Conditions for Setting the DTC
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
P1111
- The engine is changing from Gasoline mode to CNG mode.
- A fault is detected on the IAT signal or control circuits.
- The above conditions are present for greater than 1 s.
- This DTC runs continuously when the above conditions are met.
P1127
- The engine is running in CNG mode.
- A fault is detected on the IAT signal or control circuits.
- The intake air temperature (IAT) is more than 40°C (104°F).
- The above conditions are present for greater than 5 s.
- This DTC runs continuously when the above conditions are met.