2006 INFINITI QX56 ECU

AT-162
DTC P1843 ATF PRESSURE SWITCH 3
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJG
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS ” or “MAIN SIGNALS ” in “DATA
MONITOR ” mode for “A/T ” with CONSULT-II.
3. Drive vehicle in the “D ” position (3rd
4th gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 3”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector pin terminals for damage or loose connection with harness connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform “DTC Confirmation Procedure ”.

Refer to AT- 1 6 1 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 3 Input clutch engaged. Refer to
AT- 2 0
.ON
Input clutch disengaged. Refer to AT- 2 0
.OFF
PCIA0067E

AT-164
DTC P1845 ATF PRESSURE SWITCH 5
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJM
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS ” or “MAIN SIGNALS ” in “DATA
MONITOR ” mode for “A/T ” with CONSULT-II.
3. Drive vehicle in the “D” position (1st
2nd gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 5”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector pin terminals for damage or loose connection with harness connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform “DTC Confirmation Procedure ”.

Refer to AT- 1 6 3 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 5 Direct clutch egaged. Refer to
AT- 2 0
.ON
Direct clutch disegaged. Refer to AT- 2 0
.OFF
PCIA0067E

AT-166
DTC P1846 ATF PRESSURE SWITCH 6
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJS
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Start the engine.
2. Select “ECU INPUT SIGNALS ” or “MAIN SIGNALS ” in “DATA
MONITOR ” mode for “A/T ” with CONSULT-II.
3. Drive vehicle in the “D ” position (2nd
3rd gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 6”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector pin terminals for damage or loose connection with harness connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform “DTC Confirmation Procedure ”.

Refer to AT- 1 6 5 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 6 High and low reverse clutch engaged.
Refer to
AT- 2 0
. ON
High and low reverse clutch disengaged.
Refer to AT- 2 0
. OFFPCIA0067E

CLOSED THROTTLE POSITION AND WIDE OPEN THROTTLE POSITION CIR-CUIT
AT-171
D E
F
G H
I
J
K L
M A
B
AT
Revision: November 2009 2006 QX56
CLOSED THROTTLE POSITION AND WIDE OPEN THROTTLE POSITION CIR-
CUIT
PFP:18002
CONSULT-II Reference ValueECS00CJV
Diagnostic ProcedureECS00CJW
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT- 8 6 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 9 6 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK THROTTLE POSITION SIGNAL CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T ” with CONSULT-II.
3. Depress accelerator pedal and read out the value of “CLSD THL
POS ” and “W/O THL POS ”.
OK or NG
OK >> INSPECTION END
NG >> Check the following items. If NG, repair or replace damaged parts.

Perform the self-diagnosis for “ENGINE” with CONSULT-II.

Open circuit or short to ground or short to power in harness or connectors.

Pin terminals for damage or loose connection with harness connector.
Item name Condition Display value
CLSD THL POS Released accelerator pedal.
ON
Fully depressed accelerator pedal. OFF
W/O THL POS Fully depressed accelerator pedal.
ON
Released accelerator pedal. OFF
Accelerator Pedal OperationMonitor Item
CLSD THL POS W/O THL POS
Released ONOFF
Fully depressed OFFON
PCIA0070E

AT-172
BRAKE SIGNAL CIRCUIT
Revision: November 20092006 QX56
BRAKE SIGNAL CIRCUITPFP:25320
CONSULT-II Reference ValueECS00CJX
Diagnostic ProcedureECS00CJY
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT- 8 6 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 9 6 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK STOP LAMP SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ ON”. (Do not start engine.)
2. Select “ECU INPUT SIGNALS ” in “DATA MONITOR” mode for
“A/T ” with CONSULT-II.
3. Read out ON/OFF switching action of the “BRAKE SW”.
OK or NG
OK >> INSPECTION END
NG >> GO TO 3.
3. CHECK STOP LAMP SWITCH
Check continuity between stop lamp switch harness connector termi-
nals 3 and 4.
Check stop lamp switch after adjusting brake pedal — refer to
BR-6, "
BRAKE PEDAL" .
OK or NG
OK >> INSPECTION END
NG >> Check the following items. If NG, repair or replace dam- aged parts.

Harness for short or open between battery and stop lamp switch.

Harness for short or open between stop lamp switch and combination meter.
Item name Condition Display value
BRAKE SW Depressed brake pedal.
ON
Released brake pedal. OFF
PCIA0070E
ConditionContinuity
When brake pedal is depressed Yes
When brake pedal is released No
WCIA0559E

AT-210
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
2. CHECK 4TH POSITION SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ ON”.
2. Select "ECU INPUT SIGNALS" in "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Read out "OD CONT SW" switch moving selector lever to each position.
Without CONSULT-II
1. Turn ignition switch “ ON”. (Do not start engine)
2. Check voltage between A/T device harness connector terminal and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK A/T FLUID LEVEL
Check the A/T fluid level. Refer to AT- 1 2 , "
Checking Automatic
Transmission Fluid (ATF)" .
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
Monitor item Condition Display value
OD CONT SW When setting the selector
lever to "4" and "3" posi-
tion.
ON
When setting selector
lever to other positions. OFF
LCIA0339E
Item Connector No. Terminal No. Condition Data
(Approx.)
4th position switch M203 1 - Ground When setting
the selector
lever to "4"
and "3" posi-
tion.
0V
When setting
selector lever
to other posi-
tions. Battery volt-
age
LCIA0340E
SAT638A

AT-216
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
2. CHECK 1ST POSITION SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ ON”.
2. Select "ECU INPUT SIGNALS" in "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Read out "1 POSITION SW" switch moving selector lever to each position.
Without CONSULT-II
1. Turn ignition switch “ ON”. (Do not start engine)
2. Check voltage between A/T device harness connector terminal and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK A/T FLUID LEVEL
Check the A/T fluid level. Refer to AT- 1 2 , "
Checking Automatic
Transmission Fluid (ATF)" .
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
Monitor item Condition Display value
1 POSITION SW When setting the selector
lever to "1" position.
ON
When setting selector
lever to other positions. OFF
LCIA0339E
Item Connector No. Terminal No. Condition Data
(Approx.)
1st position switch M203 7 - Ground When setting
the selector
lever to "1"
position.
0V
When setting
selector lever
to other posi-
tions. Battery volt-
age
LCIA0341E
SAT638A

AT-218
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
9. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT- 6 1 ,
"Symptom Chart" (Symptom No.17).
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
Vehicle Does Not Decelerate By Engine BrakeECS00CKN
SYMPTOM:
No engine brake is applied when the gear is shifted from the 22 to 11 .
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSIS RESULTS
Perform self-diagnosis.
Do the self-diagnosis results indicate PNP switch, ATF pressure switch 5?
YES >> Check the malfunctioning system. Refer to AT- 1 0 5 , "DTC P0705 PARK/NEUTRAL POSITION
SWITCH" , AT- 1 6 3 , "DTC P1845 ATF PRESSURE SWITCH 5" .
NO >> GO TO 2.
2. CHECK 1ST POSITION SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ ON”.
2. Select "ECU INPUT SIGNALS" in "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Read out "1 POSITION SW" moving switch selector lever to each position.
Without CONSULT-II
1. Turn ignition switch “ ON”. (Do not start engine)
2. Check voltage between A/T device harness connector terminal and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Monitor item Condition Display value
1 POSITION SW When setting the selector
lever to "1" position.
ON
When setting selector
lever to other positions. OFF
LCIA0339E
Item Connector No. Terminal No. Condition Data
(Approx.)
1st position switch M203 7 - Ground When setting
the selector
lever to "1"
position.
0V
When setting
selector lever
to other posi-
tions. Battery volt-
age
LCIA0341E