2005 INFINITI FX35 AUX

DTC P1721 VEHICLE SPEED SENSOR MTR AT-143
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DTC P1721 VEHICLE SPEED SENSOR MTRPFP:24814
DescriptionACS002OG
The vehicle speed sensor·MTR signal is transmitted from combination meter to TCM by CAN communication
line. The signal functions as an auxiliary device to the revolution sensor when it is malfunctioning. The TCM
will then use the vehicle speed sensor·MTR signal.
CONSULT-II Reference ValueACS003KE
On Board Diagnosis LogicACS002OH

This is not an OBD-II self-diagnostic item.

Diagnostic trouble code “P1721 VHE SPD SE/CIR·MTR” with CONSULT-II is detected when TCM does
not receive the proper vehicle speed sensor MTR signal (input by CAN communication) from combination
meter.
Possible CauseACS002OI

Harness or connectors
(Sensor circuit is open or shorted.)
DTC Confirmation ProcedureACS002OJ
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 procedure to confirm the malfunction is eliminated.
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. Touch “START”.
4. Start engine and maintain the following conditions for at least 5 consecutive seconds.
ACCELE POSI: 1.0/8 or less
VHCL SPEED SE: 30 km/h (17 MPH) or more
5. If DTC is detected, go to AT- 1 4 4 , "
Diagnostic Procedure" .
Item name Condition Display value (Approx.) (km/h)
VHCL/S SE·MTR During driving Approximately matches the speedometer reading.
BCIA0031E

ATC-2Revision: 2005 July 2005 FX
MODE SWITCH ................................................
... 35
FAN SWITCH ................................................... ... 35
DUAL SWITCH (WITH LEFT AND RIGHT VEN-
TILATION TEMPERATURE SEPARATELY
CONTROL SYSTEM) ....................................... ... 35
Fail-safe Function ................................................ ... 36
Discharge Air Flow .............................................. ... 37
System Description .............................................. ... 38
SWITCHES AND THEIR CONTROL FUNCTION ... 38
CAN Communication System Description ........... ... 39
TROUBLE DIAGNOSIS ......................................... ... 40
CONSULT-II Function (BCM) ............................... ... 40
CONSULT-II BASIC OPERATION .................... ... 40
DATA MONITOR ............................................... ... 41
How to Perform Trouble Diagnosis for Quick and
Accurate Repair ................................................... ... 42
WORK FLOW ................................................... ... 42
SYMPTOM TABLE ........................................... ... 42
Component Parts and Harness Connector Location ... 43
ENGINE COMPARTMENT ............................... ... 43
PASSENGER COMPARTMENT ....................... ... 44
Schematic ............................................................ ... 45
Wiring Diagram —A/C— ...................................... ... 46
Auto Amp. Terminals and Reference Value ......... ... 51
PIN CONNECTOR TERMINAL LAYOUT ......... ... 51
TERMINALS AND REFERENCE VALUE FOR
UNIFIED METER AND A/C AMP. ..................... ... 51
Self-diagnosis Function ....................................... ... 53
DESCRIPTION ................................................. ... 53
FUNCTION CONFIRMATION PROCEDURE ... ... 54
AUXILIARY MECHANISM: TEMPERATURE
SETTING TRIMMER ........................................ ... 59
AUXILIARY MECHANISM: FOOT POSITION
SETTING TRIMMER ........................................ ... 60
AUXILIARY MECHANISM: INLET PORT MEM-
ORY FUNCTION .............................................. ... 60
Operational Check ............................................... ... 61
CHECKING MEMORY FUNCTION .................. ... 61
CHECKING BLOWER ...................................... ... 61
CHECKING DISCHARGE AIR ......................... ... 61
CHECKING INTAKE AIR .................................. ... 62
CHECKING TEMPERATURE DECREASE ...... ... 62
CHECKING TEMPERATURE INCREASE ....... ... 62
CHECK A/C SWITCH ....................................... ... 62
CHECKING AUTO MODE ................................ ... 63
Power Supply and Ground Circuit for Auto Amp. ... 63 INSPECTION FLOW ........................................ ... 63
COMPONENT DESCRIPTION ......................... ... 64
DIAGNOSIS PROCEDURE FOR A/C SYSTEM ... 64
LAN System Circuit ............................................. ... 66
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT ... 66
Mode Door Motor Circuit ..................................... ... 70
INSPECTION FLOW ........................................ ... 70
SYSTEM DESCRIPTION ................................. ... 71
COMPONENT DESCRIPTION ......................... ... 72
DIAGNOSIS PROCEDURE FOR MODE DOOR
MOTOR ............................................................ ... 72
Air Mix Door Motor Circuit ................................... ... 73
INSPECTION FLOW ........................................ ... 73 SYSTEM DESCRIPTION ..................................
... 74
COMPONENT DESCRIPTION ......................... ... 75
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR
MOTOR ............................................................. ... 75
Air Mix Door Motor PBR Circuit ........................... ... 75
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR
MOTOR PBR .................................................... ... 75
Intake Door Motor Circuit ..................................... ... 76
INSPECTION FLOW ......................................... ... 76
SYSTEM DESCRIPTION .................................. ... 77
COMPONENT DESCRIPTION ......................... ... 78
DIAGNOSIS PROCEDURE FOR INTAKE DOOR
MOTOR ............................................................. ... 78
Blower Motor Circuit ............................................. ... 79
INSPECTION FLOW ......................................... ... 79
SYSTEM DESCRIPTION .................................. ... 80
COMPONENT DESCRIPTION ......................... ... 81
DIAGNOSIS PROCEDURE FOR BLOWER
MOTOR ............................................................. ... 81
COMPONENT INSPECTION ............................ ... 83
Magnet Clutch Circuit ........................................... ... 84
INSPECTION FLOW ......................................... ... 84
SYSTEM DESCRIPTION .................................. ... 85
DIAGNOSIS PROCEDURE FOR MAGNET
CLUTCH ........................................................... ... 85
COMPONENT INSPECTION ............................ ... 90
Insufficient Cooling ............................................... ... 91
INSPECTION FLOW ......................................... ... 91
PERFORMANCE TEST DIAGNOSIS ............... ... 93
PERFORMANCE CHART ................................. ... 95
TROUBLE DIAGNOSIS FOR UNUSUAL PRES-
SURE ................................................................ ... 96
DIAGNOSIS PROCEDURE FOR INSUFFI-
CIENT COOLING .............................................. ... 98
Insufficient Heating .............................................. .100
INSPECTION FLOW ......................................... .100
Noise .................................................................... .101
INSPECTION FLOW ......................................... .101
Self-diagnosis ...................................................... .102
INSPECTION FLOW ......................................... .102
Memory Function ................................................. .103
INSPECTION FLOW ......................................... .103
Ambient Sensor Circuit ........................................ .104
COMPONENT DESCRIPTION ......................... .104
AMBIENT TEMPERATURE INPUT PROCESS .104
DIAGNOSIS PROCEDURE FOR AMBIENT
SENSOR ........................................................... .104
COMPONENT INSPECTION ............................ .106
In-vehicle Sensor Circuit ...................................... .107
COMPONENT DESCRIPTION ......................... .107
DIAGNOSIS PROCEDURE FOR IN-VEHICLE
SENSOR ........................................................... .108
COMPONENT INSPECTION ............................ .109
Sunload Sensor Circuit ........................................ .110
COMPONENT DESCRIPTION ......................... .110
SUNLOAD INPUT PROCESS .......................... .110
DIAGNOSIS PROCEDURE FOR SUNLOAD
SENSOR ........................................................... .110

TROUBLE DIAGNOSIS ATC-53
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Revision: 2005 July 2005 FX
Self-diagnosis FunctionAJS0014P
DESCRIPTION
The self-diagnosis system diagnoses sensors, door motors, blower motor, etc. by system line. Refer to appli-
cable sections (items) for details. Shifting from usual control to the self-diagnosis system is accomplished by
starting the engine (turning the ignition switch ON) and pressing OFF switch for at least 5 seconds. The OFF
switch must be pressed within 10 seconds after starting the engine (ignition switch is turned ON). This system
will be canceled by either pressing AUTO switch or turning the ignition switch OFF. Shifting from one step to
another is accomplished by means of pressing temperature switch (driver side), as required.
Shifting from STEP-5 to AUXILIARY MECHANISM is accomplished by means of pressing (fan) UP switch.
RJIA1967E

TROUBLE DIAGNOSIS ATC-55
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6. STEP-4: OPERATION OF EACH DOOR MOTOR IS CHECKED
1. Press temperature (UP) switch (driver side).
2. Press (DEF) switch. Code No. of each door motor test is indicated on the display.
>> GO TO 7.
7. CHECK ACTUATORS
Refer to the following chart and confirm discharge air flow, air tem-
perature, blower motor duty ratio and compressor operation.
Checks must be made visually, by listening to any noise, or by touching air outlets with hand, etc. for improper
operation.
*1: FOOT position during automatic control. Refer to AT C - 6 0 , "
AUXILIARY MECHANISM: FOOT POSITION
SETTING TRIMMER" .
OK or NG
OK >> GO TO 8.
NG >>

Air outlet does not change.
Go to Mode Door Motor Circuit. Refer to AT C - 7 0 , "
Mode Door Motor Circuit" .

Intake door does not change.
Go to Intake Door Motor Circuit. Refer to AT C - 7 6 , "
Intake Door Motor Circuit" .

Blower motor operation is malfunctioning.
Go to Blower Motor Circuit. Refer to AT C - 7 9 , "
Blower Motor Circuit" .

Magnet clutch does not engage.
Go to Magnet Clutch Circuit. Refer to AT C - 8 4 , "
Magnet Clutch Circuit" .

Discharge air temperature does not change.
Go to Air Mix Door Motor Circuit. Refer to AT C - 7 3 , "
Air Mix Door Motor Circuit" .
RJIA1968E
SJIA0302E
Code No. 414243444546
Mode door position VENT B/L 1 B/L 2 FOOT
*1D/F DEF
Intake door position REC REC 20% FRE FRE FRE FRE
Air mix door position FULL COLD FULL COLD FULL HOT FULL HOT FULL HOT FULL HOT
Blower motor duty ratio 37% 91% 65% 65% 65% 91%
Compressor ON ON OFF OFF ON ON
Electronic control valve
(ECV) duty ratio 100% 100% 0% 0% 50% 100%

ATC-58
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
14. CHECK MALFUNCTIONING DOOR MOTOR POSITION SWITCH
Mode and/or intake door motor PBR(s) is/are malfunctioning.
(If two or more mode or intake doors are out of order, corresponding code numbers blink respectively twice.)
*1: If mode door motor harness connector is disconnected, the following display pattern will appear.
31 →32 →33 →34 →35 →36 →Return to 31
*2: If intake door motor harness connector is disconnected, the following display pattern will appear.
37 →38 →39 →Return to 37
*3: FOOT position during automatic control. Refer to AT C - 6 0 , "
AUXILIARY MECHANISM: FOOT POSITION
SETTING TRIMMER" .
*4: AT C - 7 2 , "
DIAGNOSIS PROCEDURE FOR MODE DOOR MOTOR" .
*5: AT C - 7 8 , "
DIAGNOSIS PROCEDURE FOR INTAKE DOOR MOTOR" .
>> INSPECTION END
Code No. *1 *2Mode or intake door position Reference page
31 VENT
Mode door motor *4
32 B/L 1
33 B/L 2
34 FOOT*
3
35 D/F
36 DEF
37 FRE
Intake door motor *5
38 20% FRE
39 REC
RJIA0228E

TROUBLE DIAGNOSIS ATC-59
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AUXILIARY MECHANISM: TEMPERATURE SETTING TRIMMER
The trimmer compensates for differences in range of ±3°C ( ±6°F) between temperature setting (displayed dig-
itally) and temperature felt by customer.
Operating procedures for this trimmer are as follows:
1. Begin self-diagnosis STEP-5 mode. Refer to AT C - 5 3 , "
Self-diagnosis Function" .
2. Press (fan) UP switch to set system in auxiliary mode.
3. Display shows 61 in auxiliary mechanism. It takes approximately 3 seconds.
4. Press temperature switch (driver side) as desired. Temperature will change at a rate of 0.5 °C (1.0 °F) each
time a switch is pressed.
CAUTION:
A decimal point is not indicated when the display shows “ °C”.
When battery cable is disconnected, trimmer operation is canceled. Temperature set becomes that of initial
condition, i.e. 0 °C (0 °F).
RJIA1970E

ATC-60
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
AUXILIARY MECHANISM: FOOT POSITION SETTING TRIMMER
Wind distribution ratio in FOOT mode can be set.
Operating procedures for this trimmer are as follows:
1. Begin self-diagnosis STEP-5 mode. Refer to AT C - 5 3 , "
Self-diagnosis Function" .
2. Press (fan) UP switch to set system in auxiliary mode.
3. Display shows 61 in auxiliary mechanism. It takes approximately 3 seconds.
4. Press the mode switch as desired.
AUXILIARY MECHANISM: INLET PORT MEMORY FUNCTION
When ignition switch is turned from OFF to ON, inlet port can be set to AUTO or manual.
Operating procedures for this trimmer are as follows:
1. Begin self-diagnosis STEP-5 mode. Refer to AT C - 5 3 , "
Self-diagnosis Function" .
2. Press (fan) UP switch to set system in auxiliary mode.
3. Display shows 61 in auxiliary mechanism. It takes approximately 3 seconds.
4. Press the recirculation (REC) and fresh (FRE) switch as desired.
RJIA1971E
Switch LED status of
REC/FRE switch Setting status Setting changeover method
REC ON Manual REC status is memorized. (Initial setting)
REC SW: ON
OFF AUTO control
FRE ON Manual FRE status is memorized.
FRE SW: ON
OFF AUTO control (Initial setting)

ATC-92
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
*1ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *2
ATC-73, "
Air Mix Door Motor Circuit"*3ATC-95, "Test Reading"
*4 ATC-59, "AUXILIARY MECHA-
NISM: TEMPERATURE SETTING
TRIMMER"
*5ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13. *6
ATC-66, "
LAN System Circuit"
*7 ATC-79, "Blower Motor Circuit"*8ATC-84, "Magnet Clutch Circuit"*9ATC-93, "PERFORMANCE TEST
DIAGNOSIS"
*10 ATC-61, "Operational Check"*11AT C - 7 , "CONTAMINATED REFRIG-
ERANT"
*12EM-15, "Checking Drive Belts"
(VQ35DE) or EM-173, "
Checking
Drive Belts" (VK45DE)
*13 EC-467, "
SYSTEM DESCRIPTION"
(VQ35DE) or EC-1213, "
SYSTEM
DESCRIPTION" (VK45DE)