Inspection Procedure 21: Alternator System

OPERATION

The excitation current is supplied from the engine-ECU (terminal No. 152 and terminal No. 153) to the alternator (terminal No. 1).
The alternator load signal is inputted from the alternator (terminal No. 2) to the engine-ECU (terminal No. 102).

FUNCTION

Controls the initiating excitation current to the alternator in accordance with the signals provided by the engine-ECU.

PROBABLE CAUSES

Failed alternator
Open or shorted alternator circuit, harness damage, or connector damage
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-14 alternator connector

Q. Is the check result normal?

	Go to Step 2 .

	Repair or replace the connector.

STEP 2. Connector check: B-06 engine-ECU connector

Q. Is the check result normal?

	Go to Step 3 .

	Repair or replace the connector.

STEP 3. Check harness between B-14 (terminal No. 2) alternator connector and B-06 (terminal No. 102) engine-ECU connector.

note

Before checking harness, check intermediate connector B-07, and repair if necessary

Check output line for open/short circuit and damage.

Q. Is the check result normal?

	Go to Step 4 .

	Repair the damaged harness wire.

STEP 4. Check harness between B-14 (terminal No. 1) alternator connector and B-06 (terminal No. 152 and terminal No. 153) engine-ECU connector.

note

Before checking harness, check intermediate connector B-07, and repair if necessary

Check power supply line for open/short circuit and damage.

Q. Is the check result normal?

	Go to Step 5 .

	Repair the damaged harness wire.

STEP 5. Replace the alternator.

After replacing the alternator, re-check the trouble symptoms.

Q. Does trouble symptom persist?

	Go to Step 6 .

	The check is end.

STEP 6. Check the trouble symptoms.

Q. Does trouble symptom persist?

	Replace the engine-ECU.

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