1F–242 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F280
DIAGNOSTIC TROUBLE CODE (DTC) – P0501 VEHICLE SPEED NO SIGNAL
(M/T ONLY)
Circuit Description
Vehicle speed information is provided to the engine con-
trol 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 ve-
hicle speed is over 3 mph (5km/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 Diagnostic Trouble Code (DTC) will de-
tect if vehicle speed is reasonable according to engine
rpm and load.
Conditions for Setting the DTC
D Vehicle speed is not change at least 10 seconds.
D Engine speed is greater than 2,100rpm.
D MAF is greater than 152mg/tdc.
Action taken when The DTCs Sets
D The Malfunction Indicator Lamp (MIL) will illuminate.
D 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.
D A history DTC is stored.
Conditions for Clearing the MIL/DTC
D The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
D A history DTC will clear after 40 consecutive warm up
cycles without a fault.
D Using the scan tool can clear DTC(s).
Diagnostic Aids
An Intermittent problem may be caused by a poor con-
nection, rubbed through wire insulation, or wire that is
broken inside the insulation.
VSS signal circuit should be thoroughly checked for the
following conditions
D Backed-out terminals
D Improper mating
D Broken locks
D Improperly formed
D Damaged terminals
D Poor terminals to wire connection
D Physical damage to the wiring harness
Ensure the VSS is correctly torqued to the trnasaxle
housing.
Refer to “intermittents” in this Section.
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