
Electronic Engine Controls
WARNING
To avoid personal injury and/or vehicle damage, refer to the service precautions at the
beginning of this section.
General Information
The Engine Management System (EMS) uses several different sensors and actuators to
gather and control various emissions and driveability aspects of the vehicle. These may
include but are not limited to:
MAP
– Manifold Absolute Pressure Sensor
FTP
– Fuel Tank Pressure Sensor
ECT
– Engine Coolant Temperature Sensor
A/F
– Air Fuel Ratio Sensor
APP
– Accelerator Pedal Position Sensor
CKP
– Crankshaft Position Sensor
CMP
– Camshaft Position Sensor
HO
2
S
– Heated Oxygen Sensor
IAT
– Intake Air Temperature Sensor
KS
– Knock Sensor
MAF
– Mass Air Flow Sensor
TP
– Throttle Position Sensor
VSS
– Vehicle Speed Sensor
These sensors provide critical information to the EMS such as, barometric pressure,
atmospheric pressure, intake manifold/engine vacuum, fuel tank pressures and changes
as the vehicle is operated.
MAP Sensor
The EMS uses the MAP sensor on systems that have a Mass Airflow Sensor (MAF) as a
backup. The EMS also uses the MAP sensor as an EGR diagnostic device and as an
engine load verification device. The EMS system uses this information to calculate engine
load and EGR flow rates. The EMS uses speed-density calculations (non-mass airflow
sensor systems) to determine the required amount of fuel delivery.
FTP Sensor
The Fuel Tank Pressure (FTP) sensor is part of the evaporative emissions system. The
engine control system monitors gasoline vapor pressures in the fuel tank to determine fuel
tank sealing. The FTP sensor can be used in conjunction with an EVAP vent valve and an
EVAP canister purge valve.
Canister Purge Valve Only Vehicles
When ambient temperatures are above 68° Fahrenheit the gasoline in the fuel tank
vaporizes increasing fuel tank pressure. The FTP sensor is used to determine how much
Содержание TrailBlazer
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Страница 26: ...Fig 3 Typical body and undervehicle maintenance locations Refer to chart for descriptions ...
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Страница 59: ...Cylinder head bolt removal and installation 32 Remove and discard the bolts from the cylinder head ...
Страница 175: ...Spring free length check Valve spring squareness check ...
Страница 192: ...Front of piston mark ...
Страница 361: ...5 3L Engine Except Saab Underhood Fuse Block 2003 2005 Early Production ...
Страница 469: ...Removing the outer band from the CV boot Removing the inner band from the CV boot ...
Страница 470: ...Removing the CV boot from the joint housing Clean the CV joint housing prior to removing boot ...
Страница 471: ...Removing the CV joint housing assembly Removing the CV joint ...
Страница 472: ...Inspecting the CV joint housing Removing the CV joint outer snap ring ...
Страница 473: ...Checking the CV joint snap ring for wear CV joint snap ring typical ...
Страница 474: ...Removing the CV joint assembly Removing the CV joint inner snap ring ...
Страница 475: ...Installing the CV joint assembly typical ...
Страница 506: ...Tie Rod End Removal Installation Inner Tie Rod End To Remove Inner tie rod assembly Magnasteer ...
Страница 553: ...9 Torque the lug nuts to specification 10 Lower the vehicle ...
Страница 556: ...Toe in Frame Misalignment Frame misalignment ...
Страница 588: ...Bleeding caliper ...
Страница 596: ...Inboard brake pad removal and installation 10 Remove the inboard brake pad from the brake caliper ...
Страница 624: ...Manifold gauge set components Refrigerant recovery recycling station ...
Страница 662: ...Lower instrument panel retaining volts 25 Remove the lower retaining bolts from the instrument panel I P ...
Страница 676: ...A C Specifications ...
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