TROUBLE DIAGNOSISEC-91
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EC
Revision: November 2009 2006 QX56
Fail-safe ChartUBS00L04
When the DTC listed below is detected, the ECM enters fail-safe mode and the MIL lights up.
When there is an open circuit on MIL circuit, the ECM cannot warn the driver by lighting up MIL when
there is malfunction on engine control system.
Therefore, when electrical controlled throttle and part of ECM related diagnoses are continuously detected
as NG for 5 trips, ECM warns the driver that engine control system malfunctions and MIL circuit is open by
means of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MIL circuit are detected and demands
the driver to repair the malfunction.
DTC No. Detected itemsEngine operating condition in fail-safe mode
P0102
P0103 Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118 Engine coolant tempera-
ture sensor circuit Engine coolant temperature will be determined by ECM based on the time after turning
ignition switch ON or START.
CONSULT-II displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned
ON or START 40
°C (104 °F)
More than approx. 4 minutes after
ignition ON or START 80
°C (176 °F)
Except as shown above 40 - 80
°C (104 - 176 °F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling
fan operates while engine is running.
P0122
P0123
P0222
P0223
P2135 Throttle position sensor The ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor.
P0643 Sensor power supply ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2100
P2103 Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2101 Electric throttle control function ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2118 Throttle control motor ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2119 Electric throttle control actuator (When electric throttle control actuator does not function properly due to the return spring
malfunction:)
ECM controls the electric throttle actuator by regulating the throttle opening around the
idle position. The engine speed will not rise more than 2,000 rpm.
(When throttle valve opening angle in fail-safe mode is not in specified range:)
ECM controls the electric throttle control actuator by regulating the throttle opening to 20
degrees or less.
(When ECM detects the throttle valve is stuck open:)
While the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops,
the engine stalls.
The engine can restart in N or P position, and engine speed will not exceed 1,000 rpm or
more.
P2122
P2123
P2127
P2128
P2138 Accelerator pedal position
sensor
The ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor.
Engine operating condition in fail-safe mode
Engine speed will not rise more than 2,500 rpm due to the fuel cut
EC-92Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
Symptom Matrix ChartUBS00L05
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOMRefer-
ence page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel pump circuit 11232 22 3 2EC-604
Fuel pressure regulator system 334444444 4 EC-82
Injector circuit11232 22 2EC-598
Evaporative emission system 334444444 4 EC-32
Air Positive crankcase ventilation sys-
tem 334444444 41
EC-45
Incorrect idle speed adjustment 1 1 1 1 1EC-71
Electric throttle control actuator 112332222 2 2 EC-528
,
EC-534
,
EC-540
,
EC-545
IgnitionIncorrect ignition timing adjustment 33111 11 1EC-71
Ignition circuit 11222 22 2EC-618
Main power supply and ground circuit 22333 33 23 EC-145
Mass air flow sensor circuit
1
12 2
222 2 EC-171,
EC-180
Engine coolant temperature sensor circuit
333
EC-192,
EC-205
Air fuel ratio (A/F) sensor 1 circuit EC-213
,
EC-223
,
EC-232
,
EC-241
,
EC-575
Throttle position sensor circuit 22EC-198
,
EC-320
,
EC-483
,
EC-485
,
EC-560
Accelerator pedal position sensor circuit 3 2 1EC-453
,
EC-547
,
EC-553
,
EC-567
Knock sensor circuit 23EC-335
Crankshaft position sensor (POS) circuit 2 2 EC-340
Camshaft position sensor (PHASE) circuit 3 2EC-347
TROUBLE DIAGNOSISEC-93
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Revision: November 2009 2006 QX56
1 - 6: The numbers refer to the order of inspection.
(continued on next page)Vehicle speed signal circuit
2 3 33EC-442
Power steering pressure sensor circuit 23 3 EC-448
ECM 22333333333 EC-453,
EC-457
Park/Neutral position (PNP) switch circuit 3 3 3 33EC-465
Refrigerant pressure sensor circuit 233 4 EC-630
Electrical load signal circuit 3EC-596
Air conditioner circuit 223333333 3 2 AT C - 3 4
ABS actuator and electric unit (control unit)4EC-471
,
EC-472
or BRC-11
SYMPTOM
Refer-
ence page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
EC-94Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
SYSTEM — ENGINE MECHANICAL & OTHER
SYMPTOMReference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel tank 5
5 FL-10
Fuel piping
5 5 5 5 55FL-4
Vapor lock —
Valve deposit 5 555 55 5 —
Poor fuel (Heavy weight gaso-
line, Low octane) —
Air Air duct
55555 5 EM-15
Air cleaner
EM-15
Air leakage from air duct
(Mass air flow sensor — electric
throttle control actuator) 5555 EM-15
Electric throttle control actuator
EM-17
Air leakage from intake manifold/
Collector/GasketEM-17
Cranking Battery
111111
11
SC-4
Generator circuit
SC-17
Starter circuit3 SC-10
Signal plate6 EM-37
Park/Neutral position (PNP)
switch4
AT- 1 0 5
Engine Cylinder head
55555 55 5EM-63
Cylinder head gasket 4 3
Cylinder block
66666 66 64
EM-78
Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Va l v e
mecha-
nism Timing chain
55555 55 5 EM-37
Camshaft
EM-46
Intake valve
3EM-63
Exhaust valve
TROUBLE DIAGNOSISEC-105
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Revision: November 2009 2006 QX56
ECM Harness Connector Terminal LayoutUBS00L09
ECM Terminals and Reference ValueUBS00L0A
PREPARATION
1. ECM is located in the engine room passenger side behind bat-
tery.
2. Remove ECM harness connector.
3. When disconnecting ECM harness connector, loosen it with levers as far as they will go as shown in the figure.
4. Connect a break-out box (SST) and Y-cable adapter (SST) between the ECM and ECM harness connector.
Use extreme care not to touch 2 pins at one time.
Data is for comparison and may not be exact.
ECM INSPECTION TABLE
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground other than ECM terminals, such as the ground.
MBIB0045E
BBIA0386E
BBIA0387E
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
1 B ECM ground [Engine is running]
Idle speedBody ground
2 O/B A/F sensor 1 heater
(bank 1) [Engine is running]
Warm-up condition
Idle speed Approximately 5V
PBIB1584E
EC-106Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
3LThrottle control motor relay
power supply [Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
4 L/W Throttle control motor (Close) [Ignition switch: ON]
Engine: Stopped
Selector lever: D
Accelerator pedal: Fully released0 - 14V
5 L/B Throttle control motor (Open) [Ignition switch: ON]
Engine: Stopped
Selector lever: D
Accelerator pedal: Fully depressed0 - 14V
6GR Heated oxygen sensor 2
heater (bank 1) [Engine is running]
Engine speed: Below 3,600 rpm after the
following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load
0 - 1.0V
[Ignition switch: ON]
Engine: Stopped
[Engine is running]
Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
12 R Power steering pressure sen-
sor [Engine is running]
Steering wheel: Being turned
0.5 - 4.5V
[Engine is running]
Steering wheel: Not being turned 0.4 - 0.8V
13 O Crankshaft position sensor
(POS) [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle Approximately 10V
[Engine is running]
Engine speed: 2,000 rpm Approximately 10V
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
PBIB1104E
PBIB1105E
PBIB1041E
PBIB1042E
TROUBLE DIAGNOSISEC-107
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Revision: November 2009 2006 QX56
14 YCamshaft position sensor
(PHASE) [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle 1.0 - 4.0V
[Engine is running]
Engine speed: 2,000 rpm 1.0 - 4.0V
15 W Knock sensor (bank 1) [Engine is running]
Idle speedApproximately 2.5V
16 BR/R
A/F sensor 1 (bank 1) [Engine is running]
Warm-up condition
Idle speed Approximately 3.1V
35 BR/G Approximately 2.6V
56 LG/B Approximately 2.3V
75 P/B Approximately 2.3V
21
22
23
44 O/L
BR
GR/W
O Fuel injector No. 5
Fuel injector No. 3
Fuel injector No. 1
Fuel injector No. 7 [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
24 BR/W A/F sensor 1 heater
(bank 2) [Engine is running]
Warm-up condition
Idle speed Approximately 5V
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
PBIB1039E
PBIB1040E
SEC984C
SEC985C
PBIB1584E
EC-108Revision: November 2009
TROUBLE DIAGNOSIS
2006 QX56
25 O/GHeated oxygen sensor 2
heater (bank 2) [Engine is running]
Engine speed: Below 3,600 rpm after the
following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load
0 - 1.0V
[Ignition switch: ON]
Engine: Stopped
[Engine is running]
Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
32 L EVAP control system pres-
sure sensor [Ignition switch: ON]
Approximately 1.8 - 4.8V
34 R/B Intake air temperature sensor [Engine is running]Approximately 0 - 4.8V
Output voltage varies with intake
air temperature.
36 W Knock sensor (bank 2) [Engine is running]
Idle speedApproximately 2.5V
40
41
42
63 Y/G
P
L
G Fuel injector No. 6
Fuel injector No. 4
Fuel injector No. 2
Fuel injector No. 8 [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
45 L/Y EVAP canister purge volume
control solenoid valve [Engine is running]
Idle speed
Accelerator pedal: Not depressed even
slightly, after engine starting
BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Engine speed: About 2,000 rpm (More than
100 seconds after starting engine) BATTERY VOLTAGE
(11 - 14V)
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
SEC984C
SEC985C
SEC990C
SEC991C