Adblue fault on Hydrema MX16 - Diagnosis, removal and engine optimization Cummins

Construction machines like the Hydrema MX16, equipped with the Cummins QSB 4.5 engine, frequently experience malfunctions related to the AdBlue system. These faults can lead to machine stoppages, power loss and a significant drop in productivity. By reprogramming the system using Calterm software, it is possible to completely deactivate the AdBlue system and restore optimal operation.

By modifying the parameters of the CM2350 ECU, we set up a more stable configuration, with no impact on the mechanics, while eliminating persistent fault codes. The result: a more reliable motor, with no warning lights, and restored performance on site.

Hydrema MX16 emission control system fault analysis

Advanced electronic diagnostics are essential before any intervention. Despite the replacement of several components, many users find recurring faults that cannot be permanently corrected without complete removal of the system.

• 6597: SCR (AdBlue) cleaning interrupted due to timeout. Often linked to an inactive catalyst or poor ACM control.
• 3251 / 3258: Catalyst inlet or outlet temperature above standard - may lead to DOC degradation.
• 3314 / 4533 : Excessive voltage or short-circuit to high source on temperature sensors. Wrong reading resulting in erroneous calculations.
• 5392: Intelligent module faulty - prevents correct processing of SCR critical temperatures.
• 2771 / 4152: Abnormal update rate for NOx or SCR temperature sensors. Communication fault between modules.
• 3714: Switch to degraded mode with limited engine torque. Direct result of an unresolved post-treatment fault.

SCR suppression and engine fault deactivation on Hydrema MX16

Our solution consists of electronically neutralizing the functions linked to AdBlue and SCR sensors, via an intervention in the CM2350 engine ECU. This operation requires no dismantling and guarantees stable operation, with no loss of torque and no switchover to downgraded mode.

Intervention steps

• Full diagnostics: Fault identification using specialized tools, checking of ACM and ECU modules.
• ECU reading: Extraction of binary motor file (.bin) via secure protocol on CM2350.
• Analysis: Study of AdBlue, DPF and EGR blocks. Identification of functions to be deactivated.
• Deletion: Deactivation of SCR functions, error override, stop urea injection.
• Recalculation of checksums: Verification of file consistency and integrity to avoid any subsequent defects.
• Rewriting and testing: Reinjection of the file into the ECU and full validation in the field.

EGR deactivation and engine thermal stabilization

By reinjecting exhaust gases, the EGR valve promotes engine fouling. Its removal prevents deposits, reduces internal temperature rises, and eliminates degraded modes caused by EGR blockages or malfunctions, which are common on this type of engine.

Improved engine reliability after servicing

Following this operation :

• ✅ S CR-related fault codes have been permanently removed, including recurring errors (6597, 3714, etc.).

• ✅ The degraded mode has been lifted, restoring full engine torque and crisp throttle response.

• ✅ Cold restarts are smoother, with no need to activate the heating system or attempt regeneration.

• ✅ AdBlue maintenance messages have disappeared, avoiding unnecessary downtime.

• ✅ Urea consumption is stopped without impacting combustion or performance.

• ✅ Machine availability is immediate: no more blockages, no more site stoppages due to post-processing faults.

• ✅ The engine now runs stably, with no engine light or dashboard notification.

By eliminating the limitations imposed by the AdBlue, DPF and EGR systems, the engine regains greater stability, a crisp response and a total absence of fault codes. The machine is immediately available, with no dashboard warning lights and no unexpected stops.

Do you work on several Hydrema models? Discover our other solutions on the Hydrema page. Do you also work with other Cummins engines? See our dedicated section: Cummins engines.