P0840

P0840 TRANSMISSION FLUID PRESSURE SEN/SW A





Description
- The 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" with CONSULT-III is detected when TCM detects an improper voltage drop when it receives the sensor signal.




Possible Cause
- 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 SEE Diagnosis Procedure.

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




Wiring Diagram - CVT - SECPS






TCM TERMINALS AND REFERENCE VALUES
CVT Trouble Diagnosis.




Diagnosis 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 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 - GO TO 5.
NG - GO TO 6.
5.CHECK DTC
With CONSULT-III
Perform "SELF-DIAG RESULTS" mode for "TRANSMISSION".
Is "P0840" detected?
YES (Only DTC P0840 detected)-Replace control valve. Service and Repair.
YES (DTC P0840 and except DTC P0840 are detected)-Replace the transaxle assembly. Removal and Installation (MR20DE), Removal and Installation (QR25DE).
NO - GO TO 6.
6.CHECK TCM
1. Check TCM input/output signals. CVT Trouble Diagnosis.
2. If NG, re-check TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK - Replace TCM. Service and Repair.
NG - Repair or replace damaged parts.