Automatic Transmission

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.

CONSULT-III Reference Value in Data Monitor Mode

On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P0720 VHCL SPEED SEN-AT" with CONSULT-III or 1st judgement flicker without CONSULT-III is detected when TCM does not receive the proper voltage signal from the sensor.

Possible Cause
- Harness or connector
(The sensor circuit is open or shorted.)
- Revolution sensor

DTC Confirmation Procedure

CAUTION:
- Always drive vehicle at a safe speed.
- Be careful not to rev engine into the red zone on the tachometer.
- If performing this "DTC Confirmation Procedure" again, always turn ignition switch OFF and wait at least 10 seconds before continuing.
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. Touch "START".
3. Drive vehicle and check for an increase of "VHCL/S SE-MTR" value.
If the check result is NG, go to "Diagnosis Procedure".
If the check result is OK, go to following step.
4. Select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
5. Touch "START".
6. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VEHICLE SPEED: 30 km/h (19 MPH) or more
THROTTLE POSI: More than 1.0/8
SLCT LVR POSI: "D" position
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving conditions required for this test.
If the check result is NG, go to "Diagnosis Procedure".
If the check result is OK, go to following step.
7. Maintain the following conditions for at least 5 consecutive seconds.
ENGINE SPEED: 3,500 rpm or more
THROTTLE POSI: More than 1.0/8
SLCT LVR POSI: "D" position
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving conditions required for this test.

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

WITHOUT CONSULT-III
1. Start engine.
2. Drive vehicle under the following conditions for more than 5 seconds.
Selector lever position: "D" position
Vehicle speed: 30 km/h (19 MPH) or more
Throttle position: greater than 1.0/8 of the full throttle position
3. Perform self-diagnosis. Refer to Diagnosis Procedure Without CONSULT-III .
4. If the check result is NG, go to "Diagnosis Procedure".

Wiring Diagram - AT - VSSA/T

TCM TERMINALS AND REFERENCE VALUES
Refer to Pinout Values and Diagnostic Parameters.

Diagnosis Procedure
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Start engine.
2. Select "TCM INPUT SIGNALS" in "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
3. Read out the value of "VHCL/S SE-A/T" while driving.
Check the value changes according to driving speed.
OK or NG
OK >> GO TO 8.
NG >> GO TO 2.
2. CHECK REVOLUTION SENSOR
With CONSULT-III
1. Start engine.
2. Check power supply to revolution sensor by voltage between TCM connector terminals. Refer to Wiring Diagram and "Wiring Diagram - AT - VSSA/T".

3. If OK, check the pulse when vehicle cruises.

OK or NG
OK >> GO TO 8.
NG >> GO TO 3.
3. CHECK POWER AND SENSOR GROUND
1. Turn ignition switch OFF.
2. Disconnect the revolution sensor harness connector.
3. Turn ignition switch ON. (Do not start engine.)

4. Check voltage between revolution sensor harness connector terminals.

5. Check voltage between revolution sensor harness connector terminal and ground.

6. If OK, check harness for short to ground and short to power.
7. Reinstall any part removed.
OK or NG
OK >> GO TO 4.
NG - 1 >> Battery voltage is not supplied between terminals 1 and 3, terminals 1 and ground: GO TO 6.
NG - 2 >> Battery voltage is not supplied between terminals 1 and 3 only: GO TO 7.
4. CHECK HARNESS BETWEEN TCM AND REVOLUTION SENSOR
1. Turn ignition switch OFF.
2. Disconnect the TCM connector and revolution sensor harness connector.

3. Check continuity between TCM connector terminal and revolution sensor harness connector 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 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK TCM
1. Check TCM input/output signal. Refer to Pinout Values and Diagnostic Parameters .
2. If NG, re-check TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
6. CHECK HARNESS BETWEEN TCM AND REVOLUTION SENSOR (POWER)
1. Turn ignition switch OFF.
2. Disconnect the TCM connector and revolution sensor harness connector.

3. Check continuity between TCM connector terminals and revolution sensor harness connector terminal. Refer to 4 Speed Automatic Transmission and Wiring Diagram .

4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> 10A fuse (No.49, located in the IPDM E/R) or ignition switch are malfunctioning.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
7. CHECK HARNESS BETWEEN TCM AND REVOLUTION SENSOR (SENSOR GROUND)
1. Turn ignition switch OFF.
2. Disconnect the TCM connector and revolution sensor harness connector.

3. Check continuity between TCM connector terminal and revolution sensor harness connector terminal.