Early Fuel Evaporation ( EFE ): Testing and Inspection

Chart C-9:

PTC Heater:

PTC Heater Relay Circuit:

CIRCUIT DESCRIPTION:

Located between the throttle body and the intake manifold, the Positive Temperature Coefficient (PTC) heater is a heater grid which is controlled by the ECM through the PTC heater relay. When the engine coolant temperature is below 30°C (86°F), the heater is energized for up to ten seconds.

TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. This check can only be performed when the engine coolant is at approximately room temperature.

2. This check and the previous check determine if the ECM is sending the PTC control signal properly.