3.
Monitor the "VSS" parameters on the scantool.
The Wheel Speed Sensor (WSS) generates a waveform with a frequency according to the speed of the vehicle. The signal generated by the WSS informs the ECM not only if the vehicle speed is low or high but also is stopped the vehicle or not. The ECM uses this signal to control the fuel injection, ignition timing, transmission/transaxle shift scheduling and torque converter clutch scheduling. Also the WSS signal is used to detect rough road driving condition.
If the vehicle speed signal is below 1.0 Km/h during 2 sec under enable conditions, PCM sets P0501.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Signal check | ● Poor connection ● Open or short to ground in power circuit ● Short to ground in signal circuit ● VSS ● PCM |
Enable Conditions | ● (M/T or A/T) Engine speed during fuel cut-off 1520~3520rpm ● (only A/T at D or R position) Engine speed ＞ 3000rpm, Engine load ＞ 49.5% ● Coolant temperature＞ -7℃ | |
Threshold Value | ● Vehicle speed signal 〈 1.0 Km/h | |
Diagnostic Time | ● 2 sec | |
MIL | ● ON |
Connect scantool to Data Link Connector(DLC).
Warm up the engine to normal operating temperature.
Monitor the "VSS" parameters on the scantool.
Are the parameters displayed correctly?
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or wasrepaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poorconnection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.
▶ Go to "W/Harness Inspection " procedure.
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.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
▶ Repair as necessary and go to "Verification of vehicle Repair" procedure.
▶ Go to "Power Circuit Inspection" procedure.
Key "ON" ＆ ENG "OFF".
Measure voltage between terminal 2 of the Vehicle speed sensor harness connector and chassis ground. (Connect wheel speed sensor connector)
Specification : Approx. B+
Is the measured voltage within specification?
▶ Go to "Signal Circuit Inspection" procedure.
▶ Repair open or short to ground in harness, and go to "Verification of Vehicle Repair" procedure.
Check short to ground in harness.
Key "OFF".
Disconnect PCM connector.
Disconnect wheel speed sensor connector.
Measure resistance between terminal 3 of the vehicle speed sensor harness connector and chassis ground.
Specification : Infinite
Is the measured resistance within specification?
▶ Go to "Check open in harness" as follows.
▶ Repair short to ground in harness, and go to "Verification of Vehicle Repair" procedure.
Check for open in harness.
Key "OFF".
Disconnect PCM connector.
Disconnect wheel speed sensor connector.
Measure resistance between terminal 59 of PCM/ECM harness connector and terminal 3 harness cnnector.
Specification : Approx. below 1Ω
Is the measured resistance within specifications?
▶ Go to "Ground inspection" procedure.
▶ Repair Open circuit and then, go to "Verification of Vehicle Repair" procedure.
Key "OFF".
Disconnect VSS connector.
Key "ON" ＆ ENG "OFF".
Measure the voltage between terminal 3 of VSS harness connector and chassis ground.(A)
Measure the voltage between terminal 3 and 1 of VSS harness connector.(B)
Specification : "A" - "B" = Below 200mV
Is the measured voltage within specification?
▶ Go to "Component Inspection" procedure.
▶ Repair Open in signal circuit and then, go to "Verification of Vehicle Repair" procedure.
ENG "ON".
Measure signal waveform of wheel speed sensor while driving.
Is the signal waveform normal?
▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known - good ABS or ESP control unit and check for proper operation. If the problem is corrected, replace ABS or ESP control unit and go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System is performing to specification at this time.
