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Vehicle Speed Output From the TCM|Page 2519 > < Vehicle Speed Output From the TCM
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Vehicle Speed Sensor: Description and Operation
Vehicle Speed Sensor Operation

NOTE:  Applies only to vehicles without 4speed/overdrive (41TE) transmission.

LOCATION

 

Sensor mounted in transaxle extension housing.

 
PURPOSE

 

The Powertrain Control Module (PCM) uses sensor input, when it receives a "closed throttle" input from the Throttle Position Sensor (TPS), to
determine whether vehicle is decelerating or stopped. 

 

The PCM stores sensor input as distance traveled.

 

The PCM uses sensor input to control speedometer.

 
OPERATION

 

During idle, (no signals being received from sensor), the PCM  actuates the Idle Air Control (IAC) motor to maintain desired engine idle speed. 

 

During closed throttle deceleration, (slower signals received from sensor), the PCM actuates the IAC motor to maintain desired Manifold Absolute
Pressure (MAP) sensor value.

 

Sensor generates 8 voltage pulses per axle shaft revolution.

Vehicle Speed Output From the TCM|Page 2519 > < Vehicle Speed Output From the TCM