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EC-514Revision: August 2007
DTC P1564 ICC STEERING SWITCH
2004 QX56
Diagnostic ProcedureUBS00HYU
1. CHECK ICC STEERING SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch ON.
2. Select “MAIN SW”, “RESUME/ACC SW”, “SET SW”, “DIST SW”
and “CANCEL SW” in “DATA MONITOR” mode with CONSULT-
II.
3. Check each item indication under the following conditions.
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 99 and ground with press-
ing each button.
OK or NG
OK >> GO TO 7.
NG >> GO TO 2.
Switch Monitor item Condition Indication
ON/OFF (MAIN)
switchMAIN SWPressed ON
Released OFF
COAST/SET switch SET SWPressed ON
Released OFF
ACCEL/RESUME
switchRESUME/ACC SWPressed ON
Released OFF
DISTANCE switch DIST SWPressed ON
Released OFF
CANCEL switch CANCEL SWPressed ON
Released OFF
MBIB0064E
Switch Condition Voltage [V]
ON/OFF (MAIN) switchPressed Approx. 0
Released Approx. 4.3
COAST/SET switchPressed Approx. 3.0
Released Approx. 4.3
ACCEL/RESUME switchPressed Approx. 3.7
Released Approx. 4.3
DISTANCE switchPressed Approx. 2.2
Released Approx. 4.3
CANCEL switchPressed Approx. 1.3
Released Approx. 4.3
PBIB0 311 E
Page 1706 of 3371

DTC P1564 ICC STEERING SWITCH
EC-515
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Revision: August 20072004 QX56
2. CHECK ICC STEERING SWITCH GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect combination switch harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between combination switch terminal
15 and ECM terminal 67.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. DETECT MALFUNCTIONING PART
Check the following.
Harness connectors M31, E152
Harness connectors E19, F33
Combination switch (spiral cable)
Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK ICC STEERING SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 99 and combination switch terminal 14.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.
Harness connectors M31, E152
Combination switch (spiral cable)
Harness for open and short between ECM and combination switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
6. CHECK ICC STEERING SWITCH
Refer to EC-516, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> Replace ICC steering switch.Continuity should exist.
BBIA0469E
Continuity should exist.
Page 1707 of 3371
EC-516Revision: August 2007
DTC P1564 ICC STEERING SWITCH
2004 QX56
7. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00HYV
ICC STEERING SWITCH
1. Disconnect combination switch (spiral cable).
2. Check continuity between combination switch (spiral cable) ter-
minals 14 and 15 with pushing each switch.
If NG, replace ICC steering switch.
Switch Condition Resistance [Ω]
ON/OFF (MAIN) switchPressed Approx. 0
Released Approx. 5,500
COAST/SET switchPressed Approx. 1,400
Released Approx. 5,500
ACCEL/RESUME switchPressed Approx. 2,600
Released Approx. 5,500
DISTANCE switchPressed Approx. 740
Released Approx. 5,500
CANCEL switchPressed Approx. 310
Released Approx. 5,500
PBIB1673E
Page 1708 of 3371

DTC P1564 ASCD STEERING SWITCH
EC-517
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DTC P1564 ASCD STEERING SWITCHPFP:25551
Component DescriptionUBS00HB8
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 EC-647, "
AUTOMATIC SPEED CONTROL DEVICE
(ASCD)" for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeUBS00HB9
Specification data are reference values.
On Board Diagnosis LogicUBS00HBA
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this diagnosis.
NOTE:
If DTC P1564 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer to
EC-351, "
DTC P0605 ECM" .
BBIA0362E
MONITOR ITEM CONDITION SPECIFICATION
MAIN SW
Ignition switch: ONON/OFF(MAIN) switch: Pressed ON
ON/OFF(MAIN) switch: Released OFF
CANCEL SW
Ignition switch: ONCANCEL switch: Pressed ON
CANCEL switch: Released OFF
RESUME/ACC SW
Ignition switch: ONACCEL/RESUME switch: Pressed ON
ACCEL/RESUME switch: Released OFF
SET SW
Ignition switch: ONCOAST/SET switch: Pressed ON
COAST/SET switch: Released OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1564
1564ASCD steering switch
An excessively high voltage signal from the
ASCD steering switch is sent to ECM.
ECM detects that input signal from the ASCD
steering switch is out of the specified range.
ECM detects that the ASCD steering switch is
stuck ON.
Harness or connectors
(The switch circuit is open or shorted.)
ASCD steering switch
ECM
Page 1709 of 3371
EC-518Revision: August 2007
DTC P1564 ASCD STEERING SWITCH
2004 QX56
DTC Confirmation ProcedureUBS00HBB
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 10 seconds.
4. Press ON/OFF(MAIN) switch for at least 10 seconds, then release it and wait at least 10 seconds.
5. Press ACCEL/RESUME switch for at least 10 seconds, then release it and wait at least 10 seconds.
6. Press COAST/SET switch for at least 10 seconds, then release it and wait at least 10 seconds.
7. Press CANCEL switch for at least 10 seconds, then release it and wait at least 10 seconds.
8. If DTC is detected, go to EC-521, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Page 1710 of 3371
DTC P1564 ASCD STEERING SWITCH
EC-519
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Revision: August 20072004 QX56
Wiring DiagramUBS00HBC
BBWA1368E
Page 1711 of 3371
EC-520Revision: August 2007
DTC P1564 ASCD STEERING SWITCH
2004 QX56
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
67 B Sensor ground[Engine is running]
Warm-up condition
Idle speed Approximately 0V
99 G/Y ASCD steering switch[Ignition switch: ON]
ASCD steering switch: OFF.Approximately 4V
[Ignition switch ON]
ON/OFF(MAIN) switch: PressedApproximately 0V
[Ignition switch: ON]
CANCEL switch: PressedApproximately 1V
[Ignition switch: ON]
COAST/SET switch: PressedApproximately 2V
[Ignition switch: ON]
ACCEL/RESUME switch: PressedApproximately 3V
Page 1712 of 3371

DTC P1564 ASCD STEERING SWITCH
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Revision: August 20072004 QX56
Diagnostic ProcedureUBS00HBD
1. CHECK ASCD STEERING SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch ON.
2. Select “MAIN SW”, “RESUME/ACC SW”, “SET SW” and “CANCEL SW” in “DATA MONITOR” mode with
CONSULT-II.
3. Check each item indication under the following conditions.
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 99 and ground with press-
ing each button.
OK or NG
OK >> GO TO 7.
NG >> GO TO 2.
2. CHECK ASCD STEERING SWITCH GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect combination switch harness connector.
4. Check harness continuity between combination switch terminal
15 and ECM terminal 67. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
Switch Monitor item Condition Indication
ON/OFF(MAIN)
switchMAIN SWPressed ON
Released OFF
ACCEL/RESUME
switchRESUME/ACC SWPressed ON
Released OFF
COAST/SET switch SET SWPressed ON
Released OFF
CANCEL switch CANCEL SW Pressed ON
Released OFF
SEC0 06 D
Switch Condition Voltage [V]
ON/OFF(MAIN) switchPressed Approx. 0
Released Approx. 4
ACCEL/RESUME switchPressed Approx. 3
Released Approx. 4
COAST/SET switchPressed Approx. 2
Released Approx. 4
CANCEL switchPressed Approx. 1
Released Approx. 4
PBIB0 311 E
Continuity should exist.
BBIA0362E