Code No. P0622: Alternator FR Terminal System

OPERATION

The energized state of the alternator field coil is inputted from the alternator (terminal No. 4) to the engine-A/T-ECU (terminal No. 86).

FUNCTION

A signal of the power supply duty ratio for the alternator field coil is inputted to the engine-A/T-ECU.
In response to the signal, the engine-A/T-ECU detects the alternator output current and controls the idling speed according to the output current (electric load).

TROUBLE JUDGMENT

Check Condition

The engine speed is more than approximately 500 r/min.

Judgment Criterion

Input voltage from the alternator FR terminal is approximately battery voltage for 20 seconds.

PROBABLE CAUSES

Failed alternator
Open circuit in alternator FR terminal circuit or loose connector
Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-116 alternator connector

Q. Is the check result normal?

	Go to Step 2 .

	Repair or replace the connector.

STEP 2. Perform voltage measurement at B-116 alternator connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 4 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 6 .

	Go to Step 3 .

STEP 3. Connector check: D-216 engine-A/T-ECU connector.

Q. Is the check result normal?

	Go to Step 4 .

	Repair or replace the connector.

STEP 4. Check harness between B-116 (terminal No. 4) alternator connector and D-216 (terminal No. 86) engine-A/T-ECU connector.

note

Before checking harness, check intermediate connector B-20, and repair if necessary.

Check output line for open circuit.

Q. Is the check result normal?

	Go to Step 5 .

	Repair the damaged harness wire.

STEP 5. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace the engine-A/T-ECU.

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

STEP 6. Connector check: D-216 engine-A/T-ECU connector

Q. Is the check result normal?

	Go to Step 7 .

	Repair or replace the connector.

STEP 7. Check harness between B-116 (terminal No. 4) alternator connector and D-216 (terminal No. 86) engine-A/T-ECU connector.

note

Before checking harness, check intermediate connector B-20, and repair if necessary.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 8 .

	Repair the damaged harness wire.

STEP 8. Perform voltage measurement at D-216 engine-A/T-ECU connector.

Measure engine-A/T-ECU terminal voltage.
Engine: Idle after warm-up
Transmission: P range
Cooling fan: Inactive
Voltage between terminal No. 86 and earth.

OK: Switching the headlamps to ON from OFF causes the voltage to fall.

Q. Is the check result normal?

	Go to Step 5 .

	Replace the alternator.