P0501
P0501Component Location:
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 PCM not only if the vehicle speed is low or high but also if the vehicle is or is not moving. The PCM 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., PCM sets P0501. MIL (Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC Detecting Condition:
Schematic Diagram:
Signal Waveform:
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 - Go to "Terminal and Connector inspection" procedure.
NO - Fault is intermittent caused by poor contact in the sensors 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 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
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".
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 "12" of ABS or 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.
NOTE: There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. After testing PCM on the vehicle, use this function to reuse the PCM on the others
Verification of Vehicle Repair
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.