Prelude L4-1829cc 1800 ES,ET (1983)
c. Voltage should be available as flow, Fig. 72.
d. If there is no voltage, replace vacuum switch and repeat test.
3.
On all vehicles, check vacuum switch for proper operation.
4.
On 1983 vehicles, turn ignition switch on and check for voltage at blue wire at control unit connector. If there is no voltage, check blue wire
between ignition coil and control unit.
5.
On all vehicles, test or 15 mph speed sensor as outlined under "Speed Sensor, Test" procedure.
6.
On 1983 vehicles, test thermosensor as follows:
a. Ensure that engine is sufficiently cold by disconnecting hose No. 19 at charcoal canister. There must be no vacuum at idle.
b. Disconnect connector at control unit.
c. Check for resistance between blue/yellow and white/black terminals. Resistance should be above 1k ohm.
d. Run engine unit it reaches normal operating temperature, then check resistance as before. Resistance should be approximately 200 ohms.
e. If resistance is not within specifications, replace thermosensor and repeat test.
f.
If ohmmeter shows no continuity, check wiring.
g. If wiring is satisfactory, replace thermosensor and repeat test.
7.
On all vehicles, turn ignition switch on and check for voltage at black/yellow wire at control unit connector. If there is no voltage, check wiring.
8.
Check black or brown/black wire for continuity between control unit and suitable ground. There should be continuity.
9.
On all vehicles, check air intake temperature sensors for proper operation. Replace as required.
10.
If no faults were found in steps 1 through 9, replace control unit and repeat test.
