Cold Mixture Heater (Cmh) System - Toyota 4-Runner 1985 Repair Manual

EC-68
Charge
Light
Charge
Light
Relay
EMISSION CONTROL SYSTEMS (CARB.) - Auxiliary Systems
8. Cold Mixture Heater (CMH) System
A03086
Computer
CMH Relay
,..
I
I
EC4210
To reduce cold engine emission and improve drivability, the intake manifold riser is heated during cold engine operation
to accelerate vaporization of the liquid fuel.
IG S/W
Engine Coolant Temp.
OFF Not running
-
Not running
-
Below 43°C
ON
(109°F)
Running
Above 55°C
(131°F)
Voltmeter
Thermo S/W (1) Computer CMH Relay CMH
- -
OFF OFF
-
OFF
OFF OFF
ON ON
ON
ON
(Heated)
OFF OFF
OFF
OFF
INSPECTION OF CMH SYSTEM
1. START ENGINE
2. CHECK CMH WITH COLD ENGINE
(a) The coolant temperature should be below 43°C
(109°F).
(b) Using a voltmeter check that there is voltage between
the positive
(+)
terminal and intake manifold.
CAUTION: The voltmeter probe should be inserted from
the rear side of the connector.