P0501
GENERAL DESCRIPTION
The Vehicle Speed Sensor(VSS) or Wheel Speed Sensor (WSS) generates a waveform with a frequency proportional to the speed of the vehicle. The signal generated by the VSS or 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 VSS or WSS signal is also used to detect rough road conditions.
DTC DESCRIPTION
Checking vehicle speed signal every from wheel speed sensor or ABS(or ESC) control every 30 sec. under detecting condition, if an signal is in the detecting condition for more than 20 sec., ECM sets P0501. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC DETECTING CONDITION
SIGNAL WAVEFORM AND DATA
SCHEMATIC DIAGRAM
MONITOR DTC STATUS
1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F5(INFO) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.
(5) Is "Present" Fault displayed?
YES
> Go to "Terminal and connector inspection" procedure.
NO
> Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminal condition. 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
NOTE:
This procedure is applied to vehicle with ABS (or ESC)
In case of no ABS(or ESC), refer to "C1203 Wheel speed sensor front-RH open/short". C1203
1. Check short to ground in harness
(1) IG "OFF"
(2) Disconnect ECM connector and ABS or ESC control module connector.
(3) Measure resistance between terminal 52 of ECM harness connector(C144-A) and chassis ground.
Specification : Infinite
(4) Is the measured resistance within specifications?
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
(1) Ignition "OFF"
(2) Disconnect ECM connector and ABS or ESC control module connector.
(3) Measure resistance between terminal "52" of ECM harness connector (C144-A) and terminal "21" of ESC control module harness connector.
Specification : Approx. below 1Ohms
NOTE:
(4) Is the measured resistance within specifications?
YES
> Go to " Check wheel speed sensor " procedure.
NO
> Check open in harness.
> Repair or replace as necessary and then, go to " Verification of Vehicle Repair" procedure.
3. Check wheel speed sensor
(1) IG "OFF"
(2) Check open or short in wheel speed sensor
(3) Is the wheel speed sensor normal?
YES
> Substitute with a known - good ECM/ ESC control unit and check for proper operation.
If the problem is corrected, replace ECM/ ABS or ESC control unit and go to "Verification of Vehicle Repair" procedure
NO
> Repair or replace it as necessary.
> And then go to " Verification of Vehicle Repair" procedure.
NOTE:
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by ECM. After testing ECM on the vehicle, use this function before reusing the ECM
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 F5(INFO) 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 "History (Not Present)" fault displayed?
YES
> System performing to specification at this time. Clear the DTC
NO
> Go to the applicable troubleshooting procedure.