P0501
P0501Component Location:
General Description
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
Checking vehicle speed signal from wheel speed sensor or ABS/ESC control every 30 sec. under detecting condition, if signal is out of specifications for more than 20 sec., PCM sets P0501. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC Detecting Condition:
Signal Waveform:
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 parameter displayed "Present fault"?
YES
a. Go to "Terminal and Connector inspection" procedure.
NO
a. Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM 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
a. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
a. Go to "Signal Circuit Inspection" procedure.
Signal Circuit Inspection
CAUTION: 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".
1. Check short to ground in harness
1. IG "OFF"
2. Disconnect PCM connector and ABS or ESC control module connector.
3. Measure resistance between terminal 52 of PCM harness connector 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 PCM connector and ABS or ESC control module connector.
3. Measure resistance between terminal "52" of PCM harness connector and terminal "3(6)" of ABS(ESC) control module harness connector.
Specification : Approx below 1 ohm
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 (Refer to "C1203 Wheel speed sensor front-RH open/short")
3. Is the wheel speed sensor normal?
YES
- Substitute with a known - good PCM/ABS or ESC control unit and check for proper operation.
If the problem is corrected, replace PCM/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.
CAUTION: There is a memory reset function on scantool that can erase optional components automatically detected and memorized by PCM. Before or after testing PCM on the vehicle, use this function to reuse the PCM.
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 parameter displayed "History(Not Present) fault"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.