Code 51, 52 - Faulty ECM Ram/ROM

NOTE: See appropriate wiring diagram in WIRING DIAGRAMS article for terminal and connector identification.

NOTE: Test numbers refer to numbers on diagnostic chart.

Before replacing ECM, check circuit connections:
- Disconnect ECM harness connectors. Inspect all terminals and repair as necessary.
- Reconnect ECM harness connectors, and road test vehicle.
- Check for codes. If condition persists or code reappears, replace ECM.

Fig 1: Code 51, 52 - Diagnostic Flowchart Courtesy Isuzu Motor Co