Code No. P064C: Glow Control Unit Malfunction

The electrical current source is supplied from the engine control relay connector terminal to the glow control unit connector terminal. Also, it is supplied from the glow control unit connector terminal to the body earth.
The request signal of operating the glow plug is input into the glow control unit connector terminal from the engine-ECU connector terminal G/CT.
The voltage for the glow plug is applied from the battery to the glow control unit connector terminal.
The voltage is applied from the glow control unit connector terminal to each glow plug.
The diagnosis signal is output from the glow control unit connector terminal to the engine-ECU connector terminal G/DA.

The voltage applied to the glow control unit from the battery is applied to each glow plug in the duty ratio according to the signal from the engine ECU.

Check Conditions

Judgement Criterion

Failed glow control unit
Open/short circuit or harness damage in glow plug power supply circuit or loose connector contact.
Failed engine-ECU

DIAGNOSIS PROCEDURE

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Check the voltage between the glow control unit connector (power supply line) and body earth.
OK: System voltage

	Go to Step 2.

	Repair power supply line between glow control unit connector and battery.

	Go to Step 3.

	Repair the connector(s) or wiring harness.

	Go to Step 4.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).

After replacing the glow control unit, reconfirm whether the diagnosis code is set.

	Replace the engine-ECU.

	Check is end.