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Engine Controls - 4.4l - Introduction (1 of 2) Cadillac XLR I

Diagnostic Starting Point - Engine Controls

Begin the system diagnosis with Diagnostic System Check - Vehicle . The Diagnostic System Check - Vehicle will provide the following information

  1. The identification of the control modules which command the system
  2. The ability of the control modules to communicate through the serial data circuit
  3. The identification of any stored diagnostic trouble codes (DTCs) and the codes' statuses

The use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.

Scan Tool Data List

The Engine Scan Tool Data List contains all engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A parameter may appear in any one of the data lists, and in some cases may appear more than once, or in more than one data list in order to group certain related parameters together.

Use the Engine Scan Tool Data List only after the following conditions are determined

  1. The Diagnostic System Check - Vehicle is completed.
  2. There are no diagnostic trouble codes (DTCs).
  3. The On-Board diagnostics are functioning properly.

Scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents the values that would be seen on a normal running engine.

IMPORTANTDo not use a scan tool that displays faulty data. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and in unnecessary parts replacement.

The column labeled Data List indicates where a parameter is located on the scan tool. Review the scan tool operating manual for the exact locations of the data lists. The following is a description of each term listed

Scan Tool ParameterData ListParameter Range/UnitsTypical Data Values
Operating Conditions: Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop/Accessories Off
5-Volt Reference 1 or 2EVAP, IGN, IND, TACVolts4.5
5-Volt Reference 1 or 2 Circuit StatusEVAP, IGN, IND, TACOK/FaultOK
A/C Relay CommandENG, IND, MF, TACOn/OffOff
Air Flow CalculatedENG, EVAP, FT, HO2S, IND, MF, TACG/s
Ambient Air TemperatureENG, EVAP°C/°FVaries
APP Indicated AngleALL0-100%0.0
APP SensorsTACVolts0.0
APP Sensor 1TAC0.9-4.5 Volts0.92 Volt
APP Sensor 1 Indicated PositionTAC%0.0
APP Sensor 2TAC0.42-2.25 Volts0.43 Volt
APP Sensor 2 Indicated PositionTAC%0.0
APP Sensor 1 and 2TACAgree/DisagreeAgree
BAROENG, EVAP, FT, HO2S, IGN, IND65-104 kPa -16 psiVaries with altitude
BARO SensorINDVoltsVaries
BPP Circuit SignalTACApplied/ReleasedReleased
BPP SignalTACApplied/Released/InvalidReleased
CAC Int Pump Relay Circuit StatusINDOK/Incomplete/Open/Short B+/Short GndOK
CAC Int Pump Relay CommandINDOn/OffVaries
Calc. TWC Temp. Bank 1 or Bank 2FT, MF°C/°FVaries
Catalytic Converter Protection ActiveFT, HO2SYes/NoNo
CKP Active CounterIGNCountsIncrementing
CKP Resync CounterIGNCountsVaries
CKP SensorIGNRPMEngine idle speed
Cmmd. A/F Equivalence RatioENG, FT, HO2S, INDRatio14.7:1
CMP Active CounterCMP, IGNCountsIncrementing
CMP SensorCMP, IGN, MFRPMEngine idle speed
Cold StartupENG, EVAPYES/NOVaries
Cruise Control ActiveENG, TACActive/InactiveInactive
Cycles of Misfire DataMF0-99Incrementing
Cylinder 1-8 IC Circuit StatusMFIncomplete/Short B+/Short Gnd/ OpenOK
Cylinder 1-8 Injector Circuit StatusMFIncomplete/Short B+/Short Gnd/OpenOK
Decel. Fuel CutoffENG, FT, HO2SActive/InactiveInactive
Desired Exh. CMP Bank 1 or Bank 2CMPDegreesVaries
Desired Idle SpeedENG, CMP, EVAP, IND, TAC0-7,000 RPM650 RPM
Desired Int. CMP Bank 1 or Bank 2CMPDegreesVaries
Distance Since DTC ClearedENGMiles/KilometersVaries
EC Ignition Relay Circuit StatusTACOK/Incomplete/Short B+/Short Gnd/OpenOK
EC Ignition Relay CommandENG, TACOn/OffOn
EC Ignition Relay Feedback SignalENG, TACVolts13.5 V
ECT SensorALL39 to +140°C/-38 to +284°F85-105°C/185-220°F
Engine LoadALL0-99%2%
Engine Off TimeEVAP0:00:00Varies
Engine Oil Level SwitchENG, CMPOK/LowOK
Engine Oil Life RemainingENG, CMP%Varies
Engine Oil Pressure SensorENG, CMP, MFKPa/psiVaries
Engine Oil Temperature CalculatedCMP°C/°FVaries
Engine Oil Temperature Sensor (if equipped)CMP°C/°FVaries
Engine Run TimeALL0:00:00Varies
Engine SpeedALLRPM650 RPM
EVAP Fault HistoryEVAPVacuum/Purge Valve Leak/Small Leak/Weak Vacuum/No Test ResultVacuum
EVAP Purge Solenoid CommandENG, EVAP, FT, HO2S0-100%Varies
EVAP Purge Solenoid Circuit StatusEVAPIncomplete/Fault/OKIncomplete
EVAP Vent Solenoid CommandENG, EVAPVenting/Not VentingNot Venting
EVAP Vent Solenoid Circuit StatusEVAPIncomplete/Fault/OKIncomplete
Exh. CMP Angle Bank 1 or Band 2CMPDegreesVaries
Exh. CMP Bank 1 or Bank 2 Active CounterCMP, IGNCountsVaries
Exh. CMP Bank 1 or Bank 2 CommandCMP%Varies
Exh. CMP Bank 1 or Bank 2 VarianceCMPDegreesVaries
Ext. CMP Solenoid Bn 1 or Bn 2 Circuit StatusCMPOK/Incomplete/Short B+/Short Gnd/OpenOK
Ext. Travel BPP SignalTACApplied/Released/InvalidReleased
Fuel Level Sensor - Left TankEVAP0-5 VoltsVaries
Fuel Level Sensor - Right TankEVAP0-5 VoltsVaries
Fuel Pump Relay Circuit StatusENGIncomplete/Fault/OKOK
Fuel Pump Relay CommandENGOn/OffOn
Fuel Tank Level RemainingENG, EVAP, FT, MF%Varies
Fuel Tank Pressure SensorEVAPVoltsVaries
Fuel Tank Pressure SensorENG, EVAPIn H2O/mm HgVaries
Fuel Tank Rated CapacityEVAPLiters/GalVaries
Fuel Trim CellENG, FTVaries2
Fuel Trim LearnFTEnabled/DisabledEnabled
Fuel Trim System Test StateFTDisabled, Enabled, Run Purge Test, MonitoringVaries
Fuel VolatilityEVAP, FTLow/Moderate/HighVaries
HO2S Bank 1 or Bank 2 Sensor 1ENG, EVAP, FT, HO2S, INDMV80-850
HO2S Bank 1 or Bank 2 Sensor 2ENG, FT, HO2SMVVaries 400-800 mV
HO2S Bank 1 or Bank 2 Sensor 1 HeaterHO2SAmpsVaries
HO2S Bank 1 or Bank 2 Sensor 2 HeaterHO2SAmpsVaries
HO2S Bank 1 Sensor 1 Heater CommandHO2S%Varies
HO2S Bank 1 Sensor 1 Heater CommandHO2SON/OFFON
HO2S Bank 1 or Bank 2 Sensor 2 Heater CommandHO2S%Varies
HO2S Bank 1 or Bank 2 Sensor 2 Heater CommandHO2SON/OFFON
Hot Open LoopHO2S, FTActive/InactiveInactive
IAT SensorALL39 to +140°C/-38 to +284°FVaries
IAT Sensor 2ENG, EVAP, IND39 to +140°CVaries
Ignition Accessory SignalENG, TACON/OFFON
Ignition Off TimeENG, EVAP0:00:00Varies
Ignition 1 SignalALL0-25.5 Volts12.8-14.2 Volts
Injector PWM Bank 1 or Bank 2ENG, FT, HO2S, MF0-9 ms3.0-5.4 ms
Injector 1-8 Disabled Due To MisfireMFYes/NoNo
Int. CMP Angle Bank 1 or Bank 2CMPDegreesVaries
Int. CMP Bank 1 or Bank 2 Active CounterCMP, IGNCountsVaries
Int. CMP Bank 1 or Bank 2 CommandCMP%Varies
Int. CMP Bank 1 or Bank 2 VarianceCMPDegreesVaries
Int. CMP Solenoid Bn 1 or Bn 2 Circuit StatusCMPOK/Incomplete/Short B+/Short Gnd/OpenOK
Intake Manifold PressureENG, FT, INDKPaVaries
Knock Detected Cyl.1-8IGNYES/NONO
Knock RetardIGN0-191 Degrees0
Long Term FT Bank 1 or Bank. 2ENG, EVAP, FT, HO2S100 to +100%7-9%
LT FT Test Avg. Bank 1 or Bank 2FT%1%
LT FT Avg. Bank 1 or Bank 2 w/o purgeFT%1%
Loop StatusENG, EVAP, FT, HO2SOpen/ClosedClosed
MAF Performance TestFT, TAC, INDOK/FaultOK
MAF SensorALL0-655 g/s3-7 g/s
MAF SensorIND0-9999 Hz28 Hz
MAP Performance TestFT, IND, TACOK/FaultOK
MAP Performance Test 1FT, IND, TACOK/FaultOK
MAP Performance Test 2FT, IND, TACOK/FaultOK
MAP SensorALLKPa/psi30 kPa (4.6 psi)
MAP SensorINDVolts1.06
MIL Circuit StatusENGOK/Incomplete/Short B+/Short GndOK/Incomplete
MIL CommandENGOn/OffOff
MIL Requested by DTCALLYes/NoNo
Misfire Current Cyl. 1-8MF0-255 Counts0
Misfire History Cyl. 1-8MF0-255 Counts0
PNP SwitchENGPark/Neutral/In GearPark/Neutral
Power EnrichmentENG, FT, HO2S, MFActive/InactiveInactive
Reduced Engine PowerTACActive/InactiveInactive
SC Inlet Pressure SensorFT, INDKPa/psiVaries
SC Inlet Pressure SensorINDVoltsVaries
SC Inlet PressureFT, INDKPa/psiVaries
SCB Solenoid Circuit StatusINDOK/Incomplete/Short B+/Short Gnd/OpenOK
SBC Solenoid CommandENG, IND%Varies
Short Term FT Bank 1 or Bank 2ENG, EVAP, FT, HO2S100 to +100%3% to +3%
SparkENG, FT, HO2S, IGN, IND, MF°
Start Up ECTEVAP, HO2S39 to +140°C/-38 to +284°FVaries
Start Up IATEVAP, HO2S39 to +140°C/-38 to +284°FVaries
ST FT Test Avg. Bank 1 or Bank 2FT%
TAC Forced Engine ShutdownTACYES/NONO
TAC MotorTACEnabled/DisabledEnabled
TAC Motor CommandTAC%
TCS Torque Delivered SignalTAC%1 %
TCS Torque Request SignalTACNm
TCS Torque Request SignalTAC%
Torque Management Spark RetardIGN°0
Total Knock RetardIGN°0
Total MisfireMF0-99990
TP Desired AngleTAC%2 %
TP Indicated AngleALL0-99%2-3 %
TP Performance TestIND, TAC, FTOK/FaultOK
TP Sensor 1TAC0-5 Volts0.5-0.8 Volts
TP Sensor 2TAC0-5 Volts4.1-4.5 Volts
TP Sensor 1 Indicated PositionTAC%2 %
TP Sensor 2 Indicated PositionTAC%2 %
TP Sensor 1 Learned MinTAC0-5 VoltsVaries
TP Sensor 2 Learned MinTAC5-0 VoltsVaries
TP Sensors 1 and 2TACAgree/DisagreeAgree
Vehicle Speed SensorALLKm/mi0
Warm-ups Since DTC ClearedENGCounts0
Warm-ups w/o Emission FaultsENGCounts0
Warm-ups w/o Non-emission FaultsENGCounts0
Wide Open ThrottleTACYES/NONO

Scan Tool Data List

Scan Tool Data Definitions

The Scan Tool Data Definitions list contains a brief description of all of the engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists. In some cases the parameter may appear more than once, or in more than one data list in order to group certain related parameters together.

Scan Tool Output Controls

Scan Tool Output ControlAdditional Menu Selection(s)Description
CAC Coolant Pump Relay CommandOutput ControlsThis function activates the charge air cooler (CAC) coolant pump relay. The normal commanded state is NONE. When commanded ON or OFF, the engine control module (ECM) turns the relay ON or OFF. The system remains in the commanded state until cancelled by the scan tool.
Cylinder Power BalanceFuel SystemEnables/Disables a cylinder by turning OFF the fuel injector to the cylinder. The fuel injector is normally enabled. The ECM disables the fuel injector when the following conditions are met: All instructions on the scan tool have been completed. Stabilized engine speed Fuel injector selected When the DISABLE is selected the ECM turns the injector OFF for 30 seconds. During this period, the engine operates with a misfire.
Engine Controls Ignition RelayOutput ControlsThis function activates the engine control ignition relay. The normal commanded state is NONE. When commanded ON or OFF, the ECM turns the relay ON or OFF. The system remains in the commanded state until cancelled by the scan tool.
Engine Speed ControlTAC SystemActivates the throttle activation control (TAC) system to change engine speed. The normal commanded state is None. To enable the engine speed control, all instruction on the scan tool must be completed. The system will increase or decrease the engine speed within a range of 400-2,200 RPM. The set step value changes the engine speed by increments of 25 RPM, 100 RPM, and 500 RPM. The system remains in the commanded state until cancelled by the scan tool.
EVAP Purge SolenoidOutput Controls/EVAP SystemActivates the EVAP purge valve. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of EVAP purge valve opening by 10 percent increments within a range of 0-100 percent. The system remains in the commanded state until cancelled by the tool or the fuel tank pressure exceeds 24 mm Hg (12 in H20).
EVAP Purge/SealOutput Controls/EVAP SystemThis control enables 2 functions. One function increases or decreases the amount of purge by changing the duty cycle of the purge valve and commanding the vent ON (non-venting). The normal commanded state of both valves is NONE. The system will INCREASE or DECREASE the amount of EVAP purge valve opening by 10 percent increments within a range of 0-100 percent. The second function seals the system after using the purge function to obtain a specific amount of fuel tank pressure (FTP). When activated the purge valve is commanded to 0 percent and the vent valve is commanded ON (non-venting). Both functions remain in the commanded state until cancelled by the tool or the FTP exceeds 24 mm Hg (12 in H20).
EVAP Service Bay TestService Bay TestsActivates the Service Bay Test to verify the integrity of the EVAP System. The scan tool initiates the test when the following conditions are met: All instructions on the scan tool have been completed. The engine coolant temperature is less than a specified value. No DTCs are set.
EVAP Vent SolenoidOutput Controls/EVAP SystemActivates the EVAP vent solenoid. The normal commanded state is NONE. When commanded ON, the vent valve switches to non-venting. The system remains in the commanded state unless one of the following conditions occurs: Cancelled by the tool Purge is greater than 0 percent, and the fuel tank pressure exceeds 24 mm Hg (12 in H20)
Exhaust CMP Actuator Bank 1CMP Actuator SystemThis function controls the exhaust camshaft actuator for bank 1. The normal commanded state is NONE. The system will increase or decrease the angle of the selected camshaft in 5 degree increments up to 25 crankshaft degrees. The scan tool initiates the test when the following conditions are met: The vehicle speed is 0 km/h (0 mph). The transmission is in Park or Neutral. The engine speed is between 1,000-1,400 RPM. The system remains in the commanded state until cancelled by the scan tool.
Exhaust CMP Actuator Bank 2CMP Actuator SystemThis function controls the exhaust camshaft actuator for bank 2. The normal commanded state is NONE. The system will increase or decrease the angle of the selected camshaft in 5 degree increments up to 25 crankshaft degrees. The scan tool initiates the test when the following conditions are met: The vehicle speed is 0 km/h (0 mph). The transmission is in Park or Neutral. The engine speed is between 1,000-1,400 RPM. The system remains in the commanded state until cancelled by the scan tool.
Exh. CMP Actuator Sol. Bank 1CMP Actuator SystemThis function controls the exhaust camshaft actuator solenoid for bank 1. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the camshaft actuator solenoid ON/OFF. The scan tool initiates the test when the following conditions are met: The ignition is ON with the engine OFF. No engine speed is detected. The system remains in the commanded state until cancelled by the scan tool.
Exh. CMP Actuator Sol. Bank 2CMP Actuator SystemThis function controls the exhaust camshaft actuator solenoid for bank 2. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the camshaft actuator solenoid ON/OFF. The scan tool initiates the test when the following conditions are met: The ignition is ON with the engine OFF. No engine speed is detected. The system remains in the commanded state until cancelled by the scan tool.
Fuel Injector BalanceFuel SystemEnables fuel injector in order to verify proper fuel injector flow. The ECM also enables the fuel pump. The ECM will pulse the selected injector when the following conditions are met: All instructions on the scan tool have been completed. Fuel injector selected Key ON, engine OFF The selected fuel injector can only be flowed/pulsed once per ignition cycle.
Fuel PumpOutput ControlsControls the fuel pump relay. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the fuel pump ON/OFF. If the engine is running, and the fuel pump is commanded OFF, the engine will stall. The system remains in the commanded state until cancelled by the scan tool.
Fuel Trim EnableFuel SystemDisables the ECMs ability to learn new fuel trim parameters. The commanded states are NONE, ENABLED, DISABLED. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the scan tool.
Fuel Trim ResetFuel SystemThis function activates the reset of fuel trim data in all fuel trim cells.
HO2S Bank 1 Sensor 1 HeaterOutput Controls/Heated Oxygen SensorsActivates the HO2S bank 1 sensor 2 heater. The ECM commands the heater on in 10% increments from 0% to 100%. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.
HO2S Bank 1 Sensor 2 HeaterOutput Controls/Heated Oxygen SensorsActivates the HO2S bank 1 sensor 2 heater. The ECM commands the heater on in 10% increments from 0% to 100%. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.
HO2S Bank 2 Sensor 1 HeaterOutput Controls/Heated Oxygen SensorsActivates the HO2S bank 1 sensor 2 heater. The ECM commands the heater on in 10% increments from 0% to 100%. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.
HO2S Bank 2 Sensor 2 HeaterOutput Controls/Heated Oxygen SensorsActivates the HO2S bank 1 sensor 2 heater. The ECM commands the heater on in 10% increments from 0% to 100%. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.
Idle SparkOutput Controls/Spark ControlDisables and enables idle spark advance with the engine running.
Intake CMP Actuator Bank 1CMP Actuator SystemThis function controls the intake camshaft actuator for bank 1. The normal commanded state is NONE. The system will increase or decrease the angle of the selected camshaft in 5 degree increments up to 20 crankshaft degrees. The scan tool initiates the test when the following conditions are met: The vehicle speed is 0 km/h (0 mph). The transmission is in Park or Neutral. The engine speed is between 1,000-1,400 RPM. The system remains in the commanded state until cancelled by the scan tool.
Intake CMP Actuator Bank 2CMP Actuator SystemThis function controls the intake camshaft actuator for bank 2. The normal commanded state is NONE. The system will increase or decrease the angle of the selected camshaft in 5 degree increments up to 20 crankshaft degrees. The scan tool initiates the test when the following conditions are met: The vehicle speed is 0 km/h (0 mph). The transmission is in Park or Neutral. The engine speed is between 1,000-1,400 RPM. The system remains in the commanded state until cancelled by the scan tool.
Int. CMP Actuator Sol. Bank 1CMP Actuator SystemThis function controls the intake camshaft actuator solenoid for bank 1. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the camshaft actuator solenoid ON/OFF. The scan tool initiates the test when the following conditions are met: The ignition is ON with the engine OFF. No engine speed is detected. The system remains in the commanded state until cancelled by the scan tool.
Int. CMP Actuator Sol. Bank 1CMP Actuator SystemThis function controls the intake camshaft actuator solenoid for bank 2. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the camshaft actuator solenoid ON/OFF. The scan tool initiates the test when the following conditions are met: The ignition is ON with the engine OFF. No engine speed is detected. The system remains in the commanded state until cancelled by the scan tool.
Loop StatusOutput ControlsControls the system loop status. The commanded states include NONE, OPEN, or CLOSED. The normal commanded state is NONE. When commanded OPEN or CLOSED, the system remains in the commanded state until cancelled by the scan tool.
Malfunction Indicator LampOutput ControlsControls the malfunction indicator lamp (MIL). The commanded states include NONE, ON, and OFF. When commanded ON or OFF, the system remains in the commanded state until cancelled by the scan tool.
Misfire GraphicMisfire GraphicGraphs the accumulated misfires occurring in each cylinder. The scan tool allows for a reset of the misfire graph.
SCB SolenoidOutput ControlsActivates the solenoid from the none, increase, and decrease in increments and decrements by 10%. The range is 0-100%.
Spark RetardOutput Controls/Spark ControlControls the amount of spark retard. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of spark retard by 1 degree increments within a range of 0-10 degrees maximum retard. The system remains in the commanded state until cancelled by the tool.
Throttle PositionTAC SystemThis function opens the throttle plate in 25 percent increments. The scan tool initiates the test when the following conditions are met: The ignition is ON, with the engine OFF. The vehicle speed is 0 km/h (0 mph). The system remains in the commanded state until cancelled by the scan tool.

Scan Tool Output Controls