The Wheel Speed Sensor (WSS) generates a waveform with a frequency proportional 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 if the vehicle is or is not moving. The ECM uses this signal to control the fuel injection, ignition timing, transaxle shift scheduling and torque converter clutch scheduling. The WSS signal is also used to detect rough road conditions.
DTC DESCRIPTION
The ECM evaluates engine speed and mass air flow if there is no vehicle speed signal. This evaluation of both values will detect open circuit or short circuit errors on the wheel speed sensor. The ECM sets DTC P0501 if there is no vehicle speed signal from wheel speed sensor while both engine speed and mass air flow are higher than predetermined threshold during the predetermined time.
DTC DETECTING CONDITION
ITEM
DETECTING CONDITION
POSSIBLE CAUSE
DTC Strategy
● Check vehicle speed signal
● Open or short in harness
● Contact resistance in connectors
● Faulty wheel speed sensor
Enable Conditions
● Engine speed >2016 rpm
● Mass air flow >218mg/stk
● Coolant temperature > 60℃(140℉)
● No fuel shut-off
Threshold Value
● Vehicle speed = 0 with high engine speed and high load
Diagnostic Time
● 60 sec. (AT)/40 sec. (MT)
SCHEMATIC DIAGRAM
SIGNAL CIRCUIT INSPECTION
[With ABS]
1.
Check for open in circuit
(1)
Ignition "OFF".
(2)
Disconnect ECM and ABS or ESP Control Module connectors.
(3)
Measure resistance between terminals 22 of the ECM harness connector and 3 of the ABS Control Module harness connector(W/ABS).
Measure resistance between terminals 22 of the ECM harness connector and 6 of the ESP Control Module harness connector(W/ESP).
Specification : Approx. 0Ω
(4)
Is resistance within the specification?
▶ Go to next step as below
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
2.
Check for short to ground in circuit.
(1)
Measure resistance between terminal 22 of the ECM harness connector and chassis ground
Specification : Infinite
(2)
Is resistance within the specification?
▶ Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
[Europe & without ABS system]
3.
Check for open in circuit.
(1)
Ignition "OFF".
(2)
Disconnect ECM and wheel speed sensor(front right) harness connector.
(3)
Measure resistance between wheel speed sensor harness connector and ECM harness connector.
Specification : Approx. 0Ω
[W/O 4WD]
A.
Terminal 1(sensor) & Terminal 38(ECM)
B.
Terminal 2(sensor) & Terminal 39(ECM)
[With 4WD]
A.
Terminal 3(sensor) & Terminal 38(ECM)
B.
Terminal 4(sensor) & Terminal 39(ECM)
(4)
Is resistance within the specification?
▶ Go to next step as below.
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
4.
Check for short to ground in circuit.
(1)
Measure resistance between terminal 38 of the ECM harness connector and chassis ground.
(2)
Measure resistance between terminal 39 of the ECM harness connector and chassis ground.
Specification : Infinite
(3)
Is resistance within the specification?
▶ Check wheel speed sensor(FR) as follow:
A.
Gap between ABS sensor and trigger wheel (Air gap : 0.3~1.1 mm(0.011 ~ 0.043 in))
B.
Trigger wheel condition
C.
Sensor resistance : Approx. 1,300~1,900Ω at 20℃(68℉)
Replace wheel speed sensor as necessary and go to "Verification of Vehicle Repair" procedure.
▶ Repair as necessary 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.
Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
3.
Read "DTC Status" parameter.
4.
Is parameter displayed "History(Not Present) fault"?
▶ System performing to specification at this time. Clear the DTC.
