2009 INFINITI QX56 ESP

TM-88
< COMPONENT DIAGNOSIS >
P1772 LOW COAST BRAKE SOLENOID
P1772 LOW COAST BRAKE SOLENOID
DescriptionINFOID:0000000003771963
Low coast brake solenoid valve is turned “ON” or “OFF” by the TCM in response to signals sent from the trans-
mission range switch, output speed sensor and accelerato r pedal position sensor (throttle position sensor).
Gears will then be shifted to the optimum position.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000003771964
On Board Diagn osis LogicINFOID:0000000003771965
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P1772” with CONSULT-III is detected when TCM detects an improper voltage drop
when it tries to operate the solenoid valve.
Possible CauseINFOID:0000000003771966
 Harness or connectors (The solenoid circuit is open or shorted.)
 Low coast brake solenoid valve
DTC Confirmation ProcedureINFOID:0000000003771967
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “ENGINE” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5 consecutive seconds.
SLCT LVR POSI: “1” or “2”
GEAR: “1st” or “2nd” (LC/B ON/OFF)
5. If DTC is detected, go to TM-88, "Diagnosis Procedure"
.
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000003771968
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Turn ignition switch “ON”.
2. Select “SELECTION FROM MENU” in “DATA MONI TOR” mode for “TRANSMISSION” with CONSULT-III.
3. Start the engine.
4. Read out the value of “ON OFF SOL” while driving.
OK or NG
OK >> GO TO 4.
Item name Condition Display value
ON OFF SOL Low coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
OFF
Item name Condition Display value
ON OFF SOLLow coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
OFF
Revision: December 20092009 QX56

TM-90
< COMPONENT DIAGNOSIS >
P1774 LOW COAST BRAKE SOLENOID
P1774 LOW COAST BRAKE SOLENOID
DescriptionINFOID:0000000003771969
 Low coast brake solenoid valve is turned “ON” or “OFF” by the TCM in response to signals sent from the
transmission range switch, output speed sensor and accele rator pedal position sensor (throttle position sen-
sor). Gears will then be shifted to the optimum position.
 This is not only caused by electrical malfunction (cir cuits open or shorted) but also by mechanical malfunc-
tion such as control valve sticking, improper solenoid valve operation.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000003771970
On Board Diagn osis LogicINFOID:0000000003771971
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P1774” with CONSULT-III is detected under the following conditions.
- When TCM detects that actual gear ratio is irr egular, and relation between gear position and condition of
ATF pressure switch 2 is irregular during depressing accelerator pedal. (Other than during shift change)
- When TCM detects that relation between gear position and condition of ATF pressure switch 2 is irregular
during releasing accelerator pedal. (Other than during shift change)
Possible CauseINFOID:0000000003771972
 Harness or connectors
(The solenoid and switch circuits are open or shorted.)
 Low coast brake solenoid valve
 ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000003771973
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Start engine.
2. Accelerate vehicle to maintain the following conditions.
SLCT LVR POSI: “1” or “2” position
GEAR: “1st” or “2nd” (LC/B ON/OFF)
3. Perform step “2” again.
4. Turn ignition switch “OFF”, then perform step “1” to “3” again.
5. Check “SELF-DIAG RESULTS” mode for “TRANS MISSION” with CONSULT-III. If DTC (P1774) is
detected, refer to TM-90, "Diagnosis Procedure"
.
If DTC (P1772) is detected, go to TM-88, "Diagnosis Procedure"
.
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000003771974
1.CHECK INPUT SIGNALS
Item name Condition Display value
ON OFF SOLLow coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
OFF
ATF PRES SW 2 Low coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
OFF
Revision: December 20092009 QX56

TM-102
< COMPONENT DIAGNOSIS >
A/T SHIFT LOCK SYSTEM
 Check operation by applying battery voltage to A/T shift selectorterminal 9 and ground to terminal 10.
CAUTION:
Be sure to apply the voltage of the correct polarity to the
respective terminals. Otherwise, the part may be damaged.
PARK POSITION SWITCH
 Check continuity between terminals of the A/T shift selector.
DETENT SWITCH
 Check continuity between terminals of the A/T shift selector.
KEY LOCK SOLENOID
Key lock
 Check operation by applying battery voltage to key switch and key lock solenoid terminal 6 and ground to terminal 5.
CAUTION:
Be careful not to cause burnout of the harness.
Key unlock
AWDIA0700ZZ
Condition Terminal No. Continuity
When selector lever is “P” position. 5 - 6No
When selector lever is not “P” position. Yes
AWDIA0567ZZ
Condition Terminal No. Continuity
When selector lever is “P” position. 3 - 4No
When selector lever is not “P” position. Yes
AWDIA0568ZZ
AWDIA0544ZZ
Revision: December 20092009 QX56

TM-176
< PRECAUTION >
PRECAUTIONS
 All parts should be carefully cleaned with a general purpose, non-flammable solvent before inspection orreassembly.
 Gaskets, seals and O-rings should be replaced any time the transmission is disassembled.
 It is very important to perform functional tests whenever they are indicated.
 The valve body contains precision parts and requires extreme care when parts are removed and serviced. Place disassembled valve body parts in order for easier and proper assembly. Care will also prevent springs
and small parts from becoming scattered or lost.
 Properly installed valves, sleeves, plugs, etc. will s lide along bores in valve body under their own weight.
 Before assembly, apply a coat of recommended ATF to all parts. Apply petroleum jelly to protect O-rings and
seals, or hold bearings and washers in place during assembly. Do not use grease.
 Extreme care should be taken to avoid damage to O-rings, seals and gaskets when assembling.
 Clean or replace ATF cooler if excessive foreign material is found in oil pan or clogging strainer. Refer to TM-
183, "A/T Fluid Cooler Cleaning".
 After overhaul, refill the transmission with new ATF.
 When the A/T drain plug is removed, only some of the fluid is drained. Old A/T fluid will remain in torque con- verter and ATF cooling system.
Always follow the procedures under “Changing A/T Fluid” in the AT section when changing A/T fluid. Refer to
TM-181, "Changing the A/T Fluid (ATF)"
.
Service Notice or PrecautionINFOID:0000000003772016
ATF COOLER SERVICE
 If A/T fluid contains fictional material (clutches, bands, etc.), or if an A/T is repaired, overhauled, or replaced,
inspect and clean the A/T fluid cooler mounted in the radiat or or replace the radiator. Flush cooler lines with
cleaning solvent and compressed air after repair. For A/T fluid cooler cleaning procedure, refer to TM-183,
"A/T Fluid Cooler Cleaning". For radiator replacement, refer to CO-15, "Removal and Installation".
CHECKING AND CHANGING A/T FLUID
 Increase ATF oil temperature to 80 °C (176 °F) first, then check and adjust oil level at 65 °C (149 °F).
NOTE:
The A/T has both water cooling and air cooling systems . The air cooling system has a bypass valve. When
ATF oil temperature is at or below 50 °C (122 °F), it does not flow through the air cooled system. If A/T oil
level is adjusted without flow throughout the entir e system, the level will be 10mm lower than required.
Therefore, all piping should be filled with oil when adjusting level.
OBD-II SELF-DIAGNOSIS
 A/T self-diagnosis is performed by the TCM in combination with the ECM. Refer to the table on TM-32,
"CONSULT-III Function (TRANSMISSION)" for the indicator used to display each self-diagnostic result.
 The self-diagnostic results indicated by the MIL ar e automatically stored in both the ECM and TCM memo-
ries.
Always perform the procedure on TM-30, "OBD-II Diagnostic Trouble Code (DTC)"
to complete the
repair and avoid unnecessary blinking of the MIL.
For details of OBD-II, refer to TM-30
.
 Certain systems and components, especially those related to OBD, may use the new style slide-
locking type harness connector. For descrip tion and how to disconnect, refer to PG-68
.
Revision: December 20092009 QX56

TM-194
< ON-VEHICLE MAINTENANCE >
ROAD TEST
When the transmission changes speed D3 → D4, return the accelerator pedal.
Does the A/T shift-up D3
→ D4 and apply the engine brake?
YES >> 1. Stop the vehicle. 2. See TM-194, "Cruise Test - Part 3"
.
NO >> Enter a check mark at “Vehicle Does Not Shift: D3 → D4” on the diagnostics worksheet, then con-
tinue the road test.
Cruise Test - Part 3INFOID:0000000003772031
1.CHECK SHIFT-DOWN
During D
5 driving, move gear selector from D → 4 → 3 → 2 → 1.
With CONSULT-III
Read the gear position.
Is downshifting correctly performed?
YES >> GO TO 2.
NO >> Enter a check mark at “Vehicle does not shift” at the corresponding position (5th → 4th, 4th → 3rd,
3rd → 2nd, 2nd → 1st) on the diagnostics worksheet, then continue the road test.
2.CHECK ENGINE BRAKE
Does engine braking effectively reduce speed in 1
1 position?
YES >> 1. Stop the vehicle. 2. Carry out the self-diagnostics. Refer to TM-32, "CONSULT-III Function (TRANSMISSION)"
.
NO >> Enter a check mark at “Vehicle Does Not Decelerate By Engine Brake” on the diagnostics work- sheet, then continue trouble diagnosis.
Vehicle Speed When Shifting GearsINFOID:0000000003772032
Refer to TM-290, "Vehicle Speed at Which Gear Shifting Occurs".
Vehicle Speed When Performing a nd Releasing Complete Lock-upINFOID:0000000003772033
Refer to TM-291, "Vehicle Speed at Which Lock-up Occurs/Releases".
Revision: December 20092009 QX56