Circuit Description

The powertrain control module (PCM) controls the powertrain induced chassis pitch by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the controlled component. The driver has a fault line which is monitored by the PCM. When the PCM commands a component ON, the voltage of the control circuit should be low, near 0 volts. When the PCM commands the control circuit to a component OFF, the voltage potential should be a high 5 volts (4.5-5.5 volts). If the fault detection circuit senses a voltage other than what the system expects, the fault line status changes causing the DTC to set.

The PCM receives an 5 volt (4.5-5.5 volts) reference signal from the electronic suspension control (ESC) module on the powertrain induced chassis pitch circuit. The PCM grounds this circuit when the vehicle accelerates rapidly or brakes hard. When the chassis pitch input circuit goes low to about 0 volts, the ESC module commands all four shock absorber solenoids to a firm position. The PCM calculates the chassis pitch information based on the engine torque and the vehicle braking force.