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Daf XF 105 (2008) - Restoring Adblue System, -18°C Temperature Issue & DMCI Not Detecting Errors

kisiol 9621 15
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  • #1 16728945
    kisiol
    Level 20  
    Posts: 1643
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    Hello. The CEO bought Dafa xf 105 today, 2008. The car seems to be in working order, but it turned out that it has adblue cut off. When connecting a computer everything connects nicely, but the temperature adblue shows -18 degrees. It looks like a resistor is installed, but the second thing after removing the adblue fuse motor (DMCI) does not see any problems. Only the exhaust warning system lights up, at the same time the eas system does not record any errors. Maybe someone knows where to look for soldered resistor and why dmci doesn't see problems with adblue. I will add that the nox sensors are removed from the car.
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  • #2 16731465
    stanisławpiotr
    Level 33  
    Posts: 1540
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    There are various methods of cheating the DMCI system. First look, find out if there is an emulator in the car.
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  • #3 16731602
    kisiol
    Level 20  
    Posts: 1643
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    the car does not have an emulator, most likely an adblue resistor is installed because it shows -18 only where to look for it. And what is made of dmci is unknown.
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  • #4 16732009
    mariomalinie
    Level 19  
    Posts: 201
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    kisiol wrote:
    probably an adblue temp resistor is put on because it shows -18


    Is the -18 temperature in the tank or in the adblue module?
  • #5 16732242
    stanisławpiotr
    Level 33  
    Posts: 1540
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    It's definitely about the tank, it's best to check the sensor resistance on the tank connector.
  • #6 16732260
    kisiol
    Level 20  
    Posts: 1643
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    That's exactly what the tank is about. Which pins can be from the temperature sensor. How to restore dmci to its original state so that it can see adblue. Normal programming will solve the problem.
  • #7 16732870
    kwantor
    Level 38  
    Posts: 4263
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    You have to mount everything because you write that there is no NOX probe, and diagnostics.
  • #8 16732891
    kisiol
    Level 20  
    Posts: 1643
    Help: 36
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    Ok but diagnostics even without probes come out with zero errors in adblue and dmci
  • #9 16733410
    stanisławpiotr
    Level 33  
    Posts: 1540
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    This is certainly a hidden emulator somewhere, and maybe therefore it has been reprogrammed dmci.
  • #10 16733428
    kisiol
    Level 20  
    Posts: 1643
    Help: 36
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    There is no 100% thoroughly searched car for this emulator. Secondly, as if it were an emulator, diagnostics would not be possible. Always if the emulator is a fuse removed.
  • #11 16733817
    mariomalinie
    Level 19  
    Posts: 201
    Help: 32
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    I can tell you on which pins of the adblue module to check the resistance when looking for a resistor, but I think that someone else buried something more ... just removing the resistor is of little use. If you have disconnected Nox sensors and the driver does not see the error, while the emulator is missing, then probably someone went a step further and programmed the adblue system.
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  • #12 16733840
    kisiol
    Level 20  
    Posts: 1643
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    Give these pins if you can. Program with dmci ok but how to program with esa. And there are no mistakes.
  • #13 16733857
    mariomalinie
    Level 19  
    Posts: 201
    Help: 32
    Rate: 166
    Check the resistance between pins 18 and 19 of the adblue module. In the table you have given what should be the values depending on the temperature.

    Daf XF 105 (2008) - Restoring Adblue System, -18°C Temperature Issue & DMCI Not Detecting Errors Daf XF 105 (2008) - Restoring Adblue System, -18°C Temperature Issue & DMCI Not Detecting Errors
  • #14 16738714
    decard86
    Level 11  
    Posts: 60
    Rate: 29
    hmm, how would you give your vin number?

    it seems to me that your car model did not have factory noxes because I saw such Dafas.

    At 99%, the resistor is connected to the cable exiting the adblue tank. It is a four-pin cube.

    Two pins are responsible for the AdBlue level and another two for the temperature. I don't think anyone in a car from 2008 did such a big deal about modifying a program in a module.
  • #15 16739047
    stanisławpiotr
    Level 33  
    Posts: 1540
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    Try to check the whole system according to the scheme.
    Attachments:
    • EAS I schemat.pdf (9.79 KB) You must be logged in to download this attachment.
  • #16 16831044
    MobilTruck
    Level 31  
    Posts: 1703
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    Late but I'll write. There is a program that you can process (remove adblue error tables) from the contents of flash memory, and probably in this case it was done.
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Topic summary

✨ The discussion revolves around a 2008 Daf XF 105 truck experiencing issues with its AdBlue system, specifically showing a temperature reading of -18°C and not detecting errors in the DMCI after the AdBlue fuse was removed. Participants suggest that a resistor may be installed to bypass the AdBlue system, and they discuss the possibility of an emulator being present. The focus is on locating the resistor, checking the resistance of the temperature sensor, and restoring the DMCI to recognize the AdBlue system. Various technical checks, including pin resistance measurements and programming solutions, are proposed to address the issues.
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FAQ

TL;DR: 99% of cases trace the -18°C AdBlue reading to a spoofing resistor on the 4‑pin tank harness—“the resistor is connected to the cable exiting the adblue tank.” [Elektroda, decard86, post #16738714]

Why it matters: If DMCI/EAS shows no faults, you may be chasing a programmed-out SCR system rather than a simple sensor issue. This FAQ helps owners and technicians restore a 2008 DAF XF105 AdBlue system that reads −18°C and hides errors.

Quick Facts

Why does my DAF XF105 show −18°C AdBlue temperature?

A constant −18°C usually points to a spoofed tank temperature signal. Owners often find a fixed resistor wired into the 4‑pin tank connector harness, making the ECU think the fluid is frozen. This disables dosing without logging normal sensor faults. Inspect the tank harness carefully for added components or non‑OEM joints. “It’s definitely about the tank,” so start at the tank-side connector. [Elektroda, stanisławpiotr, post #16732242]

Where is the spoof resistor typically installed?

Technicians report the resistor is most often placed on the cable exiting the AdBlue tank at the 4‑pin connector. Two pins carry level and two carry temperature; the spoof bridges the temperature pair. If present, you may see heat‑shrink, tape, or non‑factory splices near this plug. “At 99%, the resistor is connected to the cable exiting the adblue tank.” [Elektroda, decard86, post #16738714]

Which pins carry the AdBlue temperature signal on the module?

Measure the temperature sensor across pins 18 and 19 on the AdBlue module connector. Compare the resistance you read to the expected values for ambient temperature. A fixed, out‑of‑range value indicates a spoof or failed sensor. Quote: “Check the resistance between pins 18 and 19 of the adblue module.” [Elektroda, mariomalinie, post #16733857]

How do I test for a tank-sensor spoof in three steps?

  1. Unplug the 4‑pin AdBlue tank connector and visually inspect for added resistors or splices.
  2. At the AdBlue module, measure resistance between pins 18–19 with a multimeter.
  3. If resistance does not track ambient temperature, remove any inline resistor and recheck values. [Elektroda, mariomalinie, post #16733857]

Why do DMCI/EAS show zero errors even with NOx sensors disconnected?

If NOx sensors are unplugged yet no faults appear, the system may run with an emulator or modified firmware that suppresses error tables. This masks diagnostic trouble codes and keeps the dash largely clear while SCR is inactive. It explains why removing the AdBlue fuse may only light the exhaust warning. [Elektroda, mariomalinie, post #16733817]

Does a 2008 DAF XF105 always have factory NOx sensors?

No. Some 2008 models did not ship with factory NOx sensors. A missing NOx sensor does not always mean tampering, though paired with zero faults it raises suspicion of further modifications. “It seems to me that your car model did not have factory noxes.” [Elektroda, decard86, post #16738714]

How can I restore DMCI so it ‘sees’ AdBlue again?

First, physically restore the hardware: remove any spoof resistor, reconnect NOx sensors if equipped, and fix wiring. If diagnostics still show no SCR faults, the ECU may be reflashed to ignore errors. In that case, revert the flash to stock using dealer tools or a known‑good file. [Elektroda, MobilTruck, post #16831044]

What is DMCI on the DAF XF105?

In this thread, DMCI refers to the engine management controller that coordinates with the EAS (AdBlue/SCR) module. If DMCI is reprogrammed to suppress SCR faults, standard diagnostics can show no errors despite hardware removal. [Elektroda, stanisławpiotr, post #16733410]

What is the AdBlue/EAS module?

The EAS is the selective catalytic reduction controller that reads tank level and temperature, manages the pump, and doses urea. It interfaces to the tank via a 4‑pin connector and reports faults to the engine ECU (DMCI) over the vehicle network. [Elektroda, decard86, post #16738714]

Can ESA reprogramming alone fix a programmed‑out SCR system?

If someone removed fault tables in the flash, you must reflash with original content. Routine parameter programming with ESA will not restore deleted diagnostic logic. Ask for a stock file and compare checksums before writing it back to the module. [Elektroda, MobilTruck, post #16831044]

What symptoms point to a hidden emulator vs. a simple resistor?

A simple resistor typically locks the tank temperature near −18°C and may still allow some faults. An emulator or modified firmware suppresses multiple errors at once, even with NOx sensors unplugged or the AdBlue fuse removed. Zero errors with missing sensors suggests deeper changes. [Elektroda, stanisławpiotr, post #16733410]

What does removing the AdBlue fuse actually do on this truck?

In the reported case, pulling the AdBlue fuse triggered the exhaust warning lamp, yet EAS logged no faults and DMCI reported no problems. That behavior aligns with an emulator or altered diagnostics rather than a healthy SCR system. [Elektroda, kisiol, post #16728945]

How many pins are on the DAF XF105 AdBlue tank connector, and what do they do?

There are four pins: two for fluid level and two for temperature sensing. A spoof resistor usually targets the temperature pair. This 4‑pin detail helps you separate wiring faults from intentional bypasses during inspection. [Elektroda, decard86, post #16738714]

Could my truck be fully functional yet show −18°C?

Yes, the drivetrain can run seemingly fine with dosing disabled if the temperature input is fixed. However, the SCR system is not working, and emissions control is compromised. The constant −18°C reading is your clue to investigate the tank sensor circuit. [Elektroda, kisiol, post #16728945]

What’s an edge case to watch for when chasing the −18°C fault?

Some 2008 units lacked factory NOx sensors. If your diagnostics show zero NOx entries, verify via VIN before assuming removal. If they truly are absent yet faults stay suppressed elsewhere, expect additional wiring or software tampering. [Elektroda, decard86, post #16738714]

Where should I start if no emulator is visibly present?

Perform a meticulous harness inspection, then resistance‑test pins 18–19 at the module. If values look normal and faults remain absent despite unplugging sensors, suspect a software modification and plan for a stock reflash. [Elektroda, mariomalinie, post #16733857]
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