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Fuel Pressure Regulator VSV Control Circuit

CAUTION: If ECM replacement is instructed, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair as necessary and repeat testing to confirm ECM malfunction.
  1. Check fuel pressure regulator VSV. See FUEL PRESSURE REGULATOR VACUUM SWITCHING VALVE (VSV) . Replace VSV as necessary. If VSV is okay, access ECM connectors behind glove box. Turn ignition on.
  2. Leave harness connectors attached to ECM. Backprobing connector, measure voltage between chassis ground and terminal No. 9 (Red/White wire) at ECM E12 connector. See Figure.
  3. If battery voltage is not present, repair circuit between EFI main relay and ECM. If battery voltage is present, check fuel pressure regulator by performing FUEL PRESSURE test under FUEL SYSTEM in BASIC TESTING article. If fuel pressure regulator is okay, replace ECM and retest.
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