How To Use Circuit Test

DO NOT perform any CIRCUIT TEST unless told to do so by QUICK TEST . Make sure all non-EEC related faults are corrected. DO NOT replace any part unless directed to do so. When more than one service code is received, start with the first code displayed.
NOTE: Procedures in the TESTING section of this article are not in absolute numerical order. Procedures not related to this engine have been removed to eliminate confusion.
DO NOT measure voltage or resistance at ECA or connect any test lamps to it, unless specified. All measurements are made by probing the REAR of the connector. Isolate both ends of a circuit and turn key off whenever checking for shorts or continuity, unless specified.
Disconnect solenoids and switches from harness before measuring continuity, resistance, or applying 12-volts. Follow each test step in order until fault is found. After each repair, check all component connections and repeat CIRCUIT TEST(S).
An "open" is defined as any resistance reading higher than 5 ohms, unless specified in CIRCUIT TESTS . A "short" is defined as any resistance reading less than 10,000 ohms to ground, unless specified in CIRCUIT TESTS .
On TEST Q - FUEL CONTROL , to prevent replacement of good components, be aware that non-EEC related areas may also be at fault. These include ignition coil, distributor cap and rotor, spark plug wires, fouled spark plugs, CNAP problems, carburetor and electric choke problems (if used), EGR valve and gasket, air filter, poor power and ground circuits, fuel pressure, intake and exhaust manifold leaks, engine not at normal operating temperature, and problems with PCV valves or fuel contaminated engine oil.

NOTE: Fuel contaminated engine oil may affect some service codes. If this is suspected, remove PCV valve from valve cover and repeat QUICK TEST . If problem is corrected, change engine oil and filter.