Prelude L4-1955cc 2000 (1987)
Fast Idle Valve: Testing and Inspection
Fast Idle Control Solenoid Valve
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.
Fig. 23 System checker harness terminal identification
1987 Prelude
1.
Connect system checker harness between ECU and wire harness connector.
2.
Raise and support front of vehicle, block rear wheels and apply parking brake.
3.
Start engine, place shift or selector lever in second or 2 position and open throttle lever slightly, to at least 2000 RPM.
4.
Measure voltage between system checker harness terminals B4 (blue/black (+)) and A18 (black/red (-), Fig. 23. There should be 0---1.5 volts
available.
5.
If voltage is above 9 volts, replace ECU.
6.
If there is no voltage, proceed as follows:
a. Check for open circuit in black/yellow wire between regulator fuse (10 amp) and fast idle control solenoid valve.
b. Check for open circuit in red/green wire between fast idle control solenoid valve and ECU.
c. Check for open circuit in fast idle control solenoid valve.
