Code No. P0300 Ignition Coil (Power Transistor) System <Vehicles except for Hong kong>

OPERATION

The battery voltage is applied to the ignition coil (terminal No. 1) from the ignition switch and is earthed to the vehicle body from the ignition coil (terminal No. 2).

A power voltage of 12 V is applied to the ignition coil output terminal (terminal No. 3) from the engine-A/T-ECU (terminal No. 31, No. 32, No. 35 and No. 52.

FUNCTION

When the engine-A/T-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-A/T-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-A/T-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.

TROUBLE JUDGMENT

Check Condition

Engine speed is approximately 4,000 r/min or less.

Judgment Criterion

The determination signal for the open circuit is continuously output from the confirmation signal circuit for the ignition built in the engine-A/T-ECU.

PROBABLE CAUSES

Failed ignition coil

Open/short circuit in ignition primary circuit or loose connector contact

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-110, B-111, B-121 and B-120 ignition coil connectors

Q: Is the check result normal?

YES: Go to Step 2

.
NO: Repair or replace.

STEP 2. Check ignition coil itself.

Check ignition coil itself (Refer to GROUP 16 - Ignition System - On-vehicle Service - Ignition coil check ).

Q: Is the check result normal?

YES: Go to Step 3

.
NO: Replace ignition coil.

STEP 3. Perform resistance measurement at B-110, B-111, B-121 and B-120 ignition coil connectors.

Disconnect connector, and measure at harness side.

Resistance between terminal No. 2 and earth.

OK: 2 Ω or less

Q: Is the check result normal?

YES: Go to Step 4

.
NO:

Check and repair harness between ignition coil connector and body earth.

Check and repair harness between B-110 (terminal No. 2) No. 1 ignition coil connector and body earth.

Check and repair harness between B-111 (terminal No. 2) No. 2 ignition coil connector and body earth.

Check and repair harness between B-121 (terminal No. 2) No. 3 ignition coil connector and body earth.

Check and repair harness between B-120 (terminal No. 2) No. 4 ignition coil connector and body earth.

Check earthing line for open circuit and damage.

STEP 4. Check harness between ignition coil connector and engine-A/T-ECU connector.

Check and repair harness between B-110 (terminal No. 3) No. 1 ignition coil connector and C-135 (terminal No. 31) engine-A/T-ECU connector.

Check and repair harness between B-111 (terminal No. 3) No. 2 ignition coil connector and C-135 (terminal No. 32) engine-A/T-ECU connector.

Check and repair harness between B-121 (terminal No. 3) No. 3 ignition coil connector and C-135 (terminal No. 35) engine-A/T-ECU connector.

Check and repair harness between B-120 (terminal No. 3) No. 4 ignition coil connector and C-135 (terminal No. 52) engine-A/T-ECU connector.

Check output line for open/short circuit and damage.

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Repair.

STEP 5. MUT-II/III diagnosis code

Reconfirmation of diagnosis code.

Q: Is the diagnosis code set?

YES: Replace engine-A/T-ECU.
NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points


Code No. P0300 Ignition Coil (Power Transistor) System <Vehicles except for Hong kong>

OPERATION The battery voltage is applied to the ignition coil (terminal No. 1) from the ignition switch and is earthed to the vehicle body from the ignition coil (terminal No. 2). A power voltage of 12 V is applied to the ignition coil output terminal (terminal No. 3) from the engine-A/T-ECU (terminal No. 31, No. 32, No. 35 and No. 52.
FUNCTION When the engine-A/T-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-A/T-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-A/T-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.
TROUBLE JUDGMENT Check Condition Engine speed is approximately 4,000 r/min or less. Judgment Criterion The determination signal for the open circuit is continuously output from the confirmation signal circuit for the ignition built in the engine-A/T-ECU.
PROBABLE CAUSES Failed ignition coil Open/short circuit in ignition primary circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. Connector check: B-110, B-111, B-121 and B-120 ignition coil connectors
	Q: Is the check result normal? YES: Go to Step 2 . NO: Repair or replace.
	STEP 2. Check ignition coil itself. Check ignition coil itself (Refer to GROUP 16 - Ignition System - On-vehicle Service - Ignition coil check ). Q: Is the check result normal? YES: Go to Step 3 . NO: Replace ignition coil.
	STEP 3. Perform resistance measurement at B-110, B-111, B-121 and B-120 ignition coil connectors.
	Disconnect connector, and measure at harness side. Resistance between terminal No. 2 and earth. OK: 2 Ω or less Q: Is the check result normal? YES: Go to Step 4 . NO: Check and repair harness between ignition coil connector and body earth. Check and repair harness between B-110 (terminal No. 2) No. 1 ignition coil connector and body earth. Check and repair harness between B-111 (terminal No. 2) No. 2 ignition coil connector and body earth. Check and repair harness between B-121 (terminal No. 2) No. 3 ignition coil connector and body earth. Check and repair harness between B-120 (terminal No. 2) No. 4 ignition coil connector and body earth. Check earthing line for open circuit and damage.
	STEP 4. Check harness between ignition coil connector and engine-A/T-ECU connector.
	Check and repair harness between B-110 (terminal No. 3) No. 1 ignition coil connector and C-135 (terminal No. 31) engine-A/T-ECU connector. Check and repair harness between B-111 (terminal No. 3) No. 2 ignition coil connector and C-135 (terminal No. 32) engine-A/T-ECU connector. Check and repair harness between B-121 (terminal No. 3) No. 3 ignition coil connector and C-135 (terminal No. 35) engine-A/T-ECU connector. Check and repair harness between B-120 (terminal No. 3) No. 4 ignition coil connector and C-135 (terminal No. 52) engine-A/T-ECU connector. Check output line for open/short circuit and damage. Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
	STEP 5. MUT-II/III diagnosis code Reconfirmation of diagnosis code. Q: Is the diagnosis code set? YES: Replace engine-A/T-ECU. NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).