Infiniti Q45. Manual - part 63

DTC P1841 ATF PRESSURE SWITCH 1

AT-165

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DTC P1841 ATF PRESSURE SWITCH 1

PFP:25240

Description

NCS000ZG

Fail-safe function to detect front brake clutch solenoid valve condition.

CONSULT-II Reference Value

NCS000ZH

On Board Diagnosis Logic

NCS000ZI

●

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

●

Diagnostic trouble code “P1841 ATF PRES SW 1/CIRC” with CONSULT-II is detected when TCM detects
that actual gear ratio is normal, and relation between gear position and condition of ATF pressure switch 1
is irregular during depressing accelerator pedal. (Other than during shift change.)

Possible Cause

NCS000ZJ

●

ATF pressure switch 1

●

Harness or connectors
(Switch circuit is open or shorted.)

DTC Confirmation Procedure

NCS000ZK

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.

Start engine.

2.

Accelerate vehicle to maintain the following conditions.
ACCELE POSI: 1.5/8 - 2.0/8
SLCT LVR POSI: “D” position 
GEAR: “3” 

Þ

 “4” (FR/B ON/OFF)

Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.

3.

Perform step “2” again.

4.

Turn ignition switch OFF, then perform step “1” to “3” again.

5.

Check “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
If DTC (P1841) is detected, go to 

AT-166, "Diagnostic Procedure"

 .

If DTC (P1757) is detected, go to 

AT-146, "Diagnostic Procedure"

 .

Item name

Condition 

Display value 

ATF PRES SW 1

Front brake engaged. Refer to 

AT-19

 

.

ON

Front brake disengaged. Refer to 

AT-19

 

.

OFF

BCIA0031E

AT-166

DTC P1841 ATF PRESSURE SWITCH 1

Diagnostic Procedure

NCS000ZL

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 

Þ

 4th gear), and confirm

the ON/OFF actuation of the “ATF PRES SW 1”.

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-173, "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.

●

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-225, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

 .

NG

>> Repair or replace damaged parts.

4. 

CHECK DTC

Perform “DTC Confirmation Procedure”. Refer to 

AT-165, "DTC Confirmation Procedure"

 .

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

Item name

Condition 

Display value

ATF PRES SW 1

Front brake engaged. Refer to 

AT-19

 

.

ON

Front brake disengaged. Refer to 

AT-19

 

.

OFF

PCIA0067E

DTC P1843 ATF PRESSURE SWITCH 3

AT-167

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DTC P1843 ATF PRESSURE SWITCH 3

PFP:25240

Description

NCS000ZM

Fail-safe function to detect input clutch solenoid valve condition.

CONSULT-II Reference Value

NCS000ZN

On Board Diagnosis Logic

NCS000ZO

●

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

●

Diagnostic trouble code “P1843 ATF PRES SW 3/CIRC” with CONSULT-II is detected when TCM detects
that actual gear ratio is normal, and relation between gear position and condition of ATF pressure switch 3
is irregular during depressing accelerator pedal. (Other than during shift change.)

Possible Cause

NCS000ZP

●

ATF pressure switch 3

●

Harness or connectors
(Switch circuit is open or shorted.)

DTC Confirmation Procedure

NCS000ZQ

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.

Start engine.

2.

Accelerate vehicle to maintain the following conditions.
ACCELE POSI: 1.5/8 - 2.0/8
SLCT LVR POSI: “D” position 
GEAR: “3” 

Þ

 “4” (I/C ON/OFF) 

Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.

3.

Perform step “2” again.

4.

Turn ignition switch OFF, then perform step “1” to “3” again.

5.

Check “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
If DTC (P1843) is detected, go to 

AT-168, "Diagnostic Procedure"

 .

If DTC (P1752) is detected, go to 

AT-142, "Diagnostic Procedure"

 .

Item name

Condition 

Display value

ATF PRES SW 3

Input clutch engaged. Refer to 

AT-19

 

.

ON

Input clutch disengaged. Refer to 

AT-19

 

.

OFF

BCIA0031E

AT-168

DTC P1843 ATF PRESSURE SWITCH 3

Diagnostic Procedure

NCS000ZR

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 

Þ

 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-173, "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.

●

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-225, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

 .

NG

>> Repair or replace damaged parts.

4. 

CHECK DTC

Perform “DTC Confirmation Procedure”. Refer to 

AT-167, "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-19

 

.

ON

Input clutch disengaged. Refer to 

AT-19

 

.

OFF

PCIA0067E