Mixture Heater Control System

Fig. 114 Mixture Heater Control System:

CIRCUIT OPERATION
The mixture control system is provided to heat the A/F mixture. This process helps atomize the mixture. Refer to EMISSION CONTROLS for further description of the fuel mixture heater.

Single Pole Normally Open Relay:

MIXTURE HEATER RELAY
When the ECU senses proper conditions for mixture heater operation, it provides the ground circuit to the relay, located in the relay box in the engine compartment. The relay closes and conducts the positive circuit to the heater.
The mixture heater control system operates under the following conditions:
1. Engine is running.
2. Water temperature is below 50° C (122° F) when starting the engine.
The system deactivates after several minutes have passed and the temperature is above 50° C (122° F).