6E–455
6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
PCM Input/Outputs
Inputs – Operating Conditions Read
D
Air Conditioning “ON” or “OFF”
D
Engine Coolant Temperature
D
Crankshaft Position
D
Exhaust Oxygen Content
D
Electronic Ignition
D
Manifold Absolute Pressure
D
Battery Voltage
D
Throttle Position
D
Vehicle Speed
D
Fuel Pump Voltage
D
Power Steering Pressure
D
Intake Air Temperature
D
Mass Air Flow
D
Engine Knock
Outputs – Systems Controlled
D
EVAP Canister Purge
D
Exhaust Gas Recirculation (EGR)
D
Ignition Control
D
Fuel Control
D
ION Sensing Module
D
Electric Fuel Pump
D
Air Conditioning
D
Diagnostics
– Malfunction Indicator Lamp
– Data Link Connector (DLC)
– Data Output
D
Transmission Control Module
PCM Service Precautions
The PCM is designed to withstand normal current draws
associated with vehicle operation. Avoid overloading any
circuit. When testing for opens and shorts, do not ground
or apply voltage to any of the PCM’s circuits unless
instructed to do so. These circuits should only be tested
using digital voltmeter J 39200. The PCM should remain
connected to the PCM or to a recommended breakout
box.
Reprogramming The PCM
Reprogramming of the PCM is done without removing it
from the vehicle . This provides a flexible and
cost-effective method of making changes in software
calibrations.
Refer to the latest Techline information on
reprogramming or flashing procedures.
Throttle Position (TP) Sensor
The throttle position (TP) sensor is a potentiometer
connected to the throttle shaft on the throttle body. The
PCM monitors the voltage on the signal line and
calculates throttle position. As the throttle valve angle is
changed (accelerator pedal moved), the TP sensor signal
also changes. At a closed throttle position, the output of
the TP1 sensor is low. As the throttle valve opens, the
output increases so that at wide open throttle (WOT), the
output voltage should be above 92% (Tech 2 Display).
The PCM calculates fuel delivery based on throttle valve
angle (driver demand). A broken or loose TP sensor may
cause intermittent bursts of fuel from an injector and
unstable idle because the PCM thinks the throttle is
moving.
060RY00027
Transmission Fluid Temperature (TFT)
Sensor
The transmission fluid temperature sensor is a thermistor
which changes its resistance based on the temperature of
the transmission fluid. For a complete description of the
TFT sensor, refer to
4L30-E Automatic Transmission
Diagnosis section.
A failure in the TFT sensor or associated wiring will cause
DTC P0712 or DTC P0713 to set. In this case, engine
coolant temperature will be substituted for the TFT
sensor value and the transmission will operate normally.
Transmission Range Switch
IMPORTANT:
The vehicle should not be driven with the
transmission range switch disconnected; idle quality will
be affected.
The four inputs from the transmission range switch
indicate to the PCM which position is selected by the
transmission selector lever. This information is used for
ignition timing, EVAP canister purge, EGR operation.
For more information on the transmission on the
transmission range switch, refer to
4L30-E Automatic
Transmission section.
Vehicle Speed Sensor (VSS)
The PCM determines the speed of the vehicle by
converting a pulsing voltage signal from the vehicle speed
sensor (VSS) into miles per hour. The PCM uses this
signal to operate the cruise control, speedometer, and the
TCC and shift solenoids in the transmission. For more
information on the TCC and shift solenoids, refer to
4L30-E Automatic Transmission section.
SECTION