Overview of Troubleshooting

DTC P0451 can be set if any of the following conditions occur: Faulty fuel differential pressure sensor, related circuit, or ECM (M/T) or PCM (A/T).
To check a system blockage, do a performance test which uses a mechanical vacuum gauge and scan tool set on the fuel tank differential pressure sensor (TANK PRS SNSR73). The mechanical gauge reading is used to verify the reading from scan tool. A comparison of the mechanical gauge to scan tool determines the problem in the system.