P0501

DTC P0501






GENERAL DESCRIPTION
A Wheel Speed Sensor(RF) is used by the ECM/PCM to calculate vehicle speed. This sensor is connected directly to the ECM/PCM in non-ABS vehicles. On ABS vehicles, the sensor feeds the ABS control module first; the signal is then sent to the ECM/PCM.

DTC DESCRIPTION
If the vehicle speed signal is below 0.62 MPH during 2 sec under enable conditions, ECM/PCM sets P0501.

DTC Detecting Condition:

Schematic Diagram - A/T:

Schematic Diagram - M/T:

Signal Waveform And Data:

MONITOR SCANTOOL DATA
ABS Vehicle
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
3. Monitor the "VSS" parameters on the scantool.(ENG. Control)




4. Monitor the "WHEEL SPEED SENSOR-FR" parameter on the Scantool. (ABS Control)
5. Are the parameters displayed correctly?

YES - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM/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 - Check the DTCs on ABS(ESP) Module first. If there are DTCs on ABS(ESP) Module, Refer to the Trouble Shooting Guide for ABS(ESP). But, if there isn't DTC on ABS(ESP) Module, go to "Terminal& Connector Inspection" procedure.

TERMINAL AND CONNECTOR INSPECTION
ABS Vehicle
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 - Repair as necessary and go to "Verification of vehicle Repair" procedure.

NO - Go to "Signal Circuit Inspection" procedure.

SIGNAL CIRCUIT INSPECTION
1. Check short to ground in harness.
a. Key "OFF".
b. Disconnect ECM/PCM connector.
c. Disconnect ABS control unit.







d. Measure resistance between terminal 20/C01-1 of ECM/PCM harness connector and chassis ground.Measure resistance between terminal 64/C01 of ECM/PCM harness connector and chassis ground

Specification : Infinite

e. Is the measured resistance within specification?

YES - Go to "Check open in harness" as follows.

NO - Repair short to ground in harness, and go to "Verification of Vehicle Repair" procedure.

2. Check for open in harness.
a. Key "OFF".
b. Disconnect ECM/PCM connector.
c. Disconnect ABS control unit connector.







d. Measure resistance between terminal 20/C01-1 of ECM/PCM harness connector and terminal 3/E51of ABS control module harness connector.(A/T)Measure resistance between terminal 64/C01 of ECM/PCM harness connector and terminal 3/E51of ABS control module harness connector.(M/T)

Specification : Approx. below 1 ohm

e. Is the measured resistance within specifications?

YES - Go to "Component inspection" procedure.

NO - Repair Open circuit and then, go to "Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION
ABS Vehicle
1. ENG "ON".

Specification:

2. Measure signal waveform of Vehicle Speed from ABS to ECM/PCM while driving.
3. Is the signal waveform normal?

YES - Substitute with a known - good ECM/PCM and check for proper operation. If the problem is corrected, replace ECM/PCM and go to "Verification of Vehicle Repair" procedure.

NO - Substitute with a known - good ABS control unit and check for proper operation. If the problem is corrected, replace ABS control unit and go to "Verification of Vehicle Repair" procedure.

MONITOR SCANTOOL DATA
NON-ABS VEHICLE
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.




3. Monitor the "VSS" parameters on the scantool.
4. Are the parameters displayed correctly?

YES - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM/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 "W/Harness Inspection " procedure.

TERMINAL AND CONNECTOR INSPECTION

NON-ABS VEHICLE
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 - Repair as necessary and go to "Verification of vehicle Repair" procedure.

NO - Go to "Power Circuit Inspection" procedure.

POWER SUPPLY CIRCUIT INSPECTION
1. Key "ON".




2. Measure voltage between terminal 1/E50 of the wheel speed sensor harness connector and chassis ground. (Connect wheel speed sensor connector)

Specification : Approx. B+

3. Is the measured voltage within specification?

YES - Go to "Signal Circuit Inspection" procedure.

NO - Repair open or short to ground in harness, and go to "Verification of Vehicle Repair" procedure.

SIGNAL CIRCUIT INSPECTION
1. Key "ON".




2. Measure the voltage between terminal 2/E50 of wheel speed sensor harness connector and chassis ground. (Don't disconnect the WSS connector.)

Specification : 0.7 V or 1.4 V

3. Is the measured voltage within specifications?

YES - Go to "Component Inspection" as follows.

NO - Repair Open or Short in harness, and go to "Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION
NON-ABS VEHICLE
1. Engine "ON".

Specification:

2. Measure signal waveform of wheel speed sensor while driving.
3. Is the signal waveform normal?

YES - Substitute with a known - good ECM/PCM and check for proper operation. If the problem is corrected, replace ECM/PCM and go to "Verification of Vehicle Repair" procedure.

NO - Substitute with a known - good wheel speed sensor and check for proper operation. If the problem is corrected, replace wheel speed sensor and 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. Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
3. Are any DTCs present ?

YES - Go to the applicable troubleshooting procedure.

NO - System is performing to specification at this time.