MSP58 - DOSING CONTROL UNIT REPROGRAMMING. On the subject CX-5 vehicles, diagnosis for the Selective Catalytic Reduction (SCR) system failure may not function properly, leading to an inappropriate/delayed failure detection of the Dosing Control Unit (DCU), with codes DTC P2048 and DTC P229F. Mazda Motor Corporation has decided to conduct a Mazda Service Program (MSP) on certain 2019 CX-5 Diesel-fueled vehicles produced from March 23, 2018 through July 31, 2019. DTC P2048:00 - Urea injector circuit low input. Normally the diagnosis of urea injector coil resistance activates while the injector is operating and detects a failure based on the electric current value in the injector coil. On the subject vehicles, the diagnosis activates also while the injector is not operating due to inappropriate software of DCU, which allows the coil resistance to be temporarily judged to be normal, even if any abnormality occurs in the coil resistance value. DTC P229F:00 - NOx sensor No.2 system: NOx concentration malfunction. Normally the diagnosis of NOx sensor output characteristics (gain diagnosis) activates during IG-OFF and detects a failure based on the output value (gain value) of NOx sensor. On the subject vehicles, if a significant fluctuation occurs in the output value, the diagnosis may not be completed within the timing due to inappropriate software of DCU. This can cause delayed detection of sensor failure and lead to a delayed MIL illumination.
