P1731

P1731 FRONT SPEED SENSOR-HIGH

Component Location






General Description

Front speed sensor is located at front of propeller shaft. This sensor receives information on wheel speed which it sends to TCCU. TCCU compares the front and rear speed sensor signals and monitors the difference in wheel rotation. This sensor signal is used to decide torque distribution amount for front and rear wheels. By rotating wheel a Hall-effect wave signal is generated.






DTC Description

This trouble code occurs if the Front Speed Sensor voltage(High) is higher than specified value.

Schematic Diagram






Signal Waveform






Terminal and Connector Inspection

1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also 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
1) Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
1) Go to " FRONT SPEED SENSOR Signal Inspection " procedure.

FRONT SPEED SENSOR Signal Inspection
1. Engine : Idling.
2. TCCU connector : Connect.
3. Monitor signal waveform between terminal B6 of TCCU harness connector B and chassis ground .
4. Select Mode s/w to AUTO Mode & Shift to L Range .
A. Specification : Signal Waveform & Data






CAUTION
The above value is only for reference. The actual value may differ from it according to various engine condition.

5. Is FRONT SPEED SENSOR display near the specified value?
YES
1) Fault is intermittent caused by poor contact in the sensor's and/or TCCU's connector or was repaired and TCCU memory was not cleared.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
1) Go to " FRONT SPEED SENSOR supply voltage inspection " procedure.

FRONT SPEED SENSOR supply voltage inspection
1. Ignition ON,
2. H-15 TRANSFER SPEED COIL connector : Disconnect.
3. Measure voltage between terminal 1 of TRANSFER SPEED COIL harness connector H-15 and chassis ground.
A. Specification : Approx. 5V






CAUTION
The above value is only for reference. The actual value may differ from it according to various engine condition.

4. Is resistance display near the specified value?
YES
1) Go to " FRONT SPEED SENSOR ground harness open circuit inspection " procedure.
NO
1) Check for front speed sensor supply harness.
2) Repair as necessary and then go to "Verification of Vehicle Repair" procedure.

FRONT SPEED SENSOR ground harness open circuit inspection
1. Ignition OFF.
2. H-15 TRANSFER SPEED COIL connector : Disconnect.
3. Measure resistance between terminal 6 of TRANSFER SPEED COIL harness connector H-15 and chassis ground.
A. Specification : Approx. 1 Ohm






CAUTION
The above value is only for reference. The actual value may differ from it according to various engine condition.

4. Is resistance display near the specified value?
YES
1) Go to " FRONT SPEED SENSOR output harness short circuit to ground inspection " procedure.
NO
1) Check for open circuit of front speed sensor ground harness.
2) Repair as necessary and then go to "Verification of Vehicle Repair" procedure.

FRONT SPEED SENSOR output harness short circuit to ground inspection
1. Ignition OFF.
2. H-15 TRANSFER SPEED COIL connector : Disconnect.
3. Measure resistance between terminal 3 of TRANSFER SPEED COIL harness connector H-15 and chassis ground.
A. Specification : Approx. Infinite Ohms






CAUTION
The above value is only for reference. The actual value may differ from it according to various engine condition.

4. Is resistance display near the specified value?
YES
1) Go to " FRONT SPEED SENSOR output harness open circuit inspection " procedure.
NO
1) Check for short to ground circuit of front speed sensor signal harness.
2) Repair as necessary and then go to "Verification of Vehicle Repair" procedure.

FRONT SPEED SENSOR output harness open circuit inspection
1. Ignition OFF.
2. H-15 TRANSFER SPEED COIL, TCCU connector : Disconnect.
3. Measure resistance between terminal 3 of TRANSFER SPEED COIL harness connector H-15 and B6 of TCCU harness connector B .
A. Specification : Approx. 0 Ohms






CAUTION
The above value is only for reference. The actual value may differ from it according to various engine condition.

4. Is resistance display near the specified value?
YES
1) Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
2) Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
1) Check for open circuit of front speed sensor signal harness.
2) Repair as necessary and then go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Using scantool, Clear DTC.
3. Operate the vehicle within DTC Enable conditions in General information.
4. Are any DTCs present ?
YES
1) Go to the applicable troubleshooting procedure.
NO
1) System is performing to specification at this time.