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ECM Power Source Circuit (Ignition Keyed)

CAUTION: If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction.
  1. Access ECM behind glove box. Leave electrical connectors attached to ECM. Turn ignition on. Backprobing connector, connect voltmeter negative lead to terminal No. 16 (Brown wire) at ECM E12 connector (this terminal is grounded). See Figure.
  2. Connect voltmeter positive lead to terminal No. 14 (Black/Yellow wire) at ECM E11 connector. If battery voltage is present, ECM keyed (ignition) power circuit is okay. If battery voltage is not present, go to next step.
  3. Check for an for an open circuit in wiring harness between ground and terminal No. 16 (Brown wire) at ECM E12 connector. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, go to next step.
  4. Measure voltage between chassis ground and terminal No. 9 (Black/Orange wire) at ECM E11 connector. If battery voltage is present, go to step 6). If battery voltage is not present, remove and inspect IGN fuse. If fuse is blown, check for short to ground in wiring. Repair as necessary.
  5. If IGN fuse is okay, disconnect ignition switch connector. With ignition switch in ON position, check for continuity between Black/White wire and Black/Red wire terminals at ignition switch. If continuity does not exist, replace ignition switch. If continuity exists, repair open circuit between battery and ignition switch, or between ignition switch and ECM.
  6. Turn ignition on. Measure voltage between chassis ground and terminal No. 24 (Black/Orange wire) at ECM E11 connector. If battery voltage is not present, replace ECM. If battery voltage is present, check EFI fuse. If EFI fuse is blown, repair circuit.
  7. If fuse is okay, check EFI main relay. See RELAYS  under MODULES, MOTORS, RELAYS & SOLENOIDS. If EFI main relay is okay, check circuit between chassis ground and terminal No. 24 at ECM E11 connector. If circuit is okay, repair circuit between battery and EFI fuse.
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