P0721
DTC P0721 OUTPUT SPEED SENSOR CIRCUIT RANGE/PERFORMANCECOMPONENT 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 (PCM) 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 (PCM) will initiate the fail safe function if this code is detected.
DTC DETECTING CONDITION
DTC DETECTING CONDITION:
SPECIFICATION
Input shaft & Output shaft speed sensor
- 40 Type: Hall sensor
- Current consumption: 22 mA (MAX) 40
- Sensor body and sensor connector have been unified as one.
SCHEMATIC DIAGRAM
SCHEMATIC DIAGRAM:
SIGNAL WAVEFORM
SIGNAL WAVEFORM:
MONITOR SCAN TOOL DATA
1. Connect SCAN TOOL to data link connector (DLC).
2. Engine ON.
3. Monitor the OUTPUT SPEED SENSOR parameter on the SCAN TOOL.
4. Driving at speed of over 30 km/h (19 mph).
Specification: Increasing Gradually
Specification:
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 of 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 of 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 5 V
Specification:
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 of Vehicle Repair procedure. If signal circuit in harness is OK, Go to Check TCM (PCM) 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+
Specification:
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 of 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
Specification:
4. Is resistance within specification?
YES > Go to Component Inspection procedure.
NO > Check for open in harness. Repair as necessary and Go to Verification of Vehicle Repair procedure. If ground circuit in harness is OK, Go to Check TCM (PCM) 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
Specification:
4. Is resistance within specifications?
[REFERENCE DATA]
REFERENCE DATA:
YES > Go to CHECK TCM (PCM).
NO > Replace OUTPUT SPEED SENSOR as necessary and Go to Verification of Vehicle Repair procedure.
2. CHECK TCM (PCM)
1. Ignition ON & Engine OFF.
2. Connect OUTPUT SPEED SENSOR connector.
3. Install SCAN TOOL 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 TCM (PCM) and check for proper operation. If the problem is corrected, replace TCM (PCM) as necessary and then go to Verification of Vehicle Repair procedure.
VERIFICATION OF VEHICLE REPAIR
Refer to DTC P0717. P0717