Fuel Injected Engine

Fig. 23 System checker harness terminal identification:

Exc. 1987---88 Accord & Prelude
Before proceeding with test, ensure coolant temperature is above 5°F or below 104°F and atmospheric pressure is below 25.98 inches Hg.
1. Connect system checker harness between ECU and wire harness coupler.
2. Start engine, then measure voltage between terminal B4 (blue/black (+) and terminal A18 (black/red (-) of system checker harness, Fig. 23. Voltage should be 0.5---1.5 volts.
3. If voltage is greater than 9 volts, replace ECU. If no voltage is present, proceed as follows:
a. Check for open circuit in black/yellow wire between fuse and fast idle control solenoid valve.
b. Check for open circuit in blue/black wire on 1985 Accord models, red/green wire on 1986 Accord and 1986---87 Prelude models or green/yellow wire on Civic and CRX models between fast idle control solenoid valve and ECU.
c. Check for open circuit in fast idle control solenoid valve.