P0720

DTC P0720 OUTPUT SPEED SENSOR CIRCUIT





COMPONENT LOCATION

GENERAL DESCRIPTION
The Output Speed Sensor outputs pulse-signals according to the revolutions of the output shaft of the transmission. The Output Speed Sensor is installed in front of the Transfer Drive Gear to determine the Transfer Drive Gear rpms by counting the frequency of the pulses. This value, together with the throttle position data, is mainly used to decide the optimum gear position.

DTC DESCRIPTION
The TCM sets this code if the calculated value of the pulse-signal is noticeably different from the value calculated, using the Vehicle Speed Sensor output, when the vehicle is running faster than 30 km/h. The TCM will initiate the fail safe function if this code is detected.





DTC DETECTING CONDITION

SPECIFICATION
Refer to DTC P0715. P0715

SIGNAL WAVEFORM
Refer to DTC P0715. P0715

MONITOR SCANTOOL DATA
1. Connect scantool to data link connector (DLC).
2. Engine "ON".
3. Monitor the "OUTPUT SPEED SENSOR" parameter on the scantool.





4. Driving at speed of over 19 Mile/h (30 Km/h).
Specification: Increasing Gradually
5. Does "Output speed sensor" follow the reference data?
YES >>
^ Fault is intermittent caused by poor contact in the sensor's and/or TCM (PCM)'s connector or was repaired and TCM (PCM) memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration or damage. Repair or replace as necessary and go to "Verification Vehicle Repair" procedure.
NO >>
^ Go to "Terminal & Connector inspection" procedure.

TERMINAL & CONNECTOR INSPECTION
1. Many malfunctions in the electrical system may be caused from poor harness and terminals. These faults can be caused by interference from other electrical systems and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES >>
^ Repair as necessary and go to "Verification vehicle Repair" procedure.
NO >>
^ Go to "Signal circuit inspection" procedure.

SIGNAL CIRCUIT INSPECTION
1. Ignition "ON" & Engine "OFF".
2. Disconnect the "OUTPUT SPEED SENSOR" connector.





3. Measure voltage between terminal "2" of the OUTPUT SPEED SENSOR harness connector and chassis ground.
Specification: approximately 5V
4. Is voltage within specification?
YES >>
^ Go to "Power Supply circuit Inspection" procedure.
NO >>
^ Check for open or short in harness. Repair as necessary and Go to "Verification Vehicle Repair" procedure
^ If signal circuit in harness is OK, Go to "Check PCM/TCM" of the "Component Inspection" procedure.

POWER SUPPLY CIRCUIT INSPECTION
1. Ignition "ON" & Engine "OFF".
2. Disconnect the "OUTPUT SPEED SENSOR" connector.





3. Measure voltage between terminal "3" of the OUTPUT SPEED SENSOR harness connector and chassis ground.
Specification: approximately B+
4. Is voltage within specification?
YES >>
^ Go to "Ground circuit inspection" procedure.
NO >>
^ Check for open in harness. Repair as necessary and Go to "Verification Vehicle Repair" procedure.

GROUND CIRCUIT INSPECTION
1. Ignition "ON" & Engine "OFF".
2. Disconnect the "OUTPUT SPEED SENSOR" connector.





3. Measure resistance between terminal "1" of the OUTPUT SPEED SENSOR harness connector and chassis ground.
Specification: approximately 0 ohms
4. Is resistance within specification?
YES >>
^ Go to "Component Inspection" procedure.
NO >>
^ Check for open in harness. Repair as necessary and Go to "Verification Vehicle Repair" procedure.
^ If ground circuit in harness is OK, Go to "Check PCM/TCM" of the "Component Inspection" procedure.

COMPONENT INSPECTION
1. Check "OUTPUT SPEED SENSOR"
1. Ignition "OFF".
2. Disconnect the "OUTPUT SPEED SENSOR" connector.





3. Measure resistance between terminal "1", "2" and "2", "3" and "1", "3" of the "OUTPUT SPEED SENSOR connector.
Specification: Refer to "Reference data"
4. Is resistance within specifications?





[REFERENCE DATA]

YES >>
^ Go to "CHECK PCM/TCM" as below.
NO >>
^ Replace "OUTPUT SPEED SENSOR" as necessary and Go to "Verification Vehicle Repair" procedure.
2. CHECK PCM/TCM
1. Ignition "ON" & Engine "OFF".
2. Connect "OUTPUT SPEED SENSOR" connector.
3. Install scantool and select a SIMU-SCAN.





4. Simulate frequency to OUTPUT SPEED SENSOR signal circuit.
5. Is "OUTPUT SPEED SENSOR" signal value changed according to simulation frequency?
YES >>
^ Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO >>
^ Substitute with a known-good PCM/TCM and check for proper operation. If the problem is corrected, replace PCM/TCM as necessary and then go to "Verification of Vehicle Repair" procedure.

VERIFICATION OF VEHICLE REPAIR
Refer to DTC P0560. P0560