NOx problem on Volvo FMX500 : ACM out of order, what solutions?
Faults found on this Volvo FMX
The Volvo FMX 500 Euro 6 has several faults related to the AdBlue system and NOx sensors. Code P20B113 indicates an open circuit problem with the reductant heater control valve. Check wiring, connectors and test valve. Code P26E711 indicates a short to ground in the "D" actuator power supply circuit. Inspect wiring, test actuator and replace if necessary. Code U02A200 indicates loss of communication with the reducer quality module. Check connections, wiring and test module. Codes U029D00 and U029E00 indicate loss of communication with NOx sensors A and B. It is crucial to check the wiring and connectors, and to test the sensors.
After several hours of investigation at a garage, it was diagnosed that some sensors and the ACM control unit were faulty and no longer transmitting information. Two possible solutions: replace the ACM and the faulty components, or remove the system altogether (and possibly resell the truck for export), since they don't need adblue according to their standards.
The consequences of such defects on the vehicle will result in a short-term restriction of the truck's total power (reduced torque in 4h...), as well as a maximum speed of 20km/h.
The solution : Deletion of the Adblue FAP and EGR functions and deactivation of the ACM ECU.
We reprogram the ACM module to disable these functions. This eliminates AdBlue errors and avoids the performance restrictions associated with these faults. This operation requires the use of specific diagnostic tools to access the ACM. We reprogram the ECU, disabling AdBlue functionality and deleting fault codes. Once the reprogramming is complete, we check that all fault codes have been erased and that the vehicle is operating correctly without restrictions. This method ensures a lasting solution to AdBlue-related problems on the Volvo FMX 500 Euro 6.
Abolishing adblue, FAP and EGR for foreigners: Yes, but physically too.
When we deactivate the after-treatment device electronically on a Volvo FMX 500 Euro 6, there are several essential steps to be carried out physically on the vehicle:
- Empty the FAP :
- Remove the vehicle's particulate filter (DPF).
- Break the ceramic inside the FAP to empty it completely.
- Refit the empty FAP on the vehicle.
- Locking the EGR :
- Locate the EGR (exhaust gas recirculation) valve.
- Install an EGR lockout kit to block the flow of gas.
- Check the seal for leaks.
- Disconnect AdBlue pump :
- Identify the AdBlue pump located near the AdBlue tank.
- Disconnect the electrical connectors from the AdBlue pump.
- Check that the AdBlue pump is no longer running and that no electrical signal is passing through.
These physical actions complement electronic reprogramming by ensuring that the aftertreatment device is completely deactivated. They prevent any malfunctions or error reports linked to the AdBlue, EGR and FAP systems on the vehicle.
Disable ACM and other parameters so that CAN errors between ACM and EMS do not occur
Deactivating the ACM (Aftertreatment Control Module) offers a number of important advantages for preventing errors on the CAN network and ensuring smooth vehicle operation. By deactivating the ACM, errors associated with the aftertreatment system, such as AdBlue faults and NOx sensors, are no longer detected and reported on the CAN network. This prevents the transmission of error messages between the vehicle's various control modules, and eliminates degraded modes where the vehicle automatically reduces its performance to protect the engine and emission system. As a result, CAN errors no longer cause these degraded modes, allowing the vehicle to operate normally without performance limitations. CAN errors often require frequent diagnosis and intervention to resolve.
The photo below shows that after our intervention, there are no more faults in the ACM (since OFF) or in the EMS (motor control module).
We hope our article has helped you in your search. If you have any questions, please don't hesitate to contact us. You can also consult our other operations on Volvo Euro 6
