P0501
DTC P0501 Vehicle Speed Sensor Unplausible SignalWiring Diagram:
Circuit Description
Vehicle speed information is provided to the engine control module (ECM) by the voltage speed sensor (VSS) is a permanent magnet generator that is mounted in the transaxle and produces a pulsing voltage whenever vehicle speed is over 3 mph (5 km/h). The A/C voltage level and the number of pulses increase with vehicle speed. The ECM converts the pulsing voltage into mph (km/h) and than supplies the necessary signal to the instrument panel for speedometer/odometer operation and to the cruise control module and multi-function alarm module operation. The DTC will detect if vehicle speed is reasonable according to engine rpm and load.
Conditions for Setting the DTC
- Vehicle speed is not change at least 25 seconds.
- Engine speed is greater than 2,500 rpm.
- MAF is greater than 180 mg/stk.
Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.
- Coolant fan turns on.
Conditions for Clearing the MIL/DTC
- The MIL will turn off at the end 3 consecutive ignition cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
An Intermittent problem may be caused by a poor connection, rubbed through wire insulation, or wire that is broken inside the insulation.
VSS signal circuit should be thoroughly checked for the following conditions
- Backed-out terminals
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminal to wire connection
- Physical damage to the wiring harness
Ensure the VSS is correctly torqued to the transaxle housing.
Refer to Intermittents. Intermittents
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Step 10 - 13:
DTC P0501 - Vehicle Speed Sensor Unplausible Signal