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.
Evaporative leak detection strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. Powertrain Control Module (PCM) monitors vacuum level by means of fuel tank vacuum sensor input. At a predetermined time, EVAP purge solenoid and EVAP vent solenoid are turned on. This allows engine vacuum to draw a small vacuum on entire EVAP system. After desired vacuum level has been achieved, EVAP purge solenoid is turned off, sealing the system. If a small leak is detected, a DTC P0442 will set.
Conditions for setting this DTC are:
- DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134 and P1133 not set.
- BARO is greater than 75 kPa.
- ECT and IAT is 41-84°F (5-29°C) at engine start-up.
- IAT is not greater than 2°F (1°C) of ECT at engine start-up.
- ECT is not greater than 12°F (7°C) of IAT at engine start-up.
- Fuel tank level is 26-74 percent.
- TP angle is 9-35 percent.
- EVAP solenoid is at 50 percent PWM within 50 seconds of engine start-up.
- EVAP system is unable to detect vacuum during diagnostic test.