Test I: Insufficient Heat During Engine Idle

PINPOINT TEST I: INSUFFICIENT HEAT DURING ENGINE IDLE

I1-I5:

I5-I7:

I8-I11:

I11-I12:

Normal Operation
Under normal operation, the auxiliary coolant pump relay coil receives a ground from the Dual Automatic Temperature Control (DATC) module through circuit 91S-FA76 (BN/BL). The Coil receives battery voltage through circuit 30-FA74 (RD/GN). Battery voltage is supplied to the relay contacts from circuit 30-FA74 (RD/GN). When the relay coil is energized, voltage is delivered to the auxiliary coolant pump motor through circuit 30S-FB1 (RD/YE). Ground for the motor is provided through circuit 31-FB1 (BK/YE).

Possible Causes
- An open in circuit 31-FB1 (BK/YE), 30-FA74 (RD/GN), 30S-FB1 (RD/YE) or 91S-FA76 (BN/BL).
- A short to voltage in circuit 91S-FA76 (BN/BL).
- Auxiliary coolant pump relay.
- Auxiliary coolant pump motor.
- DATC module.