Electronic Control Unit
- Test computer control system, using Digital Code Tester (49 G030 920 ), before testing electronic control unit. Connect voltmeter negative lead to ground. Turn ignition on and measure voltage at each ECU terminal. DO NOT probe directly on ECU side of connectors. Always insert probe on back side of connectors.
- Test ECU. See Fig 1 or Fig 2 for voltage specifications. If voltage at terminal(s) is(are) incorrect, check system components, wiring harnesses, and terminals of suspect components before replacing ECU.