P1564 ASCD STEERING SWITCH

Description
ASCD steering switch has variant values of electrical resistance for each button. ECM reads voltage variation of switch, and determines which button is operated. Refer to See: Cruise Control\Description and Operation\System Diagram for the ASCD function.

DTC Logic

DTC DETECTION LOGIC

NOTE:
If DTC P1564 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer to See: P0605.

1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds. >> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDURE

1. Turn ignition switch ON and wait at least 10 seconds.
2. Press MAIN switch for at least 10 seconds, then release it and wait at least 10 seconds.
3. Press CANCEL switch for at least 10 seconds, then release it and wait at least 10 seconds.
4. Press RESUME/ACCELERATE switch for at least 10 seconds, then release it and wait at least 10 seconds.
5. Press SET/COAST switch for at least 10 seconds, then release it and wait at least 10 seconds.
6. Check DTC. Is DTC detected?

YES >> Go to Diagnosis Procedure.
NO >> Inspection END

Diagnosis Procedure
1.CHECK GROUND CONNECTION

1. Turn ignition switch OFF.
2. Check ground connection E9. Refer to Ground Inspection in See: Testing and Inspection\Initial Inspection and Diagnostic Overview\Service Information For Electrical Incident\Circuit Inspection. Is the Inspection result normal?

YES >> GO TO 2.
NO >> Repair or replace ground connection.
2.CHECK ASCD STEERING SWITCH CIRCUIT
With CONSULT-III

1. Turn ignition switch ON.
2. Select "MAIN SW", "CANCEL SW", "RESUME/ACC SW" and "SET SW" in "DATA MONITOR" mode with CONSULT-III.
3. Check each item indication under the following conditions.

1. Turn ignition switch ON.

2. Check the voltage between ECM harness connector terminals under the following conditions.

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect combination switch harness connector.
4. Check the continuity between combination switch and ECM harness connector.

5. Also check harness for short to ground and short to power. Is the Inspection result normal?

YES >> GO TO 5.
NO >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.

• Harness connectors E30, M1
• Combination switch (spiral cable)
• Harness for open and short between ECM and combination switch >> Repair open circuit, short to ground or short to power in harness or connectors.

5.CHECK ASCD STEERING SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check the continuity between combination switch and ECM harness connector.

2. Also check harness for short to ground and short to power. Is the Inspection result normal?

YES >> GO TO 7.
NO >> GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.

• Harness connectors E30, M1
• Combination switch (spiral cable)
• Harness for open and short between ECM and combination switch >> Repair open circuit, short to ground or short to power in harness or connectors.

7.CHECK ASCD STEERING SWITCH
Refer to Component Inspection.
Is the Inspection result normal?
YES >> GO TO 8.
NO >> Replace ASCD steering switch.
8.CHECK INTERMITTENT INCIDENT
Refer to See: Testing and Inspection\Initial Inspection and Diagnostic Overview\Service Information For Electrical Incident\Intermittent Incident.
>> Inspection END

Component Inspection
1.CHECK ASCD STEERING SWITCH

1. Turn ignition switch OFF.
2. Disconnect combination switch (spiral cable) harness connector.

3. Check resistance between combination switch harness connector terminals as per the following.