# P1121 on the 2018 Mack Terrapro

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

This code is specific to a manufacturer and is not described here.

## Bulletins for this model year that name P1121

- [10162587](https://open.wenmarpro.com/bulletins/10162587), 2019-07-15: Exhaust Gas Recirculation \(EGR\) System \- Fault Codes SPN 412 FMI 0,2,5; Diagnostic Trouble Codes \(DTC\) P040A, P040B, P1121 \- Temperature Sensor Inspection
- [10160169](https://open.wenmarpro.com/bulletins/10160169), 2019-05-20: Diagnostic / Troubleshooting Procedures For EGR System Components; Diagnostic Trouble Codes \(DTC\) P0401\-00, P0402\-00, P04DD\-00, P1121\-00, P1121\-98 Or SPN 2659 FMI 16, SPN 2659 FMI 18, SPN 412 FMI 0, SPN 412 FMI 15 \- US10, US10\+OBD13, US14\+OBD\*, US17\+OBD\* With A Variable Geometry Turbocharger \(VGT\)