DTC Advanced Diagnostics: P2422: General Description

Courtesy of HONDA, U.S.A., INC.

Courtesy of HONDA, U.S.A., INC.

The fuel tank pressure (FTP) sensor output is near atmospheric pressure (0 kPa (0 mmHg, 0 inHg)) before purge starts since the evaporative emission (EVAP) canister vent shut valve is normally open (to the atmosphere). The sensor indicates a negative pressure value (vacuum) while purging. When the FTP sensor indicates vacuum after the engine starts, an FTP sensor zero point shift failure or an EVAP canister vent shut valve stuck closed can occur. To prevent these failures, the powertrain control module (PCM) monitors the FTP sensor output after purge starts. The PCM detects a malfunction of the EVAP canister vent shut valve if the output indicates excessive vacuum. However, if the fuel tank internal pressure is below the specified value (excessive vacuum is detected) when starting the engine, the malfunction detection should be done as follows because it is difficult to distinguish between FTP sensor range problem (P1454) and an EVAP canister vent shut valve stuck closed problem (P2422).

• If neither Pending DTCs (P1454 nor P2422) are stored, both Pending DTCs are stored when excessive vacuum is detected at engine start.
• If both Pending DTCs (P1454 and P2422) are stored and excessive vacuum is detected, both Confirmed DTCs are stored.
• If either Pending DTC (P1454 or P2422) is stored and excessive vacuum is detected, the PCM stores the Confirmed DTC which the Pending DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type 

*: Elapsed time after the FTP sensor output exceeds the malfunction threshold.

**: Excessive negative pressure is detected.