Code No. 64 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. 54).

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

After the start.

Judgment Criterion

Input voltage from alternator FR terminal continues to be battery voltage for 20 seconds.

PROBABLE CAUSE

Open circuit in alternator FR terminal circuit

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-19 intermediate connector

Q: Is the check result normal?

YES: Go to Step 2

.
NO: Repair.

STEP 2. Perform voltage measurement at B-19 intermediate connector.

Disconnect connector, and measure at male connector side.

Ignition switch: ON

Voltage between terminal No. 1 and earth.

OK: System Voltage

Q: Is the check result normal?

YES: Go to Step 6

.
NO: Go to Step 3

STEP 3. Connector check: C-111 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 4

.
NO: Repair.

STEP 4. Check harness between B-19 (terminal No. 1) intermediate connector and C-111 (terminal No. 54) engine-A/T-ECU connector.

Check output line for short circuit.

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Repair.

STEP 5. Check the trouble symptoms.

Q: Does trouble symptom persist?

YES: Replace engine-A/T-ECU.
NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

STEP 6. Perform voltage measurement at B-19 intermediate connector.

Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.

Ignition switch: ON

Voltage between terminal No. 1 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 9

.
NO: Go to Step 7

STEP 7. Connector check: B-30 alternator connector

Q: Is the check result normal?

YES: Go to Step 8

.
NO: Repair.

STEP 8. Check harness between B-30 (terminal No. 4) alternator connector and B-19 (terminal No. 1) intermediate connector.

Check output line for short circuit.

Q: Is the check result normal?

YES: Replace alternator.
NO: Repair.

STEP 9. Perform voltage measurement at B-19 intermediate connector.

Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.

Engine: Idling after warm up

Selector lever position: P

Radiator fan: Inactive

Voltage between terminal No. 1 and earth.

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

Q: Is the check result normal?

YES: Go to Step 5

.
NO: Go to Step 10

STEP 10. Connector check: B-30 alternator connector

Q: Is the check result normal?

YES: Go to Step 11

.
NO: Repair.

STEP 11. Check harness between B-30 (terminal No. 4) alternator connector and B-19 (terminal No. 1) intermediate connector.

Check output line for damage.

Q: Is the check result normal?

YES: Go to Step 12

.
NO: Repair.

STEP 12. Check harness between B-19 (terminal No. 1) intermediate connector and C-111 (terminal No. 54) engine-A/T-ECU connector.

Check output line for damage.

Q: Is the check result normal?

YES: Go to Step 13

.
NO: Repair.

STEP 13. Check the trouble symptoms.

Q: Does trouble symptom persist?

YES: Replace alternator.
NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points


Code No. 64 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. 54).
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 After the start. Judgment Criterion Input voltage from alternator FR terminal continues to be battery voltage for 20 seconds.
PROBABLE CAUSE Open circuit in alternator FR terminal circuit Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. Connector check: B-19 intermediate connector
	Q: Is the check result normal? YES: Go to Step 2 . NO: Repair.
	STEP 2. Perform voltage measurement at B-19 intermediate connector.
	Disconnect connector, and measure at male connector side. Ignition switch: ON Voltage between terminal No. 1 and earth. OK: System Voltage Q: Is the check result normal? YES: Go to Step 6 . NO: Go to Step 3 .
	STEP 3. Connector check: C-111 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 4 . NO: Repair.
	STEP 4. Check harness between B-19 (terminal No. 1) intermediate connector and C-111 (terminal No. 54) engine-A/T-ECU connector.
	Check output line for short circuit. Q: Is the check result normal? YES: Go to Step 5 . NO: Repair.
	STEP 5. Check the trouble symptoms. Q: Does trouble symptom persist? YES: Replace engine-A/T-ECU. NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).
	STEP 6. Perform voltage measurement at B-19 intermediate connector.
	Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness. Ignition switch: ON Voltage between terminal No. 1 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 9 . NO: Go to Step 7 .
	STEP 7. Connector check: B-30 alternator connector
	Q: Is the check result normal? YES: Go to Step 8 . NO: Repair.
	STEP 8. Check harness between B-30 (terminal No. 4) alternator connector and B-19 (terminal No. 1) intermediate connector.
	Check output line for short circuit. Q: Is the check result normal? YES: Replace alternator. NO: Repair.
	STEP 9. Perform voltage measurement at B-19 intermediate connector.
	Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness. Engine: Idling after warm up Selector lever position: P Radiator fan: Inactive Voltage between terminal No. 1 and earth. OK: Switching the headlamps to ON from OFF causes the voltage to fall. Q: Is the check result normal? YES: Go to Step 5 . NO: Go to Step 10 .
	STEP 10. Connector check: B-30 alternator connector
	Q: Is the check result normal? YES: Go to Step 11 . NO: Repair.
	STEP 11. Check harness between B-30 (terminal No. 4) alternator connector and B-19 (terminal No. 1) intermediate connector.
	Check output line for damage. Q: Is the check result normal? YES: Go to Step 12 . NO: Repair.
	STEP 12. Check harness between B-19 (terminal No. 1) intermediate connector and C-111 (terminal No. 54) engine-A/T-ECU connector.
	Check output line for damage. Q: Is the check result normal? YES: Go to Step 13 . NO: Repair.
	STEP 13. Check the trouble symptoms. Q: Does trouble symptom persist? YES: Replace alternator. NO: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).