Page 1817 of 3371

EC-626Revision: August 2007
ASCD BRAKE SWITCH
2004 QX56
7. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check voltage between stop lamp switch terminal 3 and ground
with CONSULT -II or tester.
OK or NG
OK >> GO TO 9.
NG >> GO TO 8.
8. DETECT MALFUNCTIONING PART
Check the following.
Harness connectors M31, E152
Fuse block (J/B) connector M60
10A fuse
Harness for open or short between stop lamp switch and fuse
>> Repair open circuit or short to ground or short to power in harness or connectors.
9. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 4.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 10.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
10. CHECK STOP LAMP SWITCH
Refer to EC-627, "
Component Inspection"
OK or NG
OK >> GO TO 11.
NG >> Replace stop lamp switch.
BBIA0373E
Voltage: Battery voltage
PBIB2309E
Continuity should exist.
Page 1818 of 3371

ASCD BRAKE SWITCH
EC-627
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Revision: August 20072004 QX56
11 . CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00HDS
ASCD BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.
3. Check harness continuity between ASCD brake switch terminals
1 and 2 under the following conditions.
If NG, adjust ASCD brake switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
STOP LAMP SWITCH
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check harness continuity between stop lamp switch terminals 3
and 4 under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
Condition Continuity
When brake pedal is fully released. Should exist.
When brake pedal is depressed. Should not exist.
PBIB1536E
Condition Continuity
When brake pedal is fully released. Should not exist.
When brake pedal is depressed. Should exist.
PBIB2310E
Page 1819 of 3371

EC-628Revision: August 2007
ASCD INDICATOR
2004 QX56
ASCD INDICATORPFP:24814
Component DescriptionUBS00HDT
ASCD indicator lamp illuminates to indicate ASCD operation status. Lamp has two indicators, CRUISE and
SET, and is integrated in combination meter.
CRUISE indicator illuminates when ON/OFF switch on ASCD steering switch is turned ON to indicated that
ASCD system is ready for operation.
SET indicator illuminates when following conditions are met.
CRUISE indicator is illuminated.
SET switch on ASCD steering switch is turned ON while vehicle speed is within the range of ASCD set-
ting.
SET indicator remains lit during ASCD control.
Refer to EC-647, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)" for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeUBS00HDU
Specification data are reference value.
MONITOR ITEM CONDITION SPECIFICATION
CRUISE LAMP
Ignition switch: ONON/OFF(MAIN) switch: Pressed
at the 1st time → at the 2nd timeON → OFF
SET LAMP
ON/OFF switch: ON
When vehicle speed is
between 40 km/h (25 MPH)
and 144 km/h (89 MPH)
COAST/SET switch: Pressed ON
COAST/SET switch: Released OFF
Page 1820 of 3371
ASCD INDICATOR
EC-629
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Revision: August 20072004 QX56
Wiring DiagramUBS00HDV
BBWA1996E
Page 1821 of 3371
EC-630Revision: August 2007
ASCD INDICATOR
2004 QX56
Diagnostic ProcedureUBS00HDW
1. CHECK OVERALL FUNCTION
Check ASCD indicator under the following conditions.
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
2. CHECK DTC
Check that DTC U1000 or U1001 is not displayed.
OK or NG
OK >> GO TO 3.
NG >> Perform trouble diagnosis for DTC U1000, U1001. Refer to EC-135, "
DTC U1000, U1001 CAN
COMMUNICATION LINE" .
3. CHECK DTC WITH COMBINATION METER
Refer to DI-5, "
COMBINATION METERS" .
OK or NG
OK >> GO TO 4.
NG >> Go to DI-5, "
COMBINATION METERS" .
4. CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
ASCD INDICATOR CONDITION SPECIFICATION
CRUISE LAMP
Ignition switch: ONON/OFF(MAIN) switch: Pressed at
the 1st time → at the 2nd timeON → OFF
SET LAMP
ON/OFF(MAIN) switch: ON
When vehicle speed is between
40 km/h (25 MPH) and 144 km/h
(89 MPH)
COAST/SET switch: Pressed ON
COAST/SET switch: Released OFF
Page 1822 of 3371
MIL AND DATA LINK CONNECTOR
EC-631
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Revision: August 20072004 QX56
MIL AND DATA LINK CONNECTORPFP:24814
Wiring DiagramUBS00HDX
BBWA1997E
Page 1823 of 3371
EC-632Revision: August 2007
MIL AND DATA LINK CONNECTOR
2004 QX56
BBWA11 97 E
Page 1824 of 3371

EVAPORATIVE EMISSION SYSTEM
EC-633
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Revision: August 20072004 QX56
EVAPORATIVE EMISSION SYSTEMPFP:14950
DescriptionUBS00HDY
SYSTEM DESCRIPTION
The evaporative emission system is used to reduce hydrocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplished by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into the EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not operating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume control solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve also shuts off the vapor purge line during decelerating and
idling.
PBIB1631E