Diagnostic Trouble Code (DTC) P0501

Vehicle Speed No Signal (M/T Only)

Circuit Features

  • The Voltage Speed Sensor (VSS) is a permanent magnet generator.
  • It is located on the transaxle and is capable of generating a pulsing voltage every time the vehicle speed is beyond 3 mph (5km/h).
  • The VSS supplies vehicle speed information to the ECM.
  • Increasing vehicle speed automatically raises the A/C voltage level and the number of pulses.
  • After transforming the pulsing voltage into mph (km/h) the ECM  supplies the requisite signal to the instrument panel for speedometer/ odometer operation.
  • Then it gives signal to the cruise control module and multi-function alarm module operation.
  • The Diagnostic Trouble Code (DTC) is so devised that it can identify and automatically set  if vehicle speed is reasonable according to engine rpm and load.

 

 

 

 

 

 

 

 

 

Pre-requisites  for setting the DTC

Task boosted after DTC sets

When will DTC clear?

1) When vehicle speed does not change for at least 25 seconds

 

 

1) The Malfunction Indicator Lamp (MIL) will be seen glowing.

 

1) The MIL will go off after four repetitive ignition cycles where the diagnostic runs flawlessly.

 

2) When engine speed is beyond 2,500rpm.

 

2) The ECM will begin to record operating conditions at the time when the diagnostic fails which will be stored in the Freeze Frame.

 

2) A history DTC will clear by itself after 40 successive warm-up cycles flawlessly

3) When MAF is > 180mg/tdc

3) A history Diagnostic Trouble Code (DTC) will be stored.

 

 

3) The scan tool can be used to remove all existing DTCs.

 

-

4)  The coolant fan turns on.

 

4) Disconnecting the ECM battery feed for 10 seconds

 

 

 

 

 

 

 

Diagnostic Assistance

A resultant intermittent problem may be generated by a) an ill                                           connection, b) rubbed through wire insulation, or c) wire that is tampered inside the insulation.

Check VSS signal circuit thoroughly for the following conditions

  • Broken locks
  • Improper mating
  • Backed-out terminals
  • Improperly formed
  • Damaged terminals
  • Poor terminal to wire connection
  • Physical damage to the wiring harness

The VSS is should be properly torqued to the transaxle housing.

You also need to refer to "Intermit tents" in this section.