Test 12 - Vacuum Switching Valve (Code 25 And 53)
- Disconnect MCU terminal connectors at MCU, and at vacuum switching valve. Check circuit between pin 35 and LT. Green/Yellow wire for continuity and grounds. Repair or replace defective wires or connections.
- Check vacuum switching valve. Refer to the appropriate FUEL INJECTION SYSTEM - ISUZU I-TEC article in the FUEL SYSTEMS section.