P0840

DTC P0840 TRANSMISSION FLUID PRESSURE SENSOR A CIRCUIT (SEC PRESSURE SENSOR)

Description
- The transmission fluid pressure sensor A (secondary pressure sensor) detects secondary pressure of CVT and sends TCM the signal.

CONSULT-III Reference Value:

On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P0840 TR PRS SENS/A CIRC" with CONSULT-III is detected when TCM detects an improper voltage drop when it receives the sensor signal.

Possible Cause
- Transmission fluid pressure sensor A (Secondary pressure sensor)
- Harness or connectors
(Switch circuit is open or shorted.)

DTC Confirmation Procedure

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-III
1. Turn ignition switch ON and select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
2. Make sure that output voltage of line temperature sensor is within the range below.
ATF TEMP SEN: 1.0 - 2.0 V
If out of range, drive the vehicle to decrease the voltage (warm up the fluid) or stop engine to increase the voltage (cool down the fluid)
3. Start engine and wait for at least 5 consecutive seconds.
4. If DTC is detected, go to CVT-111, "Diagnostic Procedure".

WITH GST
Follow the procedure "WITH CONSULT-III".

Wiring Diagram - CVT - SECPS

CVT-SECPS-01:

TCM TERMINALS AND REFERENCE VALUES
Refer to CVT-44, "TCM Input/Output Signal Reference Value". Pinout Values and Diagnostic Parameters

Diagnostic Procedure

1.CHECK INPUT SIGNAL

With CONSULT-III
1. Start engine.
2. Select "ECU INPUT SIGNALS" in "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
3. Start vehicle and read out the value of "SEC HYDR SEN".





Without CONSULT-III
1. Start engine.
2. Check voltage between TCM connector terminal and ground.





OK or NG
OK >> GO TO 5.
NG >> GO TO 2.

2.CHECK HARNESS BETWEEN TCM AND TRANSMISSION FLUID PRESSURE SENSOR A (SECONDARY PRESSURE SENSOR)
1. Turn ignition switch OFF.
2. Disconnect TCM connector (A) and CVT unit harness connector (B).








3. Check continuity between TCM connector (A) terminal and CVT unit harness connector (B) terminal.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground and short to power harness or connectors.

3.CHECK HARNESS BETWEEN TCM AND CVT UNIT HARNESS CONNECTOR (SENSOR POWER AND SENSOR GROUND)
1. Turn ignition switch OFF.
2. Disconnect TCM connector (A) and CVT unit harness connector (B).








3. Check continuity between TCM connector (A) terminals and CVT unit harness connector (B) terminals.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.

4.CHECK SENSOR POWER AND SENSOR GROUND
1. Turn ignition switch ON.
2. Disconnect CVT unit harness connector.
3. Check voltage between CVT unit harness connector terminal.





OK or NG
OK >> Replace the transaxle assembly.
NG >> Replace TCM.

5.CHECK DTC
Perform CVT-109, "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 6.

6.CHECK TCM
1. Check TCM input/output signals. Refer to CVT-44, "TCM Input/Output Signal Reference Value". Pinout Values and Diagnostic Parameters
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the transaxle assembly.
NG >> Repair or replace damaged parts.