How To Use Circuit Tests

1)  Ensure all non-EEC-IV related faults found while performing steps in BASIC TESTING article in this section have been corrected. Follow each test step in order until fault is found. When more than one code is retrieved, start with first code displayed.

2)  CIRCUIT TESTS ensure electrical circuits are okay before sensors or other components are replaced. Always test circuits for continuity between sensor and PCM. Test all circuits for short to power, opens or short to ground. Voltage Reference (VREF) and Voltage Power (VPWR) circuits should be tested with ignition on unless otherwise specified in CIRCUIT TESTS.

3) DO NOT  measure voltage or resistance at PCM. DO NOT  connect any test light unless specified in testing procedure. All measurements are made by probing rear of connector. Isolate both ends of a circuit and turn ignition off when checking continuity.

4)  Disconnect solenoids and switches from harness before measuring continuity and resistance or applying voltage. After each repair, reconnect all component connections and repeat QUICK TEST.

5)  An open circuit is defined as a resistance reading of greater than 5 ohms. This specification tolerance may be too high for some items in EEC-IV system. If resistance approaches 5 ohms, always clean suspect connector and coat it with protective dielectric silicone grease. A short is defined as a resistance reading of less than 10,000 ohms to ground, unless stated otherwise in CIRCUIT TEST.

CIRCUIT TESTS are grouped as follows.

• A-C - No Start & Voltage Tests
• DA-DS - Input Sensor Tests
• FD-FF - Additional Input Component Tests
• G-J - Fuel Control System Tests
• KA-TG - PCM Output Tests