B2521

B2521 ECU CIRCUIT





Description
AFS control unit judges the vehicle condition from each signal. AFS control unit controls AFS function and the headlamp aiming.




DTC Logic

DTC DETECTION LOGIC
[B2521] ECU circuit






DTC CONFIRMATION PROCEDURE
1.DTC ERASE
Erase the DTC memory of AFS with CONSULT-III.
- GO TO 2.
2.DTC CONFIRMATION PROCEDURE
1. Turn the ignition ON.
2. Select the self-diagnosis with CONSULT-III.
Is DTC "B2521" detected?
YES - Refer to B2521.
NO - Refer to Intermittent Incident.




Diagnosis Procedure
1.CHECK EACH SENSOR POWER SUPPLY
1. Turn the ignition switch ON.
2. Check the voltage between the AFS control unit harness connector and the ground.





Is the measurement value within the standard value?
YES - GO TO 2.
Less than the standard value -GO TO 3.
Higher than the standard value-GO TO 4.
2.CHECK EACH SENSOR SIGNAL
Check the voltage between the AFS control unit harness connector and the ground.





Is the measurement value within the standard value?
YES - Replace AFS control unit.
Less than the standard value -GO TO 5.
Higher than the standard value-GO TO 6.
3.CHECK EACH SENSOR POWER SUPPLY SHORT CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect AFS control unit connector.
3. Check continuity between the AFS control unit harness connector and the ground.





Does continuity exist?
YES - Repair the harnesses or connectors.
NO - Replace AFS control unit.
4.CHECK EACH SENSOR POWER SUPPLY CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect AFS control unit connector.
3. Check the voltage between the AFS control unit harness connector and the ground.





Is the measurement value normal?
YES - Replace AFS control unit.
NO - Repair the harnesses or connectors.
5.CHECK EACH SENSOR SIGNAL SHORT CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect AFS control unit connector.
3. Check continuity between the AFS control unit harness connector and the ground.





Does continuity exist?
YES - Repair the harnesses or connectors.
NO - Replace AFS control unit.
6.CHECK EACH SENSOR SIGNAL SHORT CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect AFS control unit connector.
3. Turn the ignition switch ON.
4. Check the voltage between the AFS control unit harness connector and the ground.





Is the measurement value normal?
YES - Replace AFS control unit.
NO - Repair the harnesses or connectors.