Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
Fig. 8 Vehicle Speed Sensor Location-Typical
VEHICLE SPEED AND DISTANCE SENSOR-PCM INPUT
The vehicle speed sensor is located on the speedometer pinion gear adapter (Fig. 8). The pinion gear adapter is located on the extension housing of
the transfer case (drivers side). The sensor input is used by the Powertrain Control Module (PCM) to determine vehicle speed and distance
traveled.
The speed sensor generates 8 pulses per sensor revolution. These signals, in conjunction with a closed throttle signal from the throttle position
sensor, indicate a closed throttle deceleration to the PCM. When the vehicle is stopped at idle, a closed throttle signal is received by the PCM (but
a speed sensor signal is not received).
Under deceleration conditions, the PCM adjusts the Idle Air Control (IAC) motor to maintain a desired MAP value. Under idle conditions, the
PCM adjusts the IAC motor to maintain a desired engine speed.
CIRCUIT OPERATION
Circuit K6 supplies 5 Volts from the Powertrain Control Module (PCM) to the vehicle speed sensor The K6 circuit connects to cavity B31 of the
PCM.
Circuit G7 from the vehicle speed sensor provides an input signal to the PCM. The G7 circuit connects to cavity B27 of the PCM.
The PCM provides a ground for the vehicle speed sensor signal (circuit G7) through circuit K167. Circuit K167 connects to cavity A4 of the
PCM.
