2006 INFINITI QX56 brake sensor

AT-42
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
TROUBLE DIAGNOSISPFP:00004
DTC Inspection Priority ChartECS00CE9
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC U1000 is displayed with other DTCs, first perform the trouble diagnosis for DTC U1000. Refer to
AT- 9 6
.
Fail-SafeECS00CEA
The TCM has an electrical fail-safe mode. This mode makes it possible to operate even if there is an error in a
main electronic control input/output signal circuit. In fail-safe mode the transmission is fixed in 2nd, 4th or 5th
(depending on the breakdown position), so the customer should feel “slipping” or “poor acceleration ”.
Even when the electronic circuits are normal, under special conditions (for example, when slamming on the
brake with the wheels spinning drastically and stopping the tire rotation), the transmission can go into fail-safe
mode. If this happens, switch “OFF ” the ignition switch for 10 seconds, then switch it “ON” again to return to
the normal shift pattern. Therefore, the customer's vehicle has returned to normal, so handle according to the
“diagnostics flow ” (Refer to AT- 4 5 , "
WORK FLOW" ).
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, this function controls the A/T to make driving possible.
Vehicle Speed Sensor

Signals are input from two systems - from vehicle speed sensor A/T (revolution sensor) installed on the
transmission and from combination meter so normal driving is possible even if there is a malfunction in
one of the systems. And if vehicle speed sensor A/T (revolution sensor) has unusual cases, 5th gear is
prohibited.
Accelerator Pedal Position Sensor

If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM accord-
ing to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow
systems, the engine speed is fixed by ECM to a pre-determined engine speed to make driving possible.
Throttle Position Sensor

If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM accord-
ing to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow
systems, the accelerator opening angle is controlled by the idle signal sent from the ECM which is based
on input indicating either idle condition or off-idle condition (pre-determined accelerator opening) in order
to make driving possible.
PNP Switch

In the unlikely event that a malfunction signal enters the TCM, the position indicator is switched “OFF”, the
starter relay is switched “OFF ” (starter starting is disabled), the back-up lamp relay switched “OFF” (back-
up lamp is OFF) and the position is fixed to the “D” range to make driving possible.
Starter Relay

The starter relay is switched “OFF”. (Starter starting is disabled.)
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above

TROUBLE DIAGNOSISAT-43
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Revision: November 2009 2006 QX56
A/T Interlock

If there is an A/T interlock judgment malfunction, the transmission is fixed in 2nd gear to make driving pos-
sible.
NOTE:
When the vehicle is driven fixed in 2nd gear, a turbine revolution sensor malfunction is displayed,
but this is not a turbine revolution sensor malfunction.

When the coupling pattern below is detected, the fail-safe action corresponding to the pattern is per-
formed.
A/T INTERLOCK COUPLING PATTERN TABLE

: NG X: OK
A/T 1st Engine Braking

When there is an A/T first gear engine brake judgment malfunction, the low coast brake solenoid is
switched “OFF” to avoid the engine brake operation.
Line Pressure Solenoid

The solenoid is switched “OFF” and the line pressure is set to the maximum hydraulic pressure to make
driving possible.
Torque Converter Clutch Solenoid

The solenoid is switched “OFF” to release the lock-up.
Low Coast Brake Solenoid

When a (electrical or functional) malfunction occurs, in order to make driving possible, the engine brake is
not applied in 1st and 2nd gear.
Input Clutch Solenoid

If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF ”, the transmission is
held in 4th gear to make driving possible.
Direct Clutch Solenoid

If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF ”, the transmission is
held in 4th gear to make driving possible.
Front Brake Solenoid

If a (electrical or functional) malfunction occurs with the solenoid “ON”, in order to make driving possible,
the A/T is held in 5th gear; if the solenoid is OFF, 4th gear.
High and Low Reverse Clutch Solenoid

If a (electrical or functional) malfunction occurs with the solenoid either “ON” or “OFF ”, the transmission is
held in 4th gear to make driving possible.
Turbine Revolution Sensor 1 or 2

The control is the same as if there were no turbine revolution sensors, 5th gear is prohibited.
Gear position ATF pressure switch output
Fail-safe function Clutch pressure output pattern after fail-safe func-
tion
SW3 (I/C) SW6
(HLR/
C) SW5
(D/C) SW1
(FR/B) SW2
(LC/B) I/C HLR/C D/C FR/B LC/B L/U
A/T inter-
lock cou-
pling pattern 3rd
–XX –
Held in
2nd gear OFF OFF ON OFF OFF OFF
4th –XX –
Held in
2nd gear OFF OFF ON OFF OFF OFF
5th X X –X
Held in
2nd gear OFF OFF ON OFF OFF OFF

TROUBLE DIAGNOSISAT-47
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Revision: November 2009 2006 QX56
4❏
Perform all road tests and enter checks in required inspection items. AT- 5 4
4-1.Check before engine is started
AT- 5 5
❏ AT- 1 7 9 , "A/T CHECK Indicator Lamp Does Not Come On" .
❏ Perform self-diagnostics Enter checks for detected items. AT- 8 6
❏ AT-96, "DTC U1000 CAN COMMUNICATION LINE"
❏ AT-100, "DTC P0615 START SIGNAL CIRCUIT"
❏ AT-104, "DTC P0700 TCM"
❏ AT-105, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ AT-109, "DTC P0717 TURBINE REVOLUTION SENSOR"
❏ AT- 111 , "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)"
❏ AT-116, "DTC P0725 ENGINE SPEED SIGNAL"
❏ AT-118, "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ AT-120, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ AT-122, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ AT-124, "DTC P1705 THROTTLE POSITION SENSOR"
❏ AT-127, "DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT"
❏ AT-132, "DTC P1721 VEHICLE SPEED SENSOR MTR"
❏ AT-134, "DTC P1730 A/T INTERLOCK"
❏ AT-137, "DTC P1731 A/T 1ST ENGINE BRAKING"
❏ AT-139, "DTC P1752 INPUT CLUTCH SOLENOID VALVE"
❏ AT-141, "DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-143, "DTC P1757 FRONT BRAKE SOLENOID VALVE"
❏ AT-145, "DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION"
❏ AT-147, "DTC P1762 DIRECT CLUTCH SOLENOID VALVE"
❏ AT-149, "DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-151, "DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE"
❏ AT-153, "DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION"
❏ AT-155, "DTC P1772 LOW COAST BRAKE SOLENOID VALVE"
❏ AT-157, "DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION"
❏ AT-159, "DTC P1841 ATF PRESSURE SWITCH 1"
❏ AT-161, "DTC P1843 ATF PRESSURE SWITCH 3"
❏ AT-163, "DTC P1845 ATF PRESSURE SWITCH 5"
❏ AT-165, "DTC P1846 ATF PRESSURE SWITCH 6"
4-2. Idle inspection
AT- 5 5
❏ AT- 1 7 9 , "Engine Cannot Be Started In “P” or “N” Position"
❏ AT- 1 8 0 , "In “P” Position, Vehicle Moves When Pushed"
❏ AT- 1 8 1 , "In “N” Position, Vehicle Moves"
❏ AT- 1 8 2 , "Large Shock (“N” to “D” Position)"
❏ AT- 1 8 6 , "Vehicle Does Not Creep Backward In “R” Position"
❏ AT- 1 8 9 , "Vehicle Does Not Creep Forward In “D” Position"
4-3. Driving tests
AT- 5 6
Part 1
❏ AT- 1 9 1 , "
Vehicle Cannot Be Started From D1"
❏ AT- 1 9 4 , "A/T Does Not Shift: D1 → D2"
❏ AT- 1 9 6 , "A/T Does Not Shift: D2 → D3"
❏ AT- 1 9 8 , "A/T Does Not Shift: D3 → D4"
❏ AT- 2 0 1 , "A/T Does Not Shift: D4 → D5"
❏ AT- 2 0 3 , "A/T Does Not Perform Lock-up"
❏ AT- 2 0 5 , "A/T Does Not Hold Lock-up Condition"
❏ AT- 2 0 7 , "Lock-up Is Not Released"
❏ AT- 2 0 8 , "Engine Speed Does Not Return to Idle"

AT-48
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
44-3Part 2
AT- 5 8
❏ AT-191, "Vehicle Cannot Be Started From D1"
❏ AT-194, "A/T Does Not Shift: D1 → D2"
❏ AT-196, "A/T Does Not Shift: D2 → D3"
❏ AT-198, "A/T Does Not Shift: D3 → D4"
Part 3
AT- 5 9
❏ AT-209, "A/T Does Not Shift: 5th gear → 4th gear"
❏ AT-212, "A/T Does Not Shift: 4th gear → 3rd gear"
❏ AT-213, "A/T Does Not Shift: 3rd gear → 2nd gear"
❏ AT-215, "A/T Does Not Shift: 2nd gear → 1st gear"
❏ AT-218, "Vehicle Does Not Decelerate By Engine Brake"
❏ Perform self-diagnostics Enter checks for detected items. AT- 8 6
❏ AT- 9 6 , "DTC U1000 CAN COMMUNICATION LINE"
❏ AT-100, "DTC P0615 START SIGNAL CIRCUIT"
❏ AT-104, "DTC P0700 TCM"
❏ AT-105, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ AT-109, "DTC P0717 TURBINE REVOLUTION SENSOR"
❏ AT- 111 , "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)"
❏ AT- 11 6 , "DTC P0725 ENGINE SPEED SIGNAL"
❏ AT- 11 8 , "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ AT-120, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ AT-122, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ AT-124, "DTC P1705 THROTTLE POSITION SENSOR"
❏ AT-127, "DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT"
❏ AT-132, "DTC P1721 VEHICLE SPEED SENSOR MTR"
❏ AT-134, "DTC P1730 A/T INTERLOCK"
❏ AT-137, "DTC P1731 A/T 1ST ENGINE BRAKING"
❏ AT-139, "DTC P1752 INPUT CLUTCH SOLENOID VALVE"
❏ AT-141, "DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-143, "DTC P1757 FRONT BRAKE SOLENOID VALVE"
❏ AT-145, "DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION"
❏ AT-147, "DTC P1762 DIRECT CLUTCH SOLENOID VALVE"
❏ AT-149, "DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-151, "DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE"
❏ AT-153, "DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION"
❏ AT-155, "DTC P1772 LOW COAST BRAKE SOLENOID VALVE"
❏ AT-157, "DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION"
❏ AT-159, "DTC P1841 ATF PRESSURE SWITCH 1"
❏ AT-161, "DTC P1843 ATF PRESSURE SWITCH 3"
❏ AT-163, "DTC P1845 ATF PRESSURE SWITCH 5"
❏ AT-165, "DTC P1846 ATF PRESSURE SWITCH 6"
5 ❏
Inspect each system for items found to be NG in the self-diagnostics and repair or replace the malfunction
parts.
6 ❏ Perform all road tests and enter the checks again for the required items. AT- 5 4
7❏
For any remaining NG items, perform the “diagnostics procedure ” and repair or replace the malfunction parts.
See the chart for diagnostics by symptoms. (This chart also contains other symptoms and inspection proce-
dures.) AT- 6 1
8
❏ Erase the results of the self-diagnostics from the TCM. AT- 3 9

TROUBLE DIAGNOSISAT-61
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Revision: November 2009 2006 QX56
Symptom ChartECS00CEN

The diagnostics item numbers show the sequence for inspection. Inspect in order from item 1.

Overhaul and inspect inside the A/T only if A/T fluid condition is NG. Refer to AT- 5 1 , "A/T FLUID
CHECK" .
No. Items Symptom Condition Diagnostic ItemReference
page
1
Shift
Shock Large shock. (
“N ” → “
D ” position)
Refer to AT-182,
"Large Shock (“N” to
“D” Position)" . ON vehicle 1. Engine idle speed
EC-76
2. Engine speed signalAT- 11 6
3. Accelerator pedal position sensorAT-124
4. Control cable adjustmentAT-227
5. ATF temperature sensorAT-127
6. ATF pressure switch 1 and front brake solenoid valveAT-159,
AT-143
7. CAN communication line AT- 9 6
8. Fluid level and stateAT- 5 1
9. Line pressure testAT- 5 2
10. Control valve with TCMAT-230
OFF vehicle11. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 7 , AT- 1 8
.) AT-264
2Shock is too large
when changing D1 →

D
2 . ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. ATF pressure switch 5 and direct clutch solenoid valveAT-163,
AT-147
4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT-109
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT-230
OFF vehicle 10. Direct clutch AT-298
3Shock is too large
when changing D2 →

D
3 . ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT-165,
AT-151
4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT-109
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT-230
OFF vehicle 10. High and low reverse clutch AT-296

AT-62
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
4
Shift
Shock Shock is too large
when changing D3
→
D
4 . ON vehicle1. Accelerator pedal position sensor
AT- 1 2 4
2. Control cable adjustmentAT- 2 2 7
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 6 1,
AT- 1 3 9
4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT- 1 0 9
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT- 2 3 0
OFF vehicle 10. Input clutch AT- 2 8 6
5Shock is too large
when changing D4
→
D
5 . ON vehicle1. Accelerator pedal position sensor
AT- 1 2 4
2. Control cable adjustmentAT- 2 2 7
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 5 9,
AT- 1 4 3

4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT- 1 0 9
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT- 2 3 0
OFF vehicle10. Front brake (brake band)
AT- 2 5 011. Input clutchAT- 2 8 6
6Shock is too large for
downshift when accel-
erator pedal is
pressed. ON vehicle1. Accelerator pedal position sensor
AT- 1 2 4
2. Control cable adjustmentAT- 2 2 7
3. CAN communication line AT- 9 6
4. Engine speed signalAT- 11 6
5. Turbine revolution sensorAT- 1 0 9
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
7. Fluid level and state AT- 5 1
8. Control valve with TCMAT- 2 3 0
OFF vehicle9. Front brake (brake band)
AT- 2 5 0
10. Input clutchAT- 2 8 6
11. High and low reverse clutchAT- 2 9 6AT-
296
12. Direct clutch
AT- 2 9 8
No. ItemsSymptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSISAT-63
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7
Shift
Shock Shock is too large for
upshift when acceler-
ator pedal is released.
ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. Engine speed signal AT- 11 6
4. CAN communication line AT- 9 6
5. Turbine revolution sensorAT-109
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
7. Fluid level and state AT- 5 1
8. Control valve with TCMAT-230
OFF vehicle9. Front brake (brake band)
AT-25010. Input clutchAT-286
11. High and low reverse clutchAT-296
12. Direct clutchAT-298
8Shock is too large for
lock-up. ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. Engine speed signal AT- 11 6
4. CAN communication line AT- 9 6
5. Turbine revolution sensorAT-109
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
7. Torque converter clutch solenoid valve AT- 11 8
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT-230
OFF vehicle 10. Torque converter AT-264
9Shock is too large
during engine brake. ON vehicle
1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. CAN communication line AT- 9 6
4. Fluid level and stateAT- 5 1
5. Control valve with TCMAT-230
OFF vehicle6. Front brake (brake band)
AT-2507. Input clutchAT-286
8. High and low reverse clutchAT-296
9. Direct clutchAT-298
No. ItemsSymptom Condition Diagnostic ItemReference
page

AT-64
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
10
No Up
Shift Gear does not change
from D
1
→ D2 .
Refer to AT-194, "
A/T
Does Not Shift: D1 →
D2" . ON vehicle1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
3. ATF pressure switch 5 and direct clutch solenoid valve AT- 1 6 3,
AT- 1 4 7
4. Line pressure test AT- 5 2
5. CAN communication lineAT- 9 6
6. Control valve with TCMAT- 2 3 0
OFF vehicle 7. Direct clutch AT- 2 9 8
11Gear does not change
from D2
→ D3 .
Refer to AT-196, "
A/T
Does Not Shift: D2 →
D3" . ON vehicle1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valve AT- 1 6 5,
AT- 1 5 1
4. Line pressure test AT- 5 2
5. CAN communication lineAT- 9 6
6. Control valve with TCMAT- 2 3 0
OFF vehicle 7. High and low reverse clutch AT- 2 9 6
12Gear does not change
from D
3
→ D4 .
Refer to AT-198, "
A/T
Does Not Shift: D3 →
D4" . ON vehicle1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
3. ATF pressure switch 3 and input clutch solenoid valve AT- 1 6 1,
AT- 1 3 9
4. ATF pressure switch 1 and front brake solenoid valve AT- 1 5 9,
AT- 1 4 3
5. Line pressure test AT- 5 2
6. CAN communication lineAT- 9 6
7. Control valve with TCMAT- 2 3 0
OFF vehicle 8. Input clutch AT- 2 8 6
13Gear does not change
from D
4
→ D5 .
Refer to AT-201, "
A/T
Does Not Shift: D4 →
D5" . ON vehicle1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
3. ATF pressure switch 1 and front brake solenoid valve AT- 1 5 9,
AT- 1 4 3
4. ATF pressure switch 5 and direct clutch solenoid valve AT- 1 6 3,
AT- 1 4 7
5. Turbine revolution sensor AT- 1 0 9
6. Line pressure test AT- 5 2
7. CAN communication lineAT- 9 6
8. Control valve with TCMAT- 2 3 0
OFF vehicle9. Front brake (brake band)
AT- 2 6 410. Input clutchAT- 2 8 6
No. ItemsSymptom Condition Diagnostic ItemReference
page