Code No. P0622: Alternator FR Terminal System








OPERATION



  • The energised 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.