The 2023 Chevrolet Traverse's P0191 code indicates the Fuel Rail Pressure sensor's output is outside expected range for current operating conditions. Unlike circuit codes, P0191 means the sensor is communicating but values don't match what the ECU expects based on engine load, RPM, and fuel demand.
Understanding P0191
P0191 indicates a correlation error—the FRP reading doesn't match calculated values. For example, if the engine is under load requiring high fuel pressure but the sensor shows low pressure (or vice versa), this mismatch triggers P0191. The sensor works but values are unexpected.
Traverse Fuel System
The 2023 Traverse uses a 3.6L V6 with direct fuel injection. The high-pressure fuel pump creates rail pressure typically ranging from 500-2,500+ PSI depending on operating conditions. The ECU constantly adjusts pressure based on demand and monitors the FRP sensor to verify results.
Common Causes of P0191
Actual fuel pressure problems can trigger P0191 if pressure is genuinely outside expected range. A weak high-pressure fuel pump, leaking injector, or pressure regulator fault causes actual pressure issues the sensor accurately reports.
A failing FRP sensor that's drifted from calibration provides readings that don't reflect actual pressure. The sensor may function but report inaccurate values.
Fuel quality or contamination can affect system pressure. Water in fuel, incorrect octane, or degraded fuel affects combustion and pressure regulation.
Diagnostic Approach
Compare FRP sensor readings to known specifications at idle and under load. If possible, verify actual fuel pressure with a mechanical gauge against sensor readings. Check for TSBs specific to the Traverse fuel system. Inspect for fuel leaks at the rail or injectors.