P0720

DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)

Description
The revolution sensor detects the revolution of the idler gear parking pawl lock gear and emits a pulse signal. The pulse signal is sent to the TCM which converts it into vehicle speed.

On Board Diagnosis Logic
^ This is an OBD-II self-diagnostic item.
^ Diagnostic trouble code "VEH SPD SEN/CIR AT" with CONSULT-II or P0720 without CONSULT-II is detected under the following conditions.
- When TCM does not receive the proper voltage signal from the sensor.
- After ignition switch is turned "ON", irregular signal input from vehicle speed sensor MTR before the vehicle starts moving.

Possible Cause
^ Harness or connectors (The sensor circuit is open or shorted.)
^ Revolution sensor
^ Vehicle speed sensor MTR

DTC Confirmation Procedure

CAUTION:
^ Always drive vehicle at a safe speed.
^ Be careful not to rev engine into the red zone on the tachometer.

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting 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" position. (Do not start engine.)
2. Select "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Check for an increase of "VHCL/S SE A/T" value in response to "VHCL/S SE MTR" value.
If the check result is NG, go to "Diagnostic Procedure". If the check result is OK, go to following step.
4. Select "DATA MONITOR" mode for "ENGINE" with CONSULT-II.
5. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL SPEED SE: 30 km/h (19 MPH) or more
THRTL POS SEN: More than 1.0/8
Selector lever: "D" position
If the check result is NG, go to "Diagnostic Procedure".
If the check result is OK, go to following step.
6. Maintain the following conditions for at least 5 consecutive seconds.
ENGINE SPEED: 3,500 rpm or more
THRTL POS SEN: More than 1.0/8
Selector lever: "D" position If the check result is NG, go to "Diagnostic Procedure".

WITH GST
Follow the procedure "With CONSULT-II".

AT-VSSAT-01:

Wiring Diagram-AT-VSSA/T

Diagnostic Procedure
1. CHECK INPUT SIGNALS

With CONSULT-II
1. Turn ignition switch to "ON" position. (Do not start engine.)





2. Select "TCM INPUT SIGNALS" in "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Start the engine.
4. Read out the value of "VHCL/S SE A/T" while driving. Check the value changes according to driving speed.

With GST
Follow the procedure "With CONSULT-II".

OK or NG
OK >> GO TO 5.
NG >> GO TO 3.

2. CHECK REVOLUTION SENSOR (WITH CONSULT-II)

With CONSULT-II
1. Start the engine.





2. Check the pulse when vehicle cruises.





OK or NG
OK >> GO TO 6.
NG >> GO TO 3.

3. CHECK HARNESS BETWEEN TCM AND A/T UNIT ASSEMBLY HARNESS CONNECTOR
1. Turn ignition switch to "OFF" position.
2. Disconnect TCM connector.








3. Check continuity between A/T unit assembly harness connector and TCM connector.
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 TERMINAL CORD ASSEMBLY
1. Remove oil pan.
2. Disconnect A/T unit assembly harness connector and control valve assembly harness connector.








3. Check continuity between A/T unit assembly harness connector and control valve assembly harness connector.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.

OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.

5. DETECT MALFUNCTION ITEMS
1. Check control valve assembly.
2. Disassemble A/T.
3. Check revolution sensor.

OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.

6. CHECK DTC
Perform "DTC Confirmation Procedure".

OK or NG
OK >> INSPECTION END
NG >> GO TO 7.

7. PERFORM TCM INSPECTION
1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.

OK or NG
OK >> INSPECTION END
NG >> Repair or replace damaged parts.