P2421 Possible Causes
- Faulty Evaporative Emission Vent Shut Valve
- Evaporative Emission Vent Shut Valve Circuit Open or Shorted
- Poor Electrical Connection in Evaporative Emission Vent Shut Valve Circuit
How to Fix Code P2421
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
P2421 Symptoms
Possible
Illuminated Engine Light (or Service Engine Soon Warning Light)
P2421 Meaning
The Fuel Tank Pressure (FTP) sensor output indicates atmospheric pressure of 0 kPa (0 in.Hg, 0 mmHg) before purge starts because the Evaporative Emission (EVAP) Canister Vent Shut Valve is normally open (open to atmosphere). The sensor indicates a negative pressure (vacuum) value during purge.
When the FTP sensor indicates vacuum after engine start, there is possibility of FTP sensor zero point offset failure or EVAP canister vent shut valve failure in closed position. Therefore, 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 internal fuel tank pressure is below the specified value (excessive vacuum is detected) at engine start, malfunction detection must be performed as follows because it is difficult to distinguish between FTP sensor range problem (P1454) and EVAP canister purge shut valve stuck closed (P2422).
1. If no Diagnostic Trouble Code (DTC) (P1454 or P2422) is stored, both DTCs are stored.
2. If both temporary DTCs (P1454 and P2422) are stored and excessive vacuum is detected, both DTCs are stored.
3. If one temporary DTC (P1454 or P2422) is stored and excessive vacuum is detected, the PCM stores the DTC of the temporary DTC that was stored.