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Home >> Isuzu >> 2008 >> Ascender LS, RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 4.2L - DTC P0366 To DTC P2444 >> DTC P2440 >> Circuit/System Testing
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Circuit/System Testing

IMPORTANT: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Disconnect the solenoid valve.
  2. Ignition ON, observe that a test lamp installed between the solenoid voltage supply circuit terminal 6 and the solenoid ground circuit terminal 4 is not illuminated.
    • If the test lamp is illuminated, test for a short to voltage on the solenoid voltage supply circuit. If the circuit tests normal, test or replace the relay.
  3. Inspect the AIR pump inlet and outlet hoses/pipes for restrictions.
  4. Inspect the solenoid valve for leaks.
  5. If the solenoid valve inspects OK, replace the AIR pump.