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-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 86).

FUNCTION

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

TROUBLE JUDGMENT

Check Condition

Engine speed is 500 r/min or higher.

Judgment Criterion

Input voltage from the alternator FR terminal has continued to be approximately battery positive voltage for 20 seconds.

PROBABLE CAUSES

Failed alternator
Open/short circuit in alternator FR terminal circuit or loose connector contact
Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

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 male connector 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-245 engine-ECU <M/T> connector or D-216 engine-A/T-ECU <A/T> 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-245 (terminal no. 86) engine-ECU <M/T> connector or D-216 (terminal No. 86) engine-A/T-ECU <A/T> connector.

note

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

Check output line for open/short circuit.

Q. Is the check result normal?

	Go to Step 5 .

	Repair the damaged harness wire.

STEP 5. Check the trouble symptoms.

Q. Does trouble symptom persist?

	Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.

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

STEP 6. Perform voltage measurement at D-245 engine-ECU <M/T> connector or D-216 engine-A/T-ECU <A/T> connector.

Measure engine-ECU <M/T> or engine-A/T-ECU <A/T> terminal voltage.
Engine: Idle after warm-up
Transmission: Neutral <M/T> or P range <A/T>
Radiator 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 7 .

	Go to Step 5 .

STEP 7. Check harness between B-116 (terminal No. 4) alternator connector and D-245 (terminal no. 86) engine-ECU <M/T> connector or D-216 (terminal No. 86) engine-A/T-ECU <A/T> 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. Check trouble symptom.

Q. Same symptoms regenerated?

	Replace the alternator.

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