DTC Advanced Diagnostics: P0191: General Description
The fuel rail pressure sensor senses fuel pressure and converts it into electrical signals. The powertrain control module (PCM) monitors the fuel pressure of which certain duration has passed from the vehicle OFF (LOCK) mode, and it is used for the malfunction determination. If the fuel pressure of which certain duration has passed from the vehicle OFF (LOCK) mode is not lowered from the fuel pressure of the previous vehicle OFF (LOCK) mode, or if the fuel pressure after the engine start does not increase from the fuel pressure of which certain duration passed from the vehicle OFF (LOCK) mode, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Once per driving cycle |
| Sequence | None |
| Duration | - |
| DTC Type | Two drive cycles, MIL on |