Code No. P0350: Ignition Coil Primary Circuit Malfunction <Vehicles with single oxygen sensor>

A power voltage of 12 V is applied to the each ignition coil from the engine-ECU (terminal CIL1, CIL2 and CIL3).

When the engine-ECU makes the power transistor in the unit be in OFF position, the battery voltage in the unit is applied to the power transistor unit, and that makes the power transistor unit be in ON position. The engine-ECU makes the power transistor in the unit be in ON, and that makes the power transistor unit be in OFF position.
In response to the signal from the engine-ECU, the power transistor unit is in ON position. The primary current is going to the ignition coil.When the power transistor unit is in OFF position, the primary current is interrupted and high voltage is generated in the secondary coil.

Check Condition

Judgement Criterion

FAIL-SAFE AND BACKUP FUNCTION

Failed ignition coil
Open/short circuit or harness damage in ignition primary circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

	Go to Step 2.

	Check Inspection Procedure - ignition circuit system (Refer to ).

Check ignition coil itself (Refer to GROUP 16 - Ignition System - Ignition Coil Check ).

	Go to Step 3.

	Replace the ignition coil.

OK: Continuity (2 Ω or less)

	Go to Step 4.

	Check and repair connector(s) or harness between earth line ignition coil connectors and body earth. Check earthing line for open circuit and damage.

Check and repair harness CIL1 line between No. 1 ignition coil connector and engine-ECU connector
Check and repair harness CIL2 line between No. 2 ignition coil connector and engine-ECU connector
Check and repair harness CIL3 line between No. 3 ignition coil connector and engine-ECU connector

	Go to Step 5.

	Repair the connector(s) or wiring harness.

	Replace the engine-ECU.

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