A P0255 code on your 2019 GMC Acadia indicates an intermittent fault in the injection pump fuel metering control circuit. This diesel-specific code requires careful interpretation on the gasoline-powered Acadia.
Acadia Engine Information
The 2019 GMC Acadia offers the 2.5L four-cylinder or 3.6L V6—both gasoline engines. GM has not offered a diesel option in the Acadia. The gasoline direct injection systems in these engines work differently from diesel injection pumps and wouldn't generate this code under normal circumstances.
Intermittent Code Characteristics
Intermittent codes are notoriously difficult to diagnose because the fault occurs sporadically. However, if the code shouldn't exist at all (as with a diesel code on a gas vehicle), the 'intermittent' nature might reflect occasional diagnostic system glitches rather than an actual intermittent mechanical fault.
Investigation Steps
Use GM's GDS2 diagnostic system to verify the code. Check for any wiring damage near fuel system components that might create momentary signal anomalies. Look for loose connections in the fuel rail pressure sensor circuit—signal fluctuations here might be misinterpreted. Review any recent electrical work or aftermarket accessory installations.
Resolution Approach
Clear the code and drive through varied conditions. If it doesn't return, the issue may have been a one-time glitch. Persistent codes warrant dealer diagnosis to verify ECM health and software calibration. Address any actual fuel system symptoms separately from this code if they exist.