Daimler Buses Tourismo, SETRA S531DT, Citaro recall: MDEG/HDEP Euro VI standard NOx sensor monitoring inoperative
- What's wrong
- The EU directive for commercial vehicles with the Euro 6 emissions standard stipulates that the NOx sensor signal is regularly checked for plausibility. The IUPR monitor (In Use Performance Ratio) was defined for this purpose. At a minimum 50% of vehicles in a class must…
- What to do
- Contact a Daimler Buses dealer to book the free repair. To remedy this an update software version in engine management (MCM) and exhaust gas aftertreatment (ACM) control units is required.
What’s wrong
The EU directive for commercial vehicles with the Euro 6 emissions standard stipulates that the NOx sensor signal is regularly checked for plausibility. The IUPR monitor (In Use Performance Ratio) was defined for this purpose. At a minimum 50% of vehicles in a class must have this monitor be active at least 10% of the possible time. This is not the case for the affected vehicles. Cause Parameter error in data record creation.
The fix
To remedy this an update software version in engine management (MCM) and exhaust gas aftertreatment (ACM) control units is required.
Vehicles affected
| Model | Built from | Built to | Vehicles |
|---|---|---|---|
| Tourismo | 1 Dec 2017 | 31 May 2019 | 191 |
| SETRA S531DT | 1 Jul 2018 | 30 Jun 2019 | 11 |
| Citaro | 1 Apr 2017 | 30 Sep 2018 | 9 |
| Tourismo | 1 Feb 2017 | 31 May 2019 | 621 |
How to check your vehicle
Use the official DVSA checker with your registration number to see if your exact vehicle is included. If it is, the manufacturer should have written to the registered keeper. The repair is free, even if you bought the vehicle second-hand.
Updated 31 March 2026. This page summarises an official notice. Details can change – always follow the official notice.