Circuit Description
WARNING: This page is about a different car, the 2000 Isuzu Hombre. However, it is still accessible from the selected car via links, so may be relevant.
EVAP system includes following components: fuel tank, EVAP vent solenoid, fuel tank pressure sensor, fuel pipes and hoses, vapor lines, fuel cap, EVAP emission canister, purge lines, and EVAP purge solenoid.
Evaporative leak detection strategy is based on applying vacuum to EVAP system and monitoring vacuum bleed. Vehicle Control Module (VCM) monitors vacuum level by means of fuel tank vacuum sensor input. VCM will set DTC P0446 if vacuum bleed rate is greater than predetermined value.
Conditions required to set DTC are:
- No ECT, HO2S, IAT, MAP, TP, or VSS sensor DTCs set.
- DTC P0125 not active.
- BARO is greater than 72.5 kPa.
- Excess vacuum exists in EVAP system.
- ECT and IAT sensor temperature is 41-84°F (5-29°C) at engine start-up.
- IAT is not greater than 2.7°F (1.5°C) of ECT at engine start-up.
- ECT is not greater than 15°F (8°C) of IAT at engine start-up.