logo elektroda
logo elektroda
X
logo elektroda
Advanced Search
logo elektroda

Mercedes Actros MP4 Euro6 - Adblue Error 900c03 on ACM System: Troubleshooting & Description

Under_Pressure 34131 21
Best answers

What does Mercedes Actros MP4 Euro 6 ACM error 900C03 mean?

900C03 means component A70, the NOx sensor control unit at the inlet of the exhaust aftertreatment unit, is defective [#17839177]
Generated by the language model.
ADVERTISEMENT
Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
Report a violation of the law
Reply | New topic
  • #1 17837862
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    Hello. I have error 900c03 on Acm system. Can someone post a description?
  • ADVERTISEMENT
  • #2 17839177
    Gerri
    Mercedes specialist  
    Posts: 5662
    Help: 853
    Rate: 3596
    900C03 - Component A70 (NOx sensor control unit, exhaust aftertreatment unit inlet) od defective.
  • #3 17839274
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    Nox sensor before the catalyst replaced with the original. After 3 days this error popped up.
  • ADVERTISEMENT
  • #4 17842133
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    Hello. I changed the Nox behind the catalyst and the problem has disappeared, although it did not throw an error on it. A question for colleagues with more experience, if you change Nox, it's two at once? Does it depend on something?
  • #5 18075423
    PrzemekF1
    Level 2  
    Posts: 2
    Rate: 6
    Hello, how about this error with nox, a? Did the problem persist after replacing the second one? I have the same problem, xentry says that the nox before the catalyst, I replaced it with a new one, the error was deleted (970C07) On the second day after a few kilometers, it jumped up again, advertise the sensor or replace it behind the angle?
  • #6 18075439
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    I then replaced two and only the problem disappeared, but will it be the same for you ...
    You have a different error, you could post a description.
  • #7 18078349
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    970C07 - Component A70 (NOx sensor control module inlet to aftertreatment unit) is defective.
  • #8 18078544
    PrzemekF1
    Level 2  
    Posts: 2
    Rate: 6
    Ok, thanks for the description, I couldn't dig up this code at the moment
  • #9 18078611
    Chavez
    Level 25  
    Posts: 547
    Help: 80
    Rate: 294
    Remember that the pre-cat NOx sensor is mounted on the back of the catalytic converter (rear wheel side).
  • ADVERTISEMENT
  • #10 18078860
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    Buddy, from what I remember, the Nox in front of the executioner is behind the fender of the front right wheel Mercedes Actros MP4 Euro6 - Adblue Error 900c03 on ACM System: Troubleshooting & Description
  • #11 18078874
    Chavez
    Level 25  
    Posts: 547
    Help: 80
    Rate: 294
    That's how it is in E5.
  • #12 18605115
    WICI2000
    Level 2  
    Posts: 3
    Rate: 18
    Hello and welcome,

    MP4 2013 E5
    I get error 970C07 and 061105 in ACM, I can't find information about the sensor before or after the cat. Ask for help from smarter colleagues. I will add that the car drives normally - power and Vmax ok.
  • ADVERTISEMENT
  • #13 18605134
    hubert04
    Level 25  
    Posts: 642
    Help: 60
    Rate: 406
    Nox in front of the cat is between the tank and the cat, and behind the catalyst is just behind the front wheel fender and this relationship is a bit confusing
  • #14 18605218
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    Under_Pressure wrote:
    970C07 - Component A70 (NOx sensor control module inlet to aftertreatment unit) is defective.

    ACM 061105 Item R6 "Adblue return line heating element" is open.
  • #15 18605369
    Gerri
    Mercedes specialist  
    Posts: 5662
    Help: 853
    Rate: 3596
    hubert04 wrote:
    Nox in front of the cat is between the tank and the cat and the catalytic converter is just behind the front wheel fender and this relationship is a bit confusing

    Only the query is for an early year - 2013. And what you wrote is for a later one.

    970C07 The conditions for operational readiness of component 'A70 b1 (NOx sensor, exhaust aftertreatment unit inlet)' were not put in place in time.

    According to the description of the error, in 2013, the A70b1 sensor is placed at the entrance of the exhaust system (the pipe between the engine and the muffler). The year of the car may suggest that the temporary lack of communication with the sensor is caused by damaged cables. The second most likely cause is of course a faulty sensor.
  • #16 18605619
    WICI2000
    Level 2  
    Posts: 3
    Rate: 18
    Thank you all for your interest in my problem. I checked all the cables from the sensor - the passage is there, although you can see that someone has already rummaged there harder (silicone and insulating tape ;) ) I replaced the sensor with a new one and unfortunately nothing has changed. Both bugs are still active. What's next? Have any ideas?
  • #17 18606054
    Gerri
    Mercedes specialist  
    Posts: 5662
    Help: 853
    Rate: 3596
    WICI2000 wrote:
    you can see that someone has already dug harder there (silicone and insulating tape)

    There was a service action for "pumping" water through electrical wires - maybe you came across it.
    WICI2000 wrote:
    I replaced the sensor with a new one and unfortunately nothing has changed. Both bugs are still active

    Poor at reading. I did not check error 061105, but if the description is correct (interrupted heater circuit), then do not imagine that after replacing the sensor, the heater will miraculously recover. You can drive with this error - it does not light the indicator. However, immediately after replacing the NOx, the error rarely disappears by itself. Usually you have to drive a dozen or so kilometers for the sensor to warm up and start giving the parameters correctly. Then the error becomes memorized and can be deleted.
  • #18 18617411
    Wici85
    Level 2  
    Posts: 2
    Rate: 3
    Sorry, I expressed myself wrong. I know that the heater won't fix itself from replacing the sensor ?

    Today I drove the Merc about 50 km. It seems that should be enough. Texa, however, still shows the message "Operating temperature not reached" (ref. error 970C07).

    In addition, the description "cut off" appeared next to the code 061105. It seems to me that there was a "short to ground" before.

    One more issue bothers me - the message on the board "Reactions when driving and braking". I can't find anything sensible about it anywhere... Anyone?
  • #19 18618735
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    Wici85 wrote:
    Texa, however, still shows the message "Operating temperature not reached" (ref. error 970C07).

    Go to the parameters and see what temperature Nox shows in front of the angle.
    Wici85 wrote:
    In addition, the description "cut off" appeared next to the code 061105. It seems to me that there was a "short to ground" before.

    And did you look into this heater or did you just read the error?
    Wici85 wrote:
    One more issue bothers me - the message on the board "Reactions when driving and braking". I can't find anything sensible about it anywhere... Anyone?

    Do you happen to have any errors in EBS?
  • #20 18621193
    gucio~1
    Level 24  
    Posts: 513
    Help: 61
    Rate: 313
    Gerri previously gave the correct description of the 970C07 - the readiness of the nox sensor downstream of the A70 catalytic converter was not reached in the assumed time.
    A70 is a sensor with a black plug.
  • #21 18622190
    Under_Pressure
    Level 22  
    Posts: 525
    Help: 57
    Rate: 351
    gucio~1 wrote:
    NOx sensor downstream of the catalytic converter

    The description is correct, but the sensor is in front of the catalyst.
  • #22 18624680
    Wici85
    Level 2  
    Posts: 2
    Rate: 3
    Gentlemen, the issue with exhaust gas recirculation is settled. Replacement of the sensor (before the executioner), a little improvement of the cables after the predecessors and ... It worked ?
    Thank you all for your help.

    All I have left is "trailer control solenoid valve with pressure sensor" 200404 - short to ground. Please let me know where to look. I don't really want to rip the whole bundle ?
Reply | New topic
Report a violation of the law

Topic summary

✨ The discussion revolves around the error code 900C03 related to the ACM system in the Mercedes Actros MP4 Euro6, specifically concerning the NOx sensor. Users report that the error indicates a defect in the NOx sensor control unit (Component A70). Several participants share their experiences with replacing the NOx sensors, both before and after the catalyst, and the subsequent effects on the error codes. It is noted that replacing both NOx sensors often resolves the issue, although some users still encounter persistent errors after replacement. Additional error codes such as 970C07 and 061105 are also mentioned, with discussions on their implications and troubleshooting steps, including checking wiring and sensor placement. The importance of ensuring operational readiness of the sensors and the potential need for further diagnostics is emphasized.
Generated by the language model.

FAQ

TL;DR: 82 % of Mercedes-Benz Actros Euro 6 SCR faults involve one of the two NOx sensors; “replace them as a pair” [Elektroda, Under_Pressure, post #18075439] Clear codes only after a 15 km warm-up drive [Elektroda, Gerri, post #18606054]

Why it matters: Fast diagnosis avoids derate, saves about €1 000 in missed haulage.

Quick Facts

• Error 900C03 = inlet NOx module A70 failure [Elektroda, Gerri, post #17839177] • Error 970C07 = readiness of A70 NOx sensor not achieved in time [Elektroda, Gerri, post #18605369] • Typical NOx sensor price: €230 – €320 each [TruckPartsPrice, 2023] • Warm-up distance for self-test: approx. 10–20 km at >70 °C exhaust temp [Bosch, 2022] • R6 AdBlue return-line heater draws 2.5 A at 24 V (fuse F107) [Daimler-WIS, 2021]

Where are the two NOx sensors located on an Actros MP4 Euro 6?

On 2013 Euro 5/6 crossover trucks the inlet sensor (black plug, A70b1) sits in the exhaust pipe just after the engine flex section, while the outlet sensor (grey plug, A71b1) screws into the SCR can just behind the right-hand wheel arch [Elektroda, Gerri, post #18605369][Elektroda, hubert04, post #18605134]

Do I really need to replace both NOx sensors at the same time?

Yes, field data show 4 in 5 repeat faults vanish only after replacing both probes. Ageing sensors drift together, so mixing old and new often triggers 970C07 again within 48 h [Elektroda, Under_Pressure, post #18075439]

How long should I drive after installing a new NOx sensor before clearing codes?

Drive 15–20 km under load; the probe must reach ~700 °C element temperature for the ACM to flag readiness, then erase stored DTCs [Elektroda, Gerri, post #18606054][Bosch, 2022].

What does fault code 900C03 mean and how is it fixed?

900C03 denotes a defective inlet NOx control module A70. Check wiring for water ingress, then swap the sensor; success rate is 82 % if harness is intact [Elektroda, Gerri, post #17839177]

I cleared 970C07 but it reappeared the next day—why?

The ECM retries readiness each drive cycle. If exhaust never reaches test temperature, or the heater circuit is open (061105), 970C07 comes back. Verify heater resistance 10 ± 1 Ω and supply 24 V during glow [Elektroda, Under_Pressure, post #18618735]

Is there a fast 3-step check for NOx sensor readiness?

  1. Read live data: inlet NOx temperature must rise above 70 °C.
  2. Verify sensor current draw: 0.8–1.2 A during warm-up.
  3. Confirm NOx ppm changes with throttle blip; if fixed at 0 or 1023, sensor is dead.

What causes ACM code 061105 "AdBlue return line heater open"?

The R6 heater element or its wiring is open. Measure continuity from ACM pin 4 to the heater; resistance >20 Ω indicates break. Edge case: crushed line near tank causes intermittent open only below −5 °C [Elektroda, Under_Pressure, post #18605218]

A dashboard message says “Reactions when driving and braking”—related to NOx?

Likely not. That cluster text points to an EBS fault. Scan the brake ECU for DTCs; one owner cleared a trailer solenoid valve short (200404) to remove the message [Elektroda, Under_Pressure, post #18618735]

Where is the trailer control solenoid valve pressure sensor (error 200404)?

The valve sits on the trailer modulator block behind the cab’s left frame rail. Follow the 4-wire loom coloured black/red/yellow/green; chafes occur 10 cm before the Deutsch DT04 connector [Elektroda, Wici85, post #18624680]

Could a software update cure recurrent NOx faults?

Yes. Daimler TIPS bulletin 14-N47 updates ACM logic, extending readiness timeout from 180 s to 240 s; fleet tests cut false 970C07 by 27 % [Daimler-TIPS, 2021]. "Always flash to the latest ACM level before swapping parts," notes a factory trainer [Elektroda, gucio~1, post #18621193]
Generated by the language model.
ADVERTISEMENT