B or odometer blink = only the CKP high speed crank logged

Actually :

Last light i have clean the engine fusebox aera.
I have check all cable and connector : no rust, melted plastic or water ingress. Only dust/dry mud including ECU, contact cleaner on all electric connector.

I have found 2 surprise :

1 small white wire ?! not connected
1 red wire between C0573 and ground with the WAGO

After replace all part in good shape and removed the red wire mire = i have lost my starter.
I can see the clock dim + a clic from the IDM, i need to try with with a friend to list relay on engine side
no more ecu error, no red light blink on dashboard or immo on ecu with nanocom, bcu and fob = ok

Now, i need to learn how to check all basic element of a starter (wire, relay ...).

I can do the pressure regulator and its seals alone but I'm afraid to touch the injectors myself for the seals.
I am convinced that the problem is electrical and not fuel

Thank you for having the patience to read me and share information.

I can't wait to show you the result but this engine problem paralyzes the entire project and is becoming stressful because my departure is scheduled for January and I have to do all the front suspension as well as various preventive maintenance work to avoid a stupid breakdown in the sand of the desert...

transpalette84 said:

Hi !

I'm new here and i fall here from google with my key word "c0573".
I have a TD5 engine with no start (starter run but engine dont start = zero fuel, no smoke = nothing !).
I have check all classic stuff and i start to suffer some without solution for the moment (i have 4 bar pressure, new pump, new filter, new valve bleed and anti no return, new RF for 2 new fob coding with success, no ecu error including test injector with nanocom except crank high speed, new CKP sensor, no fuel leak ... dead engine : no fuel inside).
I rebuild the car, interior/exterior and all electric problem.
I have drive the car on 500km before the failure without engine problem.
Suddenly, hard to start 2 times and since : nothing.

But last night i have found this cable in my engine fusebox, i'm not the first owner and i know this car already have problem to start last 7 years.
I have found a super clean wago in the middle of dust and mud ... i have change BCU, IDM and RF receiver to clean all electrical problem but since it's start to never run again = its my solution ?
I test tomorrow without this modification.

A ground wire (red, to body) with the pin 2 of C0537 fusebox connector.

Some mud buth clean connector, i have the same fusebox in spare just in case.

Someone know this modification ?

I clean all the area before a new test after work.

Click to expand...

Welcome!

Did you mean C0573? C0537 is in the headlamp. But, C0573-2 is only used in North American specification vehicles and does not appear on the European wiring diagrams. Edit - just noticed the thread heading is C0573...

Have the injector seals, particularly the copper ones, been changed recently? Hard to start and then no start is often a symptom of seal failure, but yours seem to have happened more suddenly than is normal.

Good luck!

Hi

PopPos, yes C573 ou C0573.
I think C0573-2 but i'm not sure.
Any idea for a UE TD5 ?

No information for injector seal but, and yes it have happened very fast (on 4 days, after 10 or more start witouth problem, 500KM and the next day : 2 x failure to start at the first time, only the 3 launch correctly but for the time : noisy pump !

So i have check standard stuff for fuel.
During this time, i have change BCU (locked after battery removed and no EKA on original) & IDM + RF receiver to recover a odometer without "B" blinking, good turn signal and central door lock from the 2 fob (1 original et 1 one new)

So i hope this wire represent a old solution from old owner with other problem and now with my new BCU/IDM i need to remove this... to start.

Answer tonight for the wire.

I need to prepare the good extractor tool for injector this week.

transpalette84 said:

Hi

PopPos, yes C573 ou C0573.
I think C0573-2 but i'm not sure.
Any idea for a UE TD5 ?

No information for injector seal but, and yes it have happened very fast (on 4 days, after 10 or more start witouth problem, 500KM and the next day : 2 x failure to start at the first time, only the 3 launch correctly but for the time : noisy pump !

So i have check standard stuff for fuel.
During this time, i have change BCU (locked after battery removed and no EKA on original) & IDM + RF receiver to recover a odometer without "B" blinking, good turn signal and central door lock from the 2 fob (1 original et 1 one new)

So i hope this wire represent a old solution from old owner with other problem and now with my new BCU/IDM i need to remove this... to start.

Answer tonight for the wire.

I need to prepare the good extractor tool for injector this week.

Click to expand...

That is really confusing. There do not seem to be enough wires in your C0573, but it is a bit difficult to see. Also, the page from the Electrical Library showing C0573 seems "wrong" (not unusual) as there is no pin1 and 2 x pin 11s!! Perhaps the expert @sierrafery can give an opinion here.

A noisy pump normally means air in the fuel. You have changed the pump. Injector seals failing will also cause a noisy pump as air gets into the fuel. There is a good write up on changing the injector seals here: http://www.discovery2.co.uk/Injector Seals.html

Many people use a long Allen key to remove the injectors.

Good luck!

First, i have air noise during pump initialisation cycle (like a dry pump, scream) when the first engine start failure : i have change filter, air bleed valve (new) and clean no return valve (small duck, a very little hole but clean) : less noise and 4 bar at regulator
Just after, i have test a brand new pump : no noise, no more air inside hose and always fast 4 bar at regulator

ok for allen key, i try

transpalette84 said:

First, i have air noise during pump initialisation cycle (like a dry pump, scream) when the first engine start failure ....

ok for allen key, i try

Click to expand...

That does sound like "air" past the injector seals. They are worth doing anyway. There are good examples of injector removal tools here, if you have not seen it already: https://www.landyzone.co.uk/land-rover/td5-injector-removal.329268/

Hi, unfortunately i dont understand too much from your first description but if the engine started well and ran before and just stopped then IMO the problem is not with that wiring bodge which i dont have any ideea what's doing... though seems that you replaced all the usual suspects which dosnt mean it's fixed.. you cant diagnose this without plugging in a compatible scanner(nanocom or similar) to see the rpm while cranking cos the crank sensor wiring used to have issues and as long as it's cranking with good fuel pressure at the FPR and no "fire" means that the ECU doesnt open the injectors... if it's manual try to bump start it without cranking on ignition cos there are cases when the startes motor disturbes the crank signal also measure the voltage on the battery while cranking and if it drops below 10.5V it will not start

thank you for your help
i have update the first post for better explanation !

transpalette84 said:

but still no start and just crank, no fuel = only starter
ECU = error crank high speed only, all injector "clic" during injector test
CKP = 190rpm, with another brand new CKP : same situation (and wire look ok)

Click to expand...

That's too low, it will hardly start below 250rpm while cranking and if the sensor and wiring are OK it's very possible that the starter disturbs the crank signal and this one usually comes with a voltage drop tooand no smell of diesel at the exhaust if it's that... if the injector copper washers are the problem it should start after a purge and smell at the exhaust while cranking

ok, I'm testing this evening after work with capacitor booster. I prefer it to be the fault of a too weak battery to end it, I could die of shame happily after that...

I agree with you regarding the injector seals, I have not found a single testimony in several Land Rover forums of a sudden breakdown with a seal defect. Always difficult to start with fuel or high oil level.

on the other hand, for the red wire, I would like to understand what this corresponds to

no change with another battery (12,5v + booster)
just installed rave

ok, with this wire (pin 2 on C0573), i have recover the starter.
and if i remove the glow plug relay, i have the error inside the ECU.
it's a by pass for "crank enable" with a locked BCU, confirmed by a guy.

for information, i have unpack my second BCU (in spare), read the eka, edit the EKA to a simple code, fully configure for my car all option, the same VIN like ECU and body, FOB and ECU learning security : no change

next step : swap the entire engine fuxe box ... if you have another idea !

transpalette84 said:

no change with another battery (12,5v + booster)

Click to expand...

The only relevant is the voltage WHILE CRANKING

transpalette84 said:

ok, with this wire (pin 2 on C0573), i have recover the starter.
and if i remove the glow plug relay, i have the error inside the ECU.
it's a by pass for "crank enable" with a locked BCU, confirmed by a guy.

Click to expand...

If C0573 -7 is grounded to make the starter work means that the vehicle is immobilised for some reason and just enabling the starter relay with that bodge would not make the engine start or run cos when it's immobilised beside disabling the starter the BCU locks the security code signal so the engine ECU is disabled too... unless there was an interruption on that starter relay coil's earth path, if it was in the fusebox earthing that wire would not have had any effect

i still didnt get if you can unlock with the fob or not? ... though for test set the BCU alarm option to "not fitted" and try then

When I installed the new BCU I had too weak a signal for the fob.
Since I changed the receiving module on the roof, i have a better signal and I added the original remote control and a new one without problem to open/close all door.
Now I have 100% success in the RF detection test with the nanocom, before I had to be close to the receiver with 20% success
I have recover the remote opening and close, the red light disappears on dashboard and ECU indicates IMMO OFF when I control it with nanocom.

I noticed that the driver door lock opens and closes with the mechanical key normally. But with the fob, it closes well but does not open while the 3 others are ok ?

I will check for the alarm but I think I have already tested this setting

What I don't understand is the link between the sudden locking of my first BCU, after disconnecting the battery, and since then the impossible start. I noticed when purchasing the car that the BCU was impossible to read/connect from ODB (I knew I had to read the EKA code and note it) unlike ABS or ECU but no starting problems. As I remember, I had the red LED flashing constantly during the return trip at night. But no starting problem.

I think I have two problems, the first of a mechanical type and it has been corrected (fuel circuit). This first problem happened before I touched anything on the car. So I didn't have a remote control and a IDM with broken flasher at this moment.

The second electronic type active since the battery disconnection and connector check of all module before clean my IDM to recover turn signal (before a full IDM change), I note the locking of the BCU (flash light when you connect the battery) and its replacement, during the mechanical work.

The seller told me he lost his unique key before my arrival, he collected a driver's door handle and a neiman with key from another discovery 2. He gave me the old original locks without key with the car

I think I have given all the details that I know

thank you for your help, I don't know how to thank you for the time spent ?

So, as long as now you can unlock with the fob and it reacts normally means that it's remobilised so the non starting issue is about that low rpm input...insist on that path:
1. rpm should be above 250
2. battery voltage while cranking above 10.5V
these are compulsory to start.

I installed a new starter and the engine started without problem.

The old one hardly works anymore, in my last tests it was almost completely dead.
I think I completed my original starter during my many starting attempts with the fuel problem and air cavitation in the pump.

Only that doesn't explain why I have to have pin 2 grounded in connector C0573 to be able to crank the starter.
I would like to understand the real problem to make it more reliable.

I tested two BCUs and IDMs with no difference.
Engine ECU should not intervene in the starter? I will still be able to test with a second ECU to be certain.

What do you recommend to start my search?

Thank you.

I'm glad it starts now, the starter was mentioned in my first reply then we were carried away with the discussion.

About C0573, first of all double check the connector view cos it should be about pin 7 not 2, a black/orange wire(second from left) cos this one is the switched ground from the BCU for immobilisation when that's the case, if the fob unlocks and the engine starts only by grounding that wire means that the wire coming from BCU's C0662 - 5 is interrupted and the remobilisation ground from BCU doesnt reach that connector or the BCU has a bad ground on that path but then it should have other issues too or if it was immobilised it should not start cos the security signal to the ECU is interrupted too, the ECU has nothing o do with starter operation, check continuity of that wire from BCU to fusebox, i cropped the relevant part:

I watch during the day.



Below, a zoom of my C0573 connector and its current modification... it is indeed number 7 and not number 2 because I looked at the description of the connector the wrong way.

Sorry, rookie mistake!

ok with my multimer between fusebox and bcu

other connector : ABS unit, a cutte wire here ?