P1C98 – Gear Shift Position Sensor 1 Circuit Low

P1C98 Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P1C98 Possible Causes

Faulty Gear Shift Position Sensor 1,Gear Shift Position Sensor 1 harness is open or shorted,Gear Shift Position Sensor 1 circuit poor electrical connection,Faulty Transmission Control Module (TCM)

P1C98 Description

This diagnostic compares the output signal of the sensor to threshold values of normal operations. When the signal is out of range the diagnostic will be considered failing. The sensor is mounted next to the 1st – 3rd gear engagement actuator to detect a linear movement of the piston. For this purpose, a permanent magnet is mounted on the piston which is moved over a complete travel stroke. The magnet position generates a saturation area in the internal ferromagnetic core of the sensor which is transformed to an output position signal. The sensor provides an output signal with Pulse Width Modulation (PWM) at a fixed frequency and duty cycle proportional to the piston position of the actuator.