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

After the start.

Judgment Criterion

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

PROBABLE CAUSE

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

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-119 alternator connector

Q. Is the check result normal?

Go to Step 2 .

Repair or replace.

STEP 2. Perform voltage measurement at B-119 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: C-112 engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.

Q. Is the check result normal?

Go to Step 4 .

Repair or replace.

STEP 4. Check harness between B-119 (terminal No. 4) alternator connector and C-112 (terminal No. 86) engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.

note

Before checking harness, check intermediate connector B-17, and repair if necessary.

Check output line for open/short circuit.

Q. Is the check result normal?

Go to Step 5 .

Repair.

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

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

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

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

STEP 6. Perform voltage measurement at C-112 engine-ECU <M/T> connector or 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-119 (terminal No. 4) alternator connector and C-112 (terminal No. 86) engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.

note

Before checking harness, check intermediate connector B-17, and repair if necessary.

Check output line for damage.

Q. Is the check result normal?

Go to Step 8 .

Repair.

STEP 8. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace alternator.

	Intermittent malfunction (Refer to Group 00 - How to Use troubleshooting/Inspection Service Points ).