Basic EEC Trouble Shooting

Perform a visual check of all computer related wiring and connectors. Ensure ignition and fuel system are in proper working order. Start and run engine at 1800 RPM until upper radiator hose is hot.
Connect analog voltmeter positive lead to Lt. Green/Black wire (circuit No. 99) at thermactor air diverter solenoid. Connect voltmeter negative lead to ground. Apply 20" Hg of vacuum to BP/MAP sensor "VENT" port for at least 30 seconds.
As vacuum is released, throttle kicker solenoid will extend to begin self-test. Voltmeter needle will also pulse 2 times (4 times on carbureted engines).
After a few minutes, throttle kicker will retract to indicate end of self-test mode. If any trouble codes are present, the ECA will then transmit code (s) to voltmeter. The 2 digit codes are obtained by counting voltmeter needle pulses.

With battery disconnected, check circuit (wire) continuity with an ohmmeter. If necessary, test resistance of all sensors and solenoids, using values given in COMPONENT RESISTANCE VALUES chart. Be sure to disconnect component from circuit before checking resistance.

CAUTION: The Exhaust Gas Oxygen (EGO) sensor resistance CANNOT be measured by connecting an ohmmeter directly to its output lead. Sensor damage will result if this is attempted.

EEC III DIAGNOSTIC CODES CHART

Code	Circuit
11	EEC III System Okay
12	RPM
15	Memory Check
21	ECT
22	MAP
23	TP
24	ACT
28	BP
31	EGR
32	EGR Closed
41	Fuel Lean
42	Fuel Rich
43	Engine Cold
44	Thermactor