Depths of the limp mode p1211 & p0251

[Koraru]

Hey, I know there is many other posts on this, yet I've been in this battle now for almost 3 years and probably tried everything on the list.

The subject is a 2004 2.0tdci transit ambulance which they fitted with a HJBB engine for her retirement after which I converted her for a camper.

Drove for many years without major problems, the limp mode occurred once or twice but never became a thing.


Almost 3 years ago driving up a very steep mountain, I started to hear something like misfires, rattling, loss of power and dive in to limp mode.
Main codes shown were p1211 p0251
I clear them all seems fine until then next one limp mode.
Since then the car is throwing up the limp mode driving with in 5 min and even stationary when releasing the accelerator abruptly from 3000rpm, the gauge lands on the bottom and then chokes down lower firing of the limp mode.
Sometimes I can do it 20x and it seems fine and sometimes it's a direct stall.

At this stage I:
Changed accelerator pedal
Checked all the fuel lines, tank..
Changed the diesel filter
Fitted new delphi injectors
New Valve on the delphi fuel rail
New delphi pump with all valves and sensors
New turbo
New map/maf sensors
Checked all the air pipes
New Crank shaft sensor
Cleaned the egr
Checked all the ground cables.
Checked the clocks for cold connections.
Probably a few more things I don't remember now.


What did I miss ?

Meanwhile my Canarian mechanic stripped the old ambulance electrics installation, as my battery kept getting slowly drained and is now convinced that it is an electrical problem that fires up the codes and wants me to get a new CPU to do a clone of the computer..

Other strange things happening like
The main cooling ventilator never worked, changed engine temp sensor, relay and thermostat. only Works if i short it.
Headlights turn on when I turn the ignition and the controller is off position.
The imoblizer lately also started to mess around.

I'm thinking maybe the mechanic messed up some connection?
Or could it all be signs of a faulty CPU for real ?

Maybe someone wants to come for a holiday to Tenerife and help me rule this out?
Its been so long and frustrating.. yet it feels like it makes no sense to give up at this stage as all is practically new. If it wasn't my camper maybe I would not be so sentimental.

[knobby1]

Hey, I know there is many other posts on this, yet I've been in this battle now for almost 3 years and probably tried everything on the list.

The subject is a 2004 2.0tdci transit ambulance which they fitted with a HJBB engine for her retirement after which I converted her for a camper.

Drove for many years without major problems, the limp mode occurred once or twice but never became a thing.


Almost 3 years ago driving up a very steep mountain, I started to hear something like misfires, rattling, loss of power and dive in to limp mode.
Main codes shown were p1211 p0251
I clear them all seems fine until then next one limp mode.
Since then the car is throwing up the limp mode driving with in 5 min and even stationary when releasing the accelerator abruptly from 3000rpm, the gauge lands on the bottom and then chokes down lower firing of the limp mode.
Sometimes I can do it 20x and it seems fine and sometimes it's a direct stall.

At this stage I:
Changed accelerator pedal
Checked all the fuel lines, tank..
Changed the diesel filter
Fitted new delphi injectors
New Valve on the delphi fuel rail
New delphi pump with all valves and sensors
New turbo
New map/maf sensors
Checked all the air pipes
New Crank shaft sensor
Cleaned the egr
Checked all the ground cables.
Checked the clocks for cold connections.
Probably a few more things I don't remember now.


What did I miss ?

Meanwhile my Canarian mechanic stripped the old ambulance electrics installation, as my battery kept getting slowly drained and is now convinced that it is an electrical problem that fires up the codes and wants me to get a new CPU to do a clone of the computer..

Other strange things happening like
The main cooling ventilator never worked, changed engine temp sensor, relay and thermostat. only Works if i short it.
Headlights turn on when I turn the ignition and the controller is off position.
The imoblizer lately also started to mess around.

I'm thinking maybe the mechanic messed up some connection?
Or could it all be signs of a faulty CPU for real ?

Maybe someone wants to come for a holiday to Tenerife and help me rule this out?
Its been so long and frustrating.. yet it feels like it makes no sense to give up at this stage as all is practically new. If it wasn't my camper maybe I would not be so sentimental.

Mk6 TDCi's are well known for having a fragile fuel system...one of our members, "Ned" battled with his for a long time. Both the P1211 and P0251 codes still point to a fault in the fuel metering system. Were the codes erased after all the work or do they just pop up regardsless. Could indeed be a wiring issue, poorly earth or broken wiring somewhere in the system.

Lord Knobrot

[Koraru]

Hey, thanks for the reply I manage to erase the fault codes every time. Untill the next coil comes up and the engine shut down the codes come back..

I was reading today about the ks sensor.
Would a faulty ks sensor could result it giving these codes

[knobby1]

Hey, thanks for the reply I manage to erase the fault codes every time. Untill the next coil comes up and the engine shut down the codes come back..

I was reading today about the ks sensor.
Would a faulty ks sensor could result it giving these codes

What's a ks sensor..??

Lord Knobrot

[Koraru]

The knock sensor as I understood its responsible for listening to the motor and helping the cpu to apply the right combustion mix, altough I did not get an error code pointing to him, altough I heard scenarios of the code not coming up even when the sensor was disconnected for some tdci members.

[Koraru]

Well I've checked the knock sensor, next.. I went back ti the fuel clear pipe check for air.. all seemed fine until a big bubble of air came through maybe 2 or 3 in a space of a minute... here could lie the problem..

I've noticed when I remove the hose of supply of diesel for the pump I can hear the diesel rushing back towards the filter

I'm wondering if there is a one way valve inside of the tank for the supply of diesel that maybe gave in ?

[Koraru]

Chapter later ,
I've done more fuel tests directly from a fuel canister and little filter to the high pressure pump and the car behaves exactly the same stalls with the limp mode appearing. At this stage I really don't know where to look any more.. is there any way to test the computer of the car for malfunction?

[knobby1]

Chapter later ,
I've done more fuel tests directly from a fuel canister and little filter to the high pressure pump and the car behaves exactly the same stalls with the limp mode appearing. At this stage I really don't know where to look any more.. is there any way to test the computer of the car for malfunction?

Won't sually be the PCM...they rarely fail.

I'd be popping the fuel filter off and cutting it open....and checking for metal particles....this indicates the fuel pump has probably failed....fairly common on the Mk6 TDCi's unfortunately.

Lord Knobrot

[Koraru]

Well at this point I've changed all four injectors, sensors and the high pressure pump flushed the system and fitted with a new diesel filter, and the problem continues as if nothing was changed which is why I start to think the problem lies in the Electrics .. next month I should arrive to change the ECU and I'll post some updates.

[Stevelien]

After replacing almost the same thing as your Transit, I addressed the following issues, which now prevent it from going into limp mode:

1. I removed the diesel particulate filter after the catalytic converter and cleaned it (in reverse) with Mr. Muscle oven cleaner and a pressure washer. It's an old-school diesel particulate filter without regeneration, so it gets clogged with diesel soot. It looks like an intermediate silencer, but it isn't. You can just remove it; it's the first part after the catalytic converter. I'm sure your HBJJ Mondeo engine also had this diesel particulate filter from the factory in 2004. So there are no sensors or hoses on it, just like there are no sensors on the catalytic converter. If it's clogged, you get a strange turbo pressure buildup via the EGR, which your MAF sensor after the intercooler reacts to by throwing it into limp mode. It's essentially too clogged with diesel soot after all those years and kilometers. I've checked with Ford Netherlands, and you can't buy a new one anymore, but as mentioned, it's easy to clean yourself. A dutch Transit 2.0tdci Mondeo exchange engine owner in a 2003 Transit had the same with it and it was his solution also. Some forum mebers deny yhe existence of a particulate filter in a 2003/2004 Ford engine but is a true particulate first generation filter.
2. Cap the EGR valve with a blanking sheet. It's vacuum-controlled, so you don't need to write it to the ECU. This will prevent it from leaking even after you've cleaned it.
Even if it's cleaned, it can cause strange errors in pressure buildup. Blanking plates are available on eBay, among other places. Be careful not to buy one for the 2.2d engine, which came later, as they have different dimensions. Google "Ford 2.0tdci 2003/2004 FIFA" or "Jaguar X-Type 2.0d" EGR blanking plate.
3. Try turning the diesel filter pollution meter upside down, if one is also installed on this HBJJ engine, because it draws in water from under the hood during and after rain. It's a red-yellow, transparent piece of plastic with a black knob and a piston inside it that measures the vacuum after the oil filter. In the factory-installed position, water falls on it and (especially when testing it) sucks water into the diesel line leading to the pump. You can easily turn it 180 degrees on the rubber hose. I discovered this because I also kept experiencing malfunctions during and after heavy rainfall driving or parked.
4 From your story, I gather you've installed four new Delphi injectors. I really hope they're really new, because some companies perform shoddy overhauls with Ali parts that don't work properly. I bought a "brand-new" injector from France that didn't work properly and after opening I discoverd these wrong Ali parts. I also bought a reconditioned one from Germany that was partially reconditioned, without any replacement parts from Noozle. Now I've installed four brand-new Delphi injectors. A good set is currently available on eBay in Italy for a reasonable price of €200 each; these are 100% factory-new.
4 check all your relay and fuse contacts.
5 New replaced Turbo I read so no sticking vanes I assume, often also one of the causes.But check your vacuum line(s) to the actuator for damage.

Good luck, my 2.0TDCI engine runs like a charm now. If the above does not help, an damaged electric wire(s) can be the cause...

[knobby1]

After replacing almost the same thing as your Transit, I addressed the following issues, which now prevent it from going into limp mode:

1. I removed the diesel particulate filter after the catalytic converter and cleaned it (in reverse) with Mr. Muscle oven cleaner and a pressure washer. It's an old-school diesel particulate filter without regeneration, so it gets clogged with diesel soot. It looks like an intermediate silencer, but it isn't. You can just remove it; it's the first part after the catalytic converter. I'm sure your HBJJ Mondeo engine also had this diesel particulate filter from the factory in 2004. So there are no sensors or hoses on it, just like there are no sensors on the catalytic converter. If it's clogged, you get a strange turbo pressure buildup via the EGR, which your MAF sensor after the intercooler reacts to by throwing it into limp mode. It's essentially too clogged with diesel soot after all those years and kilometers. I've checked with Ford Netherlands, and you can't buy a new one anymore, but as mentioned, it's easy to clean yourself. A dutch Transit 2.0tdci Mondeo exchange engine owner in a 2003 Transit had the same with it and it was his solution also. Some forum mebers deny yhe existence of a particulate filter in a 2003/2004 Ford engine but is a true particulate first generation filter.
2. Cap the EGR valve with a blanking sheet. It's vacuum-controlled, so you don't need to write it to the ECU. This will prevent it from leaking even after you've cleaned it.
Even if it's cleaned, it can cause strange errors in pressure buildup. Blanking plates are available on eBay, among other places. Be careful not to buy one for the 2.2d engine, which came later, as they have different dimensions. Google "Ford 2.0tdci 2003/2004 FIFA" or "Jaguar X-Type 2.0d" EGR blanking plate.
3. Try turning the diesel filter pollution meter upside down, if one is also installed on this HBJJ engine, because it draws in water from under the hood during and after rain. It's a red-yellow, transparent piece of plastic with a black knob and a piston inside it that measures the vacuum after the oil filter. In the factory-installed position, water falls on it and (especially when testing it) sucks water into the diesel line leading to the pump. You can easily turn it 180 degrees on the rubber hose. I discovered this because I also kept experiencing malfunctions during and after heavy rainfall driving or parked.
4 From your story, I gather you've installed four new Delphi injectors. I really hope they're really new, because some companies perform shoddy overhauls with Ali parts that don't work properly. I bought a "brand-new" injector from France that didn't work properly and after opening I discoverd these wrong Ali parts. I also bought a reconditioned one from Germany that was partially reconditioned, without any replacement parts from Noozle. Now I've installed four brand-new Delphi injectors. A good set is currently available on eBay in Italy for a reasonable price of €200 each; these are 100% factory-new.
4 check all your relay and fuse contacts.
5 New replaced Turbo I read so no sticking vanes I assume, often also one of the causes.But check your vacuum line(s) to the actuator for damage.

Good luck, my 2.0TDCI engine runs like a charm now. If the above does not help, an damaged electric wire(s) can be the cause...

He has a Mk6 TDCi Euro-3....He doesn't have a DPF...why you're suggesting how he can fix his DPF is beyond me.

Lord Knobrot

[Stevelien]

As mentioned, my Transit mk6 2.0TDCI from 06/2003 had a first-generation passieve particulate filter in the EU at the time. I removed the filter and cleaned it myself, and it's factory-installed also at EU Mondeo’s from that time. It is like all other particulate filters from other cars that time without a regeneration function. It works in chemical conjunction with the catalytic converter mounted in front of it. When I have more time, I'll explain it and add some photos for down under Lord. It's also easy to find on Google if you use the EU as a starting point, starting in 2003. The filter has only small channels for collecting soot particles, called passieve regeneration. Because this owner lives in Tenerife and is part of the EU he probably has an EU spec engine and Transit exhaust system. Many diesel vehicles that met Euro 3 standards in 2003 were already equipped with them, as Fiat and Mercedes, for example, did in the EU. This was a voluntary action by the manufacturer.

[metalworker0]

Because of the date - so does this mean possibly that you don't need it, to get through the MOT, can you remove it, ad leave it that way.

all the best.mark

[wojciech]

2. Cap the EGR valve with a blanking sheet. It's vacuum-controlled, so you don't need to write it to the ECU. This will prevent it from leaking even after you've cleaned it.
Even if it's cleaned, it can cause strange errors in pressure buildup. Blanking plates are available on eBay, among other places. Be careful not to buy one for the 2.2d engine, which came later, as they have different dimensions. Google "Ford 2.0tdci 2003/2004 FIFA" or "Jaguar X-Type 2.0d" EGR blanking plate.
.

The Transit Mk6 TDCi has an EGR valve without a position sensor, meaning the OCM can't detect the valve's position.
All other Ford models with the Delphi system have an EGR V with position sensor - the Transit is the exception. Therefore, there's no need to seal the exhaust pipe with a plate; simply disconnect the vacuum line controlling the valve. The EGR valve will then remain permanently closed—forever and ever. A five-minute job. However, the disconnected vacuum line must be tied off to prevent the vacuum system from sucking in false air.
----------------------------------
Generally, your problem is related to the injection system – with a 99% probability.
Have you performed a leak test on the injectors? Are you sure they are original, new, or rebuilt with genuine Delphi parts (valves and nozzles). The same applies to the high-pressure pump. There are plenty of poor substitutes on the market - repairs with such parts are usually a big failure.
Are the turbocharger and RGR vacuum controls interchangeable? Is the turbocharger wastegate working properly?
-----------------------------------
Do you have AC? Do the fans run when the AC is on? If so, and if the engine isn't overheating, then a non-working radiator fan isn't the problem

[Koraru]

WhatsApp Image 2026-02-04 at 18.11.14.jpeg

After replacing almost the same thing as your Transit, I addressed the following issues, which now prevent it from going into limp mode:

1. I removed the diesel particulate filter after the catalytic converter and cleaned it (in reverse) with Mr. Muscle oven cleaner and a pressure washer. It's an old-school diesel particulate filter without regeneration, so it gets clogged with diesel soot. It looks like an intermediate silencer, but it isn't. You can just remove it; it's the first part after the catalytic converter. I'm sure your HBJJ Mondeo engine also had this diesel particulate filter from the factory in 2004. So there are no sensors or hoses on it, just like there are no sensors on the catalytic converter. If it's clogged, you get a strange turbo pressure buildup via the EGR, which your MAF sensor after the intercooler reacts to by throwing it into limp mode. It's essentially too clogged with diesel soot after all those years and kilometers. I've checked with Ford Netherlands, and you can't buy a new one anymore, but as mentioned, it's easy to clean yourself. A dutch Transit 2.0tdci Mondeo exchange engine owner in a 2003 Transit had the same with it and it was his solution also. Some forum mebers deny yhe existence of a particulate filter in a 2003/2004 Ford engine but is a true particulate first generation filter.
2. Cap the EGR valve with a blanking sheet. It's vacuum-controlled, so you don't need to write it to the ECU. This will prevent it from leaking even after you've cleaned it.
Even if it's cleaned, it can cause strange errors in pressure buildup. Blanking plates are available on eBay, among other places. Be careful not to buy one for the 2.2d engine, which came later, as they have different dimensions. Google "Ford 2.0tdci 2003/2004 FIFA" or "Jaguar X-Type 2.0d" EGR blanking plate.
3. Try turning the diesel filter pollution meter upside down, if one is also installed on this HBJJ engine, because it draws in water from under the hood during and after rain. It's a red-yellow, transparent piece of plastic with a black knob and a piston inside it that measures the vacuum after the oil filter. In the factory-installed position, water falls on it and (especially when testing it) sucks water into the diesel line leading to the pump. You can easily turn it 180 degrees on the rubber hose. I discovered this because I also kept experiencing malfunctions during and after heavy rainfall driving or parked.
4 From your story, I gather you've installed four new Delphi injectors. I really hope they're really new, because some companies perform shoddy overhauls with Ali parts that don't work properly. I bought a "brand-new" injector from France that didn't work properly and after opening I discoverd these wrong Ali parts. I also bought a reconditioned one from Germany that was partially reconditioned, without any replacement parts from Noozle. Now I've installed four brand-new Delphi injectors. A good set is currently available on eBay in Italy for a reasonable price of €200 each; these are 100% factory-new.
4 check all your relay and fuse contacts.
5 New replaced Turbo I read so no sticking vanes I assume, often also one of the causes.But check your vacuum line(s) to the actuator for damage.

Good luck, my 2.0TDCI engine runs like a charm now. If the above does not help, an damaged electric wire(s) can be the cause...

Hey its been a while but I'm back trying to find solutions.
1. I did not find the diesel particulate filter that you mentioned before, I did disconnect the catalytic converter to see if that would change anything but unfortunately the engine continues to act the same and entering limp mode.
2.The EGR has been capped since I remember
3. I'm not sure what you mean by the diesel filter pollution meter, if you are talking about some little piece attached to the fuel filter head I don't have that in my version.
4. Ive checked all relay and fuse contacts I've went through all the ground connections and studied the harness and all the plugs..
5. Ive checked all the vacum lines and turbo/ air hoes with water and soap solution before as well.


I also experience other electrical problems like the stand by head lights staying on when I turn the key even if the headlights are off, (making me want to take out the whole harness and really go through it wire by wire..)

I Got the Forscan installed and read the codes again hoping to find something more.
P0623 - Generator lamp circuit ( since I bought the van the battery light signal has always been on the dashboard)
P1211 - Open TP sensor circuit
P0251- Injector pump fuel metering control malfunction
B2477 - Module Configuration Failure (The van was an ambulance and I had a "mechanic" help me to strip away all the old ambulance electronics and fuses panel, thinking maybe the problem lied there somewhere, I guess he disconnected the alarm device as well)

After running some tests also these came up,
B2242 Rear Cargo Door Unlock Circuit Open
B1312 Lamp Headlamp Input Circuit Short To Battery (I guess this one would explain the headlights going funny, yet Ive the wiring and couldn't find anything)
I sourced a CPU from a scrap yard that is the same model together with the ignition and immoblizer to try and swap with mine to cancel out the possibility that my CPU is maybe just fried. (maybe striping to check the full harness before that could be useful).