XC90 FWD L6-3.2L VIN 98 B6324S (2007)
The function of the accelerator pedal position sensor is to provide the engine control module (ECM) and central electronic module (CEM) information
on the position of the accelerator pedal. The engine control module (ECM) uses this data to deploy the shutter in the throttle unit to the correct angle.
The accelerator pedal position sensor consists of a plastic housing with two potentiometers, and an Analog/Digital converter. The potentiometers are
connected to a common shaft which is affected by the position of the accelerator pedal.
The accelerator pedal (AP) position sensor transmits an analog and a pulse width modulated (PWM-signal to the engine control module (ECM). These
signals indicate the position of the accelerator pedal (AP). The digital signal is generated by the sensors Analog/Digital converter.
The analog and digital signals are used at the same time by the engine control module (ECM) to regulate the throttle shutter angle.
The power supply to the two potentiometers is different. The analog potentiometer is supplied with 5 V via the engine control module (ECM). The
digital potentiometer is supplied with 12 V via the system relay and is grounded in the car body.
The digital signal is used together with the analog signal for diagnostics of the accelerator pedal position sensor.
Accelerator pedal (AP) position sensor's signals can be read off.
A diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects a difference between the analog and digital signals. The engine
control module (ECM) then uses a minimal value to ensure the function (limp home).
The accelerator pedal (AP) position sensor is located on the accelerator pedal bracket.
Part 2
Design (Continued)
Outside temperature sensor
The outside temperature sensor detects the temperature in the surrounding air. The signal is used by the engine control module (ECM) as a substitute
value in the event of a fault in certain components or functions and to control certain diagnostic functions.
The sensor is a negative temperature coefficient (NTC) type which is supplied with power from the control module (signal). The resistance in the sensor
changes with the outside temperature. This alters the signal to the engine control module (ECM). The lower the temperature the higher the voltage (high
resistance). A high temperature results in low voltage (low resistance).
The outside temperature sensor is positioned in the left door mirror.
The outside temperature sensor can be diagnosed by the engine control module (ECM) and the sensor value can be read off.
Engine coolant level sensor