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EC-350Revision: August 2007
DTC P0550 PSP SENSOR
2004 QX56
6. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00H6V
POWER STEERING PRESSURE SENSOR
1. Reconnect all harness connectors disconnected.
2. Start engine and let it idle.
3. Check voltage between ECM terminal 12 and ground under the
following conditions.
Removal and Installation UBS00H6W
POWER STEERING PRESSURE SENSOR
Refer to PS-31, "HYDRAULIC LINE" .
Condition Voltage
Steering wheel is being turned. 0.5 - 4.5V
Steering wheel is not being turned. 0.4 - 0.8V
MBIB0126E
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EC-424Revision: August 2007
DTC P1229 SENSOR POWER SUPPLY
2004 QX56
DTC P1229 SENSOR POWER SUPPLYPFP:16119
On Board Diagnosis LogicUBS00H9B
This self-diagnosis has the one trip detection logic.
FAIL -S AFE M OD E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureUBS00H9C
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 1 second.
4. If DTC is detected, go to EC-426, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1229
1229Sensor power supply circuit
shortECM detects a voltage of power source
for sensor is excessively low or high.
Harness or connectors
(APP sensor 1 circuit is shorted.)
(PSP sensor circuit is shorted.)
(Refrigerant pressure sensor circuit is
shorted.)
(EVAP control system pressure sensor circuit
is shorted.)
Accelerator pedal position sensor
Power steering pressure sensor
Refrigerant pressure sensor
EVAP control system pressure sensor
Engine operation condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
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EC-426Revision: August 2007
DTC P1229 SENSOR POWER SUPPLY
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.
Diagnostic ProcedureUBS00H9E
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-133, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
48 SBSensor power supply
(EVAP control system
pressure sensor)[Ignition switch: ON]Approximately 5V
49 R/YSensor power supply
(Refrigerant pressure
sensor)[Ignition switch: ON]Approximately 5V
68 W/LSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
90 LSensor power supply
(APP sensor 1)[Ignition switch: ON]Approximately 5V
BBIA0354E
Page 1618 of 3371

DTC P1229 SENSOR POWER SUPPLY
EC-427
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2. CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness
connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminal 7 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
3. CHECK SENSOR POWER SUPPLY CIRCUITS
Check the following.
Harness for short to power and short to ground, between the following terminals
OK or NG
OK >> GO TO 4.
NG >> Repair short to ground or short to power in harness or connectors.
4. CHECK COMPONENTS
Check the following.
EVAP control system pressure sensor (Refer to EC-307, "Component Inspection" .)
Power steering pressure sensor (Refer to EC-350, "Component Inspection" .)
Refrigerant pressure sensor (Refer to EC-607, "REFRIGERANT PRESSURE SENSOR" .)
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning components.
5. CHECK ACCELERATOR PEEDAL POSITION SENSOR
Refer to EC-582, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
BBIA0361E
Voltage: Approximately 5V
PBIB2070E
ECM terminal Sensor terminal Reference Wiring Diagram
48 EVAP control system pressure sensor terminal 3EC-304
49 Refrigerant pressure sensor terminal 1EC-608
68 Power steering pressure sensor terminal 1EC-347
90 APP sensor terminal 7EC-425
Page 1701 of 3371

EC-510Revision: August 2007
DTC P1564 ICC STEERING SWITCH
2004 QX56
DTC P1564 ICC STEERING SWITCHPFP:25551
Component DescriptionUBS00HYP
ICC 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 ACS-6, "
DESCRIPTION" for the ICC function.
CONSULT-II Reference Value in Data Monitor ModeUBS00HYQ
Specification data are reference values.
On Board Diagnosis LogicUBS00HYR
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this self-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" .
DTC Confirmation ProcedureUBS00HYS
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.
BBIA0469E
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
DIST SW
Ignition switch: ONDISTANCE switch: Pressed ON
DISTANCE switch: Released OFF
DTC No.Trouble Diagnosis
NameDTC Detecting Condition Possible Cause
P1564
1564ICC steering switch
An excessively high voltage signal from the
ICC steering switch is sent to ECM.
ECM detects that input signal from the ICC
steering switch is out of the specified range.
ECM detects that the ICC steering switch is
stuck ON.
Harness or connectors
(The switch circuit is open or shorted.)
ICC steering switch
ECM
Page 1702 of 3371
DTC P1564 ICC STEERING SWITCH
EC-511
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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 DISTANCE switch for at least 10 seconds, then release it
and wait at least 10 seconds.
8. Press CANCEL switch for at least 10 seconds, then release it
and wait at least 10 seconds.
9. If DTC is detected, go to EC-514, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
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Page 1703 of 3371
EC-512Revision: August 2007
DTC P1564 ICC STEERING SWITCH
2004 QX56
Wiring DiagramUBS00HYT
BBWA1330E
Page 1704 of 3371
DTC P1564 ICC STEERING SWITCH
EC-513
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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.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
67 BSensor ground
(ICC steering switch)[Engine is running]
Warm-up condition
Idle speedApproximately 0V
99 G/Y ICC steering switch[Ignition switch: ON]
ICC steering switch: OFFApproximately 4.3V
[Ignition switch: ON]
ON/OFF (MAIN) switch: PressedApproximately 0V
[Ignition switch: ON]
CANCEL switch: PressedApproximately 1.3V
[Ignition switch: ON]
DISTANCE switch: PressedApproximately 2.2V
[Ignition switch: ON]
COAST/SET switch: PressedApproximately 3V
[Ignition switch: ON]
ACCEL/RESUME switch: PressedApproximately 3.7V