2004 INFINITI QX56 ECU

DTC P0725 ENGINE SPEED SIGNAL
AT-115
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Revision: August 20072004 QX56
DTC P0725 ENGINE SPEED SIGNALPFP:24825
DescriptionUCS002E1
The engine speed signal is sent from the ECM to the TCM.
CONSULT-II Reference ValueUCS002E2
On Board Diagnosis LogicUCS002E3

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

Diagnostic trouble code “ENGINE SPEED SIG” with CONSULT-II is detected when TCM does not receive
the ignition signal from ECM during engine cranking or running.
Possible CauseUCS002E4
Harness or connectors
(The ECM to the TCM circuit is open or shorted.)
DTC Confirmation ProcedureUCS002E5
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” and select “DATA MONITOR” mode for
“A/T” with CONSULT-II.
2. Start engine and maintain the following conditions for at least 10
consecutive seconds.
VHCL SPEED SE: 10 km/h (6 MPH) or more
ACCELE POSI: More than 1/8
Selector lever: “D” position
3. If DTC is detected, go to AT - 11 5 , "
Diagnostic Procedure" .
Diagnostic ProcedureUCS002E6
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis.Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
Item name Condition Display value (rpm)
ENGINE SPEED Engine running Closely matches the tachometer reading.
BCIA0030E

AT-116
DTC P0725 ENGINE SPEED SIGNAL
Revision: August 20072004 QX56
2. CHECK DTC WITH TCM
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. While monitoring engine speed, check for engine speed change
corresponding to wide-open throttle position signal.
With GST
Follow the procedure “With CONSULT-II”.
OK or NG
OK >> GO TO 3.
NG >> Check the ignition signal circuit.

Refer to EC-583, "IGNITION SIGNAL" .
3. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 4.
NG >> GO TO 6.
4. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-115, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 5.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-241, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
6. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
Item name Condition Display value (rpm)
ENGINE SPEED Engine running Closely matches the tachometer reading.
PCIA0041E

AT-118
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
Revision: August 20072004 QX56
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVEPFP:31940
DescriptionUCS002E7

The torque converter clutch solenoid valve is activated, with the gear in D4 , D5 by the TCM in response
to signals sent from the vehicle speed sensor and accelerator pedal position sensor (throttle position sen-
sor). Torque converter clutch piston operation will then be controlled.

Lock-up operation, however, is prohibited when A/T fluid temperature is too low.

When the accelerator pedal is depressed (less than 1/8) in lock-up condition, the engine speed should not
change abruptly. If there is a big jump in engine speed, there is no lock-up.
CONSULT-II Reference ValueUCS002E8
On Board Diagnosis LogicUCS002E9

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “TCC SOLENOID/CIRC” with CONSULT-II or P0740 without CONSULT-II is
detected under the following conditions.
–When TCM detects an improper voltage drop when it tries to operate the solenoid valve.
–When TCM detects as irregular by comparing target value with monitor value.
Possible CauseUCS002EA

Torque converter clutch solenoid valve

Harness or connectors
(The solenoid circuit is open or shorted.)
DTC Confirmation ProcedureUCS002EB
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 “DATA MONITOR” mode for “ENGINE” with CONSULT-II.
3. Start engine and maintain the following conditions for at least 5
consecutive seconds.
VHCL SPEED SE: 80 km/h (50 MPH) or more
ACCELE POS: 0.5/8 - 1.0/8
SELECTOR LEVER: “D” position
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
4. If DTC is detected go to AT-119, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.) (A)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4
When performing lock-up 0.4 - 0.6
BCIA0030E

DTC P1702 TRANSMISSION CONTROL MODULE (RAM)
AT-127
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Revision: August 20072004 QX56
DTC P1702 TRANSMISSION CONTROL MODULE (RAM)PFP:31036
DescriptionUCS002EP
The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The
TCM controls the A/T.
On Board Diagnosis LogicUCS002EQ

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

Diagnostic trouble code “TCM·RAM” with CONSULT-II is detected when TCM memory RAM is malfunc-
tioning.
Possible CauseUCS002ER
TCM.
DTC Confirmation ProcedureUCS002ES
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 “DATA MONITOR” mode for “A/T” with CONSULT-II.
3. Start engine.
4. Run engine for at least 2 consecutive seconds at idle speed.
5. If DTC is detected, go to AT - 1 2 7 , "
Diagnostic Procedure" .
Diagnostic ProcedureUCS002ET
1. CHECK DTC
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform “DTC Confirmation Procedure”, AT-127, "
DTC Confir-
mation Procedure" .
Is the
“TCM·RAM” displayed again?
YES >> Replace the control valve with TCM. Refer to AT-241,
"Control Valve With TCM and A/T Fluid Temperature
Sensor 2" .
NO >>INSPECTION END
BCIA0030E
BCIA0031E

AT-128
DTC P1703 TRANSMISSION CONTROL MODULE (ROM)
Revision: August 20072004 QX56
DTC P1703 TRANSMISSION CONTROL MODULE (ROM)PFP:31036
DescriptionUCS002EU
The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The
TCM controls the A/T.
On Board Diagnosis LogicUCS002EV

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

Diagnostic trouble code “TCM·ROM” with CONSULT-II is detected when TCM memory ROM is malfunc-
tioning.
Possible CauseUCS002EW
TCM.
DTC Confirmation Procedure UCS002EX
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 to “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for A/T with CONSULT-II.
3. Start engine.
4. Run engine for at least 2 consecutive seconds at idle speed.
5. If DTC is detected, go to AT-128, "
Diagnostic Procedure" .
Diagnostic ProcedureUCS002EY
1. CHECK DTC
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform “DTC Confirmation Procedure”, AT-128, "
DTC Confir-
mation Procedure" .
Is the
“TCM·ROM” displayed again?
YES >> Replace the control valve with TCM. Refer to AT-241,
"Control Valve With TCM and A/T Fluid Temperature
Sensor 2" .
NO >>INSPECTION END
BCIA0030E
BCIA0031E

AT-130
DTC P1705 THROTTLE POSITION SENSOR
Revision: August 20072004 QX56
2. CHECK DTC WITH TCM
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 “ACCLE
POSI” and “THROTTLE POSI”.
Check engine speed changes according to throttle position.
4. Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-II. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC
RESULT MODE" .
With GST
Follow the procedure “With CONSULT-II”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. CHECK DTC WITH ECM
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS” mode for “ENGINE” with CON-
SULT-II. Refer to EC-103, "
CONSULT-II Function" .
With GST
Follow the procedure “With CONSULT-II”.
OK or NG
OK >> GO TO 4.
NG >> Check the DTC detected item. Refer to EC-103, "
CON-
SULT-II Function" .

If CAN communication line is detected, go to AT-103,
"DTC U1000 CAN COMMUNICATION LINE" .
4. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-129, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> Replace the control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
Item name Condition Display value
(Approx.)
ACCLE POSIReleased accelerator pedal. 0.0/8
Fully depressed accelerator pedal. 8/8
THROTTLE POSIReleased accelerator pedal. 0.0/8
Fully depressed accelerator pedal. 8/8
PCIA0070E
BCIA0031E

AT-132
DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002FA
1. CHECK A/T FLUID TEMPERATURE SENSOR 1 SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. Read out the value of “ATF TEMP SE 1”.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
2. CHECK A/T FLUID TEMPERATURE SENSOR 2 SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. Read out the value of “ATF TEMP SE 2”.
OK or NG
OK >> GO TO 8.
NG >> GO TO 3.
3. CHECK A/T FLUID TEMPERATURE SENSOR 2
Check A/T fluid temperature sensor 2. Refer to AT-133, "
Component Inspection" .
OK or NG
OK >> GO TO 4.
NG >> Replace the A/T fluid temperature sensor 2. Refer to AT-249, "
A/T FLUID TEMPERATURE SEN-
SOR 2 REMOVAL AND INSTALLATION" .
4. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 5.
NG >> GO TO 7.
5. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-131, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 6.
Item name Condition °C (°F) Display value (Approx.)
ATF TEMP SE 1 0 (32) - 20 (68) - 80 (176) 3.2 - 2.5 - 0.8 V
PCIA0039E
Item name Condition °C (°F) Display value (Approx.)
ATF TEMP SE 2 0 (32) - 20 (68) - 80 (176) 3.2 - 2.4 - 0.65 V
PCIA0039E

AT-134
DTC P1716 TURBINE REVOLUTION SENSOR
Revision: August 20072004 QX56
DTC P1716 TURBINE REVOLUTION SENSORPFP:31935
DescriptionUCS002FC
The turbine revolution sensor detects input shaft rpm (revolutions per minute). It is located on the input side of
the automatic transmission. Monitors revolution of sensor 1 and sensor 2 for non-standard conditions.
CONSULT-II Reference ValueUCS002FD
On Board Diagnosis LogicUCS002FE

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “TURBINE REV S/CIRC” with CONSULT-II or P1716 without CONSULT-II is
detected under the following conditions.
–When TCM does not receive the proper voltage signal from the sensor.
–When TCM detects an irregularity only at position of 4th gear for turbine revolution sensor 2.
Possible CauseUCS002FF

Harness or connectors
(The sensor circuit is open or shorted.)

Turbine revolution sensor 1, 2
DTC Confirmation ProcedureUCS002FG
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 “DATA MONITOR” mode for “A/T” with CONSULT-II.
3. Start engine and maintain the following conditions for at least 5
consecutive seconds.
VHCL SPEED SE: 40 km/h (25 MPH) or more
ENGINE SPEED: 1,500 rpm or more
ACCELE POS: 0.5/8 or more
Selector lever: “D” position
Gear position (Turbine revolution sensor 1): 4th or 5th posi-
tion
Gear position (Turbine revolution sensor 2): All position
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions required for this test.
4. If DTC is detected, go to AT-135, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (rpm)
TURBINE REV During driving (lock-up ON) Approximately matches the engine speed.
BCIA0030E