Toledo TDI AFN: Error Code 01237 Troubleshooting

Hello fellow turbo-diesel enthusiasts,

I've been having a problem with my Seat Toledo 1L TDI with a 110hp AFN engine for several weeks.
90,000 km.
Unfortunately, I haven't found a suitable solution in the previous posts.
Coming from a Golf 1 diesel with 54 horsepower, I've already disassembled and repaired everything related to the diesel technology, including the injection pump and injectors. I'm quite familiar with this type of technology. I know how to adjust things like the fuel injection timing using a micrometer screw, etc.
Unfortunately, I haven't been able to find any detailed technical documentation for the new engines specifically related to my Toledo yet.
Now, my problem is:
Initially, I had it twice.
01237 - Fuel Shut-Off Valve (N109)
04-00 - Mechanical Failure
00575 - Intake manifold pressure.
17-10 - Control Difference - Intermittent
After reading and clearing the error codes, only error code 01237 appeared twice.

The entire process should be repeated every 3 to 5 days.
I don't have an explanation for the "Shut OFF Valve" error. If the valve is the high-pressure shut-off valve that I'm familiar with from older Bosch systems, then it should be okay; otherwise, the engine wouldn't be able to run. After the error appears, I sometimes experience the engine revving up excessively during startup, followed by a limp mode.

I operate my Toledo using up to 50% rapeseed oil without any modifications.

I also have another Toledo Magnus of the same configuration with 215,000 km and used in the same way. I haven't experienced that issue with it yet.
The Toledo, with 90,000 kilometers on the odometer, was previously registered in Bischofsgrün. This model shows clear signs of salt damage from winter use all over. It has a tow hitch.
The Toledo with 215,000 km was red, which means it's in a significantly better condition and runs like new.
Operate both vehicles very gently, with an average fuel consumption of 4-4.5 liters.

Does anyone have any ideas on where I should start here?

"There must obviously be an electrical cause that is generating this error. I can't find any mechanical reasons for it. Where can I find documentation for my Toledo about the electrical wiring?"

Regards,

Hubert.

01237 Fuel shut-off valve N109... Perform an actuator diagnosis to check if it is functioning.

Hello colleague,

Thanks for the tip, I already tried that. No luck. I've repeated the process again. Still no result. The frustrating thing is that the car is working fine right now.
Das Ventil hat nach Zündung an für ca. 3s Strom und schaltet dann ab. Beim Starten ist das dann wieder unter Strom. SEverything's fine so far.
Just to clarify, when the shut-off valve is de-energized, no fuel is pumped on the high-pressure side, right? Has anything changed in that regard compared to the old mechanical pumps?

My 50% rapeseed oil mixture shouldn't cause any problems there, right?
I will continue to monitor this.

See you later.
Regards,
Hubert.

Hi.

Ja, der N109 ist wie bei den alten Pumpen zum Abstellen im Hochdruckteil da, indem es die Fuellbohrung des HD-Kolben schliesst. Anbei die Grafik einer mech. ESP.


However, the TDI engine is shut down via the quantity control unit by simply setting it to zero. This was not possible with mechanical pumps because it would mean deactivating the idle speed regulator.

You can therefore remove the valve plug as a first aid measure and shouldn't notice any difference (unless you want to stop a malfunctioning quantity control system, in which case the only solution is to shut it down like in the good old days of mechanics: by disengaging the clutch and applying the brakes).

Now, the question is:
How can you perform an actuator diagnosis if the N109 shuts down the engine after 3 seconds because it no longer has power?

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hello Dieselmartin,

Thank you for the information. It's now clear that the shut-off valve is the same as before because the mechanics are still the same, as far as I can see.

Okay, I'm getting voltage at the valve when the ignition is on for about 5 seconds (it seems to be closer to 5 seconds than 3). Then it turns off again. This happens consistently and repeatedly. I assume that the control unit times this function when the engine isn't started.
Once I start it, the valve is under tension again. Then, of course, the motor will run.
I then assumed that was okay.
I've temporarily removed the valve and checked it. Everything seems to be fine. The engine hasn't stalled before either.!!!??? I've now experienced the limp-home mode again during a short trip, after starting with a brief run of the engine. After that, I measured everything again, and the voltage is still correct as before.

Is this behavior with the 5-speed transmission not normal? I'm experiencing the same issue with my second Toledo.
I don't have those problems with that one.

It looks like a tricky but probably very simple error, judging by how it's behaving.

Unfortunately, I don't have a wiring diagram for my Toledo cars, so I can't effectively troubleshoot them without spending an entire day disassembling everything.
"However, I can't detect any supply problems at the valve. I assume that everything should be fine otherwise, or the engine would stall or at least misfire if it were only a temporary issue. Otherwise, I wouldn't be able to drive in limp mode."

Regards,

Hubert.

Hello colleagues,

Today I drove to RGB, about 120 km each way. The Toledo was running perfectly. When I arrived at RGB, I had to stop briefly before driving into the parking area. I turned off the engine for a short time. When I restarted it, the engine started normally, but then went into limp mode again. I drove home in limp mode.
Zuhause hatte ich dann wieder Fehler 01237 und 00575. Error deleted.
Start the engine. Then, a constant error code 01237 appeared while the engine was idling normally.
That really annoyed me. First, I replaced the exhaust. Still in limp mode!
Hab die Karre dann zerlegt. Das Abstellventil nochmal raus. Spannung gemessen. Stelldiagnose durchgeführt. Kein Problem gefunden. Hab dann alle möglichen Stecker geöffnet und kontrolliert, Kontaktspray beträufelt. Zusassembled by hand.
Hab dann das R109 ausgebaut, zerlegt, kontrolliert. Alles ok. Kontaktspray auf die Steckzungen. Das gleiche bei den anderen Relais. Konnte aber kein offensichtliches Korrisionsproblem finden. Alles wieder zusammen gebaut. die Motorsteuerung ausgebaut. Die Massekontakte waren an der Verschraubung etwas korridiert. Stecker gelöst Kontaktspray. Da Ganze wieder zusammen. Hab dann alle möglichen Schlauchverbinder kontrolliert. Bei Zweifel etwas nachgesetzt. Motor wieder gestartet. Ka mistake!
Okay, let's do a test drive. Initially, it exhibited some strange behavior. When accelerating, there was only temporary power output, as if the turbocharger was cutting out. This would then disappear and reappear. I then pushed the car harder. At first, I couldn't reach the maximum RPM. The acceleration felt sluggish. After several acceleration runs from 20 to 120 km/h, everything seemed fine again. I could accelerate quickly to the maximum RPM, and the throttle response was as expected at every RPM. Afterwards, the error memory was empty.
There's one thing I haven't mentioned yet. The exhaust pipe had a hole just before the muffler for a few days. It was barely audible. But today, after the RGB ride, I replaced the entire exhaust system.

Could that be related?

First, the problem is gone again.

Hello,

I'm experiencing the same problem now. Were you able to resolve it?
Where is the R109 located? Is it a relay or a fuse?


Thank you very much.

2fast_driver

Hello everyone,

I have now permanently solved this problem...

The problem is caused by an electrical issue at the ground (GND) connection of the motor control unit.

A common problem in the automotive industry: All electrical connectors are now sealed against high-pressure cleaning, but not the grounding connections of the engine control unit or similar components. These are always exposed to the elements.

The ground connection located beneath the engine control unit is a copper wire with a galvanized ring terminal attached to a copper-plated steel screw on the vehicle's body.

A great electrochemical potential series. It works quite well under saline conditions. The whole problem only becomes apparent when everything is disassembled.

verschandeln everything thoroughly, then apply a good layer of grease to the threads, and everything will work properly again, and it will last.

Regards,

HL

Hello everyone!


"In my T3 bus with an aftermarket fuel injection system (AFN), I'm experiencing a lack of power (approximately half the normal power). The error memory indicates:"

01237 - Fuel shut-off valve (N109)
04-00 - Mechanical Failure

The error message appears after starting the engine when it's already warm.
When starting the engine with a cold start and after clearing any stored error codes, full power is available.

My suspicion falls on "spinning" MSG. But here are the facts first:

MSG: 028 906 021 JD (Bosch part number: 0 281 001 807) Engine installation: October-09, HA project.
Nothing has been modified or adjusted on my MSG (presumably referring to a specific device or system).

"Until last October (2013), it worked perfectly fine. Then, it started performing at only about half its capacity without any apparent issues."
Otherwise, any unusual observations might include things like: difficulty starting, erratic running, speed-dependent behavior, increased black smoke emissions, etc.

Reading the error memory often revealed:

01117 - Generator Terminal DF Load Signal.
27-00 - Implausible signal.

01237 - Fuel shut-off valve (N109)
04-00 - Mechanical Failure

00625 - Vehicle Speed Signal
27-00 - Implausible signal.

Some troubleshooting steps have been taken, including the use of:
Performance issues: Systematic troubleshooting with VCDS.
and the search query: "AFN power loss" -> 120 results.
"Insufficient AFN performance" -> 24 results.
"Lack of performance" -> 324 search results.
"Fuel shut-off valve"

The yellow preheating lamp is not working.
Inspection of: Mass Air Flow sensor (MAF), Exhaust Gas Recirculation (EGR) valve, Variable Turbine Geometry (VTG), Lambda Sensor (O2 sensor), Leak in the intake manifold, Boost pressure with a mechanical gauge, Catalytic converter blockage, ...?
Check the wiring harness for damage, and measure the resistance of individual cables.
ELAB extended, nothing suspicious found. Replaced with a resistor: no improvement.
Apply contact spray to the contacts of the MSG (Message Security Gateway).
The valve receives a 12V control signal when the engine is started.
Connect the main power cable of the MIG welder directly to the engine block.

Unfortunately, the issue of "01237 - Power shut-off valve - intermittent error" also yielded no results.


It turned out that the engine was running at full power when the error memory did not contain any errors.
01237 - Fuel Shut-Off Valve (N109)
04-00 - Mechanical Failure
shows and is started with a cold engine (after clearing the error memory).
It is sufficient to signal to the control unit that it is in a "cold" state via...
Coolant temperature sensor or a resistor with a value equivalent to approximately 50 degrees Celsius.


Logs of the engine operating parameters (MWB) were recorded from 0 to 21, under full load conditions at speeds of 2800-3100 RPM.
My table "Log_Vergleich_24feb14.xlsx" shows the minimum and maximum values according to "Target data from MWB Kaufmann VCDS".
and the maximum power values for the "full power" state and the maximum power consumption values for the "half power" state.


As far as I can tell so far, it's not clear what is causing the lack of performance in a warm-started engine, given the error code information.
01237 - Fuel Shut-Off Valve (N109)
04-00 - Mechanical Failure

Very rarely, it can also happen that only half the power is available even when there are no error codes stored or with the following error codes:
01117 - Generator Terminal DF Load Signal.
27-00 - Implausible signal.

00625 - Vehicle Speed Signal
27-00 - Implausible signal.
without
01237 - Fuel shut-off valve (N109)
04-00 - Mechanical Failure


The ELAB (N109) has remained unchanged since at least November 2009, and it functions correctly even without a seal on the piston.
It also doesn't have a blocking function.


My suspicion now falls on the engine control unit with the part number "028 906 021 JD (Bosch part number: 0 281 001 807)".

The results of the numerous log files are in the appendix: Log_Comparison_20240214.xlsx.
with engine operating temperatures between 0 and 20 degrees Celsius.
at full power.
and half power.
and according to the minimum and maximum values, "Target data for measurement block ranges for 4-cylinder engines.pdf" (Kaufmann VCDS diagnostics).

The main difference between full power and half power, in my opinion, is only the amount of fuel injected.

I would now like to ask for your help:

What are the suggestions?

Due to the difficult/complex procurement process for "028 906 021 JD (Bosch part number: 0 281 001 807)".
I would also like to inquire about a more common replacement part, as perhaps replacing it could resolve the frequent performance issues.


Sure, thanks in advance for your help.
Kerzinger.


P.S.
Since my previous T3 specialist in Munich/Grosshadern closed their workshop, I am now...
Looking for another reputable T3 workshop.

Quote:

01237 - Fuel Shut-Off Valve (N109) 04-00 - Mechanical malfunction. The ELAB (N109) has remained unchanged since at least November 2009, and it functions correctly even without a seal on the piston. It also doesn't have a blocking function.

Well, the failure of the broken N109 is being detected, and I don't understand why it hasn't been repaired.

Please check the pedal switch bits (clutch/brake) in the corresponding measurement block of the engine control unit. If the switches are misadjusted or defective, nothing will work.

Quote:

After the error appeared, I sometimes experienced the engine revving up too high during startup and then entering a limp mode.

Either the fuel injection pump is clogged/faulty (a mixture of 50% diesel is also too much in winter), or check the coolant temperature sensor in measurement block 7 of the engine control unit.
Assuming a very low coolant temperature, the engine control unit increases the idle speed; if the temperature is too high, the engine power is reduced.

Best regards, Rainer.

I will install a new N109 module and report on the results.


I understand that the N109, which has recently been occasionally displayed as having errors, is...
that the constantly open valve should not be the cause of the malfunction.
"Because this has been happening for years and hasn't caused any problems."
I didn't perform the test involving the replacement part because I didn't have a functioning N109, and it costs around €80 at VW/Audi.

After a new N109 (fuel shut-off valve) has been installed, complete with a locking bolt.
Does the AFN engine deliver full power even when starting with a warm (>80 degrees Celsius) engine?
and that without a single error message.

01237 - Fuel shut-off valve (N109)
04-00 - Mechanical Failure

The motor is now working perfectly again with the old electromagnet when the locking bolt is installed.

Hopefully, the motor will continue to function properly once the locking pin is installed.
I'm surprised that it worked fine for at least 4 years without the locking pin, and now it's unexpectedly missing.
Compare also: https://community.dieselschrauber.org/en/viewtopic.php?p=215859#215859

Here: A heartfelt thank you to Rainer for motivating me to get a new N109!


P.S.
What is the bit encoding for the pedal signals (clutch/brake)? Part number: MWB-06, Cruise Control.
As diesel fuel, I exclusively use diesel from gas stations.
Coolant temperature sensor functioning as expected.

Quote:

06,2, Brake pedal monitoring. 1xx - Brake light switch (F) closed. ; x1x - Brake pedal switch (F47) open. Clutch pedal switch (F36) open. 006,3, Speed control system. ; 1xxxxx - Clutch pedal depressed. ; x1xxxx - Brake pedal pressed. ; xx1xxx - Resume/Accelerate ; xxx1xx - Speed delay ; xxxx1x - GRA with memory ; xxxxx1 - GRA enabled. 006,4,Operating status ; 000 = Control unit with GRA function. ; 001 = GRA disabled. ; 002 = Accelerate ; 004 = Delay ; 008 = Resumption ; 016 = Brake pedal pressed. ; 032 = Maintain speed. ; 064 = ignore. ; 128 = ignore ; 255 = Control unit without GRA function

Thank you for the feedback!