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Engine Control System - 3.6l (ly7) - Introduction (1 of 2) Cadillac SRX I

Diagnostic Starting Point - Engine Controls

Begin the system diagnosis with Diagnostic System Check - Vehicle in Vehicle DTC Information. 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 DTCs and the codes status

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 correctly.

Scan tool values from an engine that is operating correctly 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 operating 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 may result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service information for use in diagnosis. If all values are within the typical range described below, refer to Symptoms - Engine Controls for diagnosis.

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
Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop/Accessories Off
A/C Disengage 1-8 HistoryCHReason for A/C DisengagementVaries
A/C High Side Pressure SensorCH0-5 VoltsVaries
A/C High Side Pressure SensorCHKPa/psiVaries
A/C OFF for WOTCHYes/NoNo
A/C Pressure DisableCHYes/NoNo
A/C Relay Circuit StatusCH, ODMOK/Fault/IndeterminateOK
A/C Relay CommandEng, MF, CHOn/OffOff
A/C Request SignalCHYes/NoNo
APP Indicated AngleEng, Ign, CMP, CT, EVAP, HO2S, FT, TAC, Trans0-100%0%
APP Sensor 1TAC0.9-4.5 Volts1 Volt
APP Sensor 2TAC0.40-2.25 Volts0.4 Volt
APP Sensor 1 and 2TACAgree/DisagreeAgree
BAROEng, Ign, CMP, EVAP, HO2S, IM, FT, MF, TAC65-104 kPa (8-16 psi)Varies with altitude
BAROEng, TAC, TransVoltsVaries
Brake Pedal Signal StatusCT, TAC, TransValid/InvalidValid
Calculated ECT - Closed Loop Fuel ControlCH39°C to +40°C (-38°F to +104°F)40°C (104°F)
Calculated ECT - Thermostat DiagnosisCH39°C to +140°C (-38°F to +284°F)89°C (192°F)
Calc. TWC Temp. Bank 1 and 2FT, MFTemperatureVaries
Catalytic Converter Protection ActiveFT, MFYes/NoNo
Catalyst Monitor Complete This IgnitionIMYes/NoVaries
Catalyst Monitor Enabled this IgnitionIMYes/NoVaries
CKP Resync CounterIgn, MFCounts0 Counts
Clutch Start Switch (If Equipped)IM, TransOn/OffDepends on position of clutch pedal
Component Monitor Complete This IgnitionIMYes/NoVaries
Component Monitor Enable This IgnitionIMYes/NoVaries
CPP Switch (If Equipped)IM, TransApplied/ReleasedDepends on position of clutch pedal
Crank Request SignalETYes/NoNo
Cruise Control ActiveCT, IPCYes/NoNo
Cruise Disengage 1-8 HistoryCTReasonVaries
Cruise Inhibit ReasonCTReasonVaries
Cruise On/Off SwitchCTOn/OffOff
Cruise Resume/Accel. SwitchCTOn/OffOff
Cruise Set/Coast SwitchCTOn/OffOff
Current GearEng, CT, ET, IPC, FT, MFP/N/Reverse/1st-5thP/N
Current Gear SignalET, TransValid/InvalidValid
Cycles of Misfire DataMF0-200 countsVaries
Cylinder 1-6 Injector Circuit StatusODMOK/Fault/IndeterminateOK
Cylinder 1-6 Knock RetardIgnDegree0 Degrees
Decel. Fuel CutoffEng, FT, HO2SActive/InactiveInactive
Desired Exh. CMP Bank 1 or 2CMPDegreeVaries
Desired HO2S Bank 1 or 2 Sensor 1HO2SLambdaVaries
Desired Idle SpeedEng, EVAP, CMP, TAC0-7,000 RPM650 RPM
Desired Int. CMP Bank 1 or 2CMPDegreesVaries
DTC Set This IgnitionEng, Ign, CMP, EVAP, FT, HO2S, TACYes/NoNo
EC Ignition Relay CommandEng, TAC, ETOn/OffOn
EC Ignition Relay Feedback SignalEng, TAC, ET0-25.5 Volts12.0-14.5 Volts
ECM ResetEng, Ign, EVAP, FTYes/NoNo
ECT SensorEng, Ign, CMP, EVAP, HO2S, FF, FR, FT, MF, TAC, CH, IM, IPC, Trans39°C to +140°C (-38°F to +284°F)Varies
Engine LoadEng, Ign, CMP, EVAP, HO2S, FF, FR, FT, MF, TAC, CH, Trans0-99%25-45% - Idle 40-60% - 2500 RPM
Engine OFF EVAP Test Conditions MetEVAPYes/NoVaries
Engine Off TimeEVAP, IM0:00:00 SecondsVaries
Engine Oil Level SwitchEng, CMP, IPCOK/LowOK
Engine Oil Life RemainingCMP, IPC%Varies
Engine Oil Pressure SensorIPCOK, LowOK
Engine Oil Pressure SensorEng, MF, CMP, IPCKPa/psiVaries
Engine Oil Pressure SensorIPC, MF1-5 VoltsVaries
Engine Run TimeEng, Ign, ET, EVAP, FT, HO2S, MF, TAC, CMP, ODM, CH, CT, IM0:00:00Varies
Engine SpeedALLRPM575-700 RPM
EVAP Monitor Complete This IgnitionIMYes/NoVaries
EVAP Monitor Enabled This IgnitionIMYes/NoVaries
EVAP Purge Solenoid Circuit StatusODMOK/Fault/IndeterminateOK
EVAP Purge Solenoid CommandEng, EVAP, FT0-100%Varies
EVAP Vent Solenoid Circuit StatusODMOK/Fault/IndeterminateOK
EVAP Vent Solenoid CommandEng, EVAP, FTVenting/Not VentingVenting
Exh. CMP Angle Bank 1 or 2Eng, CMPDegreesVaries
Exh. CMP Angle Bank 1 or 2 VarianceCMPDegreesVaries
Exh. CMP Bank 1 or 2 CommandCMP0-99%Varies
Exh. CMP Solenoid Bn. 1 or 2 Circuit StatusODMOK/Fault/IndeterminateOK
Extended Travel Brake Pedal SwitchEng, TAC, CTApplied/ReleasedReleased
FC Relay 1 Circuit StatusCH, ODMOK/Fault/IndeterminateOK
FC Relay 1 CommandCHON/OFFVaries
FC Relay 2 and 3 CommandCHON/OFFVaries
FC Relay 2 and 3 Circuit StatusCH, ODMOK/Fault/IndeterminateOK
Fuel LevelEVAP0-100 %Varies
Fuel Level Sensor Left Tank (Secondary)EVAP, IPC0-5 VoltsVaries
Fuel Level Sensor Right Tank (Primary)EVAP, IPC0-5 VoltsVaries
Fuel Pump Relay Circuit StatusODMOK/Fault/IndeterminateOK
Fuel Pump Relay CommandEngOn/OffOn
Fuel Tank Level RemainingEng, EVAP, IPC, MF, IMLiter/GallonVaries
Fuel Tank Pressure SensorEVAPIn H2O/mm HgVaries
Fuel Tank Pressure SensorEng, EVAP0-5 VoltsVaries
Fuel Tank Rated CapacityEVAPLiter/Gallon17.8 Gallons (67.3 Liters)
Fuel Trim LearnEng, EVAP, FT, HO2SEnabled/DisabledEnabled
GEN L-Terminal Signal CommandET0-100%Varies
Generator F-Terminal SignalET0-100%Varies
HO2S Bank 1 or 2 Sensor 1Eng, EVAP, FT, HO2SLambda1.0 Lambda
HO2S Bank 1 or 2 Sensor 2Eng, FT, HO2S0-1,006 mVVaries 400-700 mV
HO2S Heater Monitor Complete This IgnitionIMYes/NoVaries
HO2S Heater Monitor Enabled This IgnitionIMYes/NoVaries
HO2S Htr. Bn. 1 or 2 Sensor 1 or 2 Circuit StatusODMOK/Fault/IndeterminateOK
HO2S Htr. Bn. 1 or 2 Sensor 1 CommandHO2S0-99%Varies
HO2S/O2S Monitor Complete This IgnitionIMYes/NoVaries
HO2S/O2S Monitor Enabled This IgnitionIMYes/NoVaries
HO2S Sensing Element Bn. 1 or 2 Sensor 1HO2SOhms70-90 Ohms Depends on Temperature
HO2S Sensing Element Bn. 1 or 2 Sensor 2HO2SOhms20-300 Ohms Depends on Temperature
IAT SensorEng, Ign, EVAP, FT, FF, FR, HO2S, IM, TAC, CMP, CH, Trans39° to +140°C (-38° to +284°F)Varies
Ignition 0 SignalEng, Ign, EVAP, TAC, ET, IM, IPC, TransOn/OffOn
Ignition 1 SignalEng, Ign, EVAP, FT, MF, TAC, CMP, ET, IM, IPC, TransOn/OffOn
IMRC Solenoid Circuit StatusODMOK/Fault/IndeterminateOK
IMRC Solenoid CommandEngOn/OffOff
Initial Brake Apply SignalTAC, CTApplied/ReleasedReleased
Injector 1-6 CommandFT, MFMsVaries
Injector PWM Bank 1 or 2 AverageFT, MF0-9 ms4.6-5.4 ms
Int. CMP Angle Bank 1 or 2Eng, CMPDegreesVaries
Int. CMP Angle Bank 1 or 2 VarianceCMPDegreesVaries
Int. CMP Bank 1 or 2 CommandCMP0-99%Varies
Int. CMP Solenoid Bn. 1 or 2 Circuit StatusODMOK/Fault/IndeterminateOK
Knock RetardEng, Ign, CHDegreesVaries
KS 1 or 2 SignalIgnVoltsVaries
Loop Status Bn 1 or 2 Sen. 1Eng, EVAP, FT, HO2S, FF, FROpen Loop/Closed LoopClosed Loop
Loop Status Bn 1 or 2 Sen. 2Eng, EVAP, FT, HO2S, FF, FROpen Loop/Closed LoopOpen Loop
LT FT Bn. 1 or Bn. 2 Cruise/Accel.Eng, EVAP, FT, HO2S100% to +100%0%
LT FT Bn. 1 or Bn. 2 Idle/Decel.Eng, EVAP, FT, HO2S100% to +100%0%
MAF SensorEng, Ign, FT, HO2S, MF, TAC, CMP, FF, FR, Trans0-655 g/s3.4-6.3 g/s
MAF SensorEng, Ign, EVAP, FT, HO2S, MF, TAC, CMP, Trans0-5 Volts0.9-1.7 Volts
MIL Circuit StatusIPC, ODMOK/Fault/IndeterminateOK
MIL CommandEng, EVAP, IM, IPC, TransOn/OffOff
Mileage Since DTC ClearedFF, FRKm - milesVaries
Mileage Since First FailureFF, FRKm - milesVaries
Mileage Since Last FailureFF, FRKm - milesVaries
Mileage Since MIL RequestedFF, FRKm - milesVaries
Misfire Current Cyl. 1-6MF0-255 Counts0
Misfire History Cyl. 1-6MF0-65,535 Counts0
Misfire Monitor Complete This IgnitionIMYes/NoVaries
Misfire Monitor Enabled This IgnitionIMYes/NoVaries
Moderate Brake Apply SignalTAC, CTApplied/ReleasedReleased
PNP SwitchEng, ET, TransPark/Neutral/In GearP/N
Power EnrichmentEng, FT, HO2S, MFActive/InactiveInactive
PRNDLTransD1, D2, D3, D4, D5, Neutral, Park, ReversePark/Neutral
Reduced Engine PowerEng, TAC, IPCActive/InactiveInactive
Short Term FT Bank 1 or Bank 2Eng, EVAP, FT, HO2S, FF, FR25% to +25%3% to +3%
SparkEng, Ign, FT, HO2S, MF, CH, CT, FF, FR20 to +40 Degrees2-10 Degrees
Starter Relay Circuit StatusET, ODMOK/Fault/IndeterminateOK
Starter Relay CommandETOn/OffOff
Start Up ECTEVAP, FT, HO2S, CH, IM39° to +140°C (-38° to +284°F)Varies
Start Up IATEVAP, FT, HO2S, CH, IM39° to +140°C (-38° to +284°F)Varies
Stoplamp Pedal SwitchEng, CT, TACApplied/ReleasedReleased
System Power ModeEVAP, TAC, ETOff, Accessory, RAP, Run, or Crank RequestRun
TAC System Learned CountsTAC0-11 Counts0
TCC Brake Pedal SwitchCT, IM, TransApplied/ReleasedReleased
TCC StatusEng, MF, TransLocked/UnlockedUnlocked
TCM Requested TorqueCT, TAC, TransN.m/lb ftVaries
TCM Torque IncreaseCT, TAC, TransYes/NoNo
TCS Torque IncreaseCT, TACYes/NoNo
TCM Torque Reduction ActiveCT, TAC, TransYes/NoNo
TCS Torque Reduction ActiveCT, TACYes/NoNo
Torque Delivered SignalFT, TAC, CT0-100%Varies
Torque Request SignalFT, TAC, CT0-100%90-98%
Total Fuel Trim Avg. Bank 1 or Bank 2EVAP, FT, HO2S100 to +100%Varies
Total Misfire CountMFCounts0
TP Desired AngleEng, EVAP, TAC, CT0-100%Varies
TP Indicated AngleEng, Ign, EVAP, FT, HO2S, MF, TAC, CMP, CT, FF, FR, Trans0-100%Varies
TP Sensor 1TAC0-5 Volts0.5-0.8 Volts
TP Sensor 1 Learned MinimumTAC0-5 Volts0-0.6 Volts
TP Sensor 2TAC0-5 Volts4.7-4.1 Volts
TP Sensor 2 Learned MinimumTAC0-5 Volts5-3.7 Volts
TP Sensors 1 and 2TACAgree/DisagreeAgree
Traction Control StatusTAC, CTActive/InactiveInactive
Transmission Gear Selector SignalTransValid/InvalidValid
Vehicle Security StatusET, IPCPassword Learning, VTD Fail-Enable, Auto Learn Timer, Fuel Disable Until Ign Off, Fuel Disable Timeout, and Fuel ContinueFuel Continued
Vehicle Speed SensorEng, Ign, EVAP, FT, HO2S, MF, TAC, CMP, CH, CT, IM, IPC, FF, FR, TransKm/h mphVaries
Volumetric EfficiencyEng, Ign, EVAP, FT, HO2S, MF, TAC, CMP, CH, Trans0-100%5-25% - Idle and at 2,500 RPM

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
Camshaft ActuatorSpecial Functions/Engine Output Controls/CMP Actuator SystemThis function controls the selected camshaft actuator. The normal commanded state is NONE. The system will increase or decrease the angle of the selected camshaft in 5 degree increments up to 40 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.
Camshaft Actuator SolenoidSpecial Functions/Engine Output Controls/CMP Actuator SystemThis function controls the selected camshaft actuator solenoid. The normal commanded state is NONE. When commanded ON/OFF, the engine control module (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.
Cylinder Power BalanceSpecial Functions/Fuel SystemIMPORTANT: The Misfire Current and Misfire History parameters may not increment when using this function. This function disables the selected fuel injector. The normal commanded state is None. The scan tool initiates the test when the following conditions are met: The engine is operating and the engine idle is stable. The vehicle speed is 0 km/h (0 mph). There are no DTCs set for the vehicle speed sensor. If the fuel injector was disabled for 30 seconds, fuel injector control is not allowed again on the same fuel injector for 60 seconds.
Engine Speed ControlSpecial Functions/TAC SystemThis function controls the idle speed override in 25 RPM, 100 RPM, and 500 RPM increments, from the base idle speed to 1,400 RPM. The scan tool initiates the test when the following conditions are met: The transmission is in park or neutral. The engine speed is less than 1,000 RPM. The engine speed will remain in the commanded state until cancelled by the scan tool.
EVAP Purge SolenoidSpecial Functions/Engine Output Controls/EVAP SystemIMPORTANT: The EVAP Purge Solenoid Command parameter may not change states when using this output control. This function controls the evaporative emission (EVAP) purge solenoid valve. The normal commanded state is NONE. The system will increase or decrease the amount of purge by changing the duty cycle of the purge valve in 10 percent increments within a range of 0-100 percent. The system remains in the commanded state until cancelled by the scan tool or the fuel tank pressure (FTP) sensor exceeds -24 mm Hg (-12 in H2O).
EVAP Purge/SealSpecial Functions/Engine Output Controls/EVAP SystemIMPORTANT: The EVAP Purge and Vent Solenoid Command parameters may not change states when using this output control. This function activates both the EVAP purge solenoid valve and EVAP vent solenoid to seal the EVAP system. When activated, the purge valve is commanded to 0 percent and the vent valve is commanded ON, Not-venting. The normal commanded state for both solenoids is None. Both of the solenoids remain in the commanded state until cancelled by the scan tool or the FTP sensor exceeds -24 mm Hg (-12 in H2O).
EVAP TestService Bay TestThis function activates 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. ECT is less than a specified value. No EVAP DTCs are set.
EVAP Vent SolenoidSpecial Functions/Engine Output Controls/EVAP SystemIMPORTANT: The EVAP Vent Solenoid Command parameter may not change states when using this output control. This function controls the EVAP vent solenoid. The normal commanded state is NONE. When commanded ON, the vent valve switches to Not-venting. The system remains in the commanded state unless one of the following conditions occur: Cancelled by the scan tool The EVAP canister purge solenoid is more than 0 percent, and the FTP sensor exceeds -24 mm Hg (-12 in H2O).
Fuel Injector BalanceSpecial Functions/Fuel SystemThis function enables the fuel injector in order to verify the correct fuel injector flow. The ECM will pulse the selected fuel injector when the following conditions are met: All instruction on the scan tool is complete. A fuel injector is selected. The ignition is ON with the engine OFF. The selected fuel injector can only be flowed/pulsed once per ignition cycle.
Fuel PumpSpecial Functions/Engine Output ControlsThis function controls the fuel pump relay. The normal commanded state is NONE. The scan tool initiates the test when the following conditions are met: There are no vehicle speed sensor DTCs set. The vehicle speed is 0 km/h (0 mph). When commanded ON/OFF, the ECM turns the fuel pump relay ON/OFF. If the engine is running and the fuel pump relay is commanded OFF, the engine will stall. The system remains in the commanded state for about 2 seconds or until cancelled by the scan tool or the ECM detects a vehicle speed.
Fuel Trim ResetSpecial Functions/Fuel SystemThis function resets the fuel trim data and the learned values for the rear heated oxygen sensors.
Idle Learn ResetSpecial Functions/TAC SystemThis function allows the throttle position and the idle speed to be relearned by the ECM, once the following conditions have been met. The ignition is ON with the engine OFF. The engine coolant temperature (ECT) is between 5-85°C (41-185°F). No TAC system DTCs are set.
IMRC SolenoidSpecial Functions/Engine Output ControlsThis function controls the intake manifold runner control (IMRC) solenoid. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the IMRC solenoid ON/OFF. The scan tool initiates the test when the following conditions are met: There are no vehicle speed sensor DTCs set. The vehicle speed is 0 km/h (0 mph). The system remains in the commanded state until cancelled by the scan tool.
Loop StatusSpecial Functions/Engine Output ControlsThis function controls the heated oxygen sensor (HO2S) loop status. The commanded states include NONE, OPEN, and CLOSED. The normal commanded state is NONE. The loop status changes as commanded, OPEN or CLOSED. The system remains in the commanded state until cancelled by the scan tool.
Malfunction Indicator LampSpecial Functions/Engine Output ControlsThis function controls the malfunction indicator lamp (MIL). The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the MIL ON/OFF. The system remains in the commanded state until cancelled by the scan tool.
Throttle PositionSpecial Functions/TAC SystemThis function controls the throttle valve in 10 percent increments. The scan tool initiates the test when the following conditions are met: There are no vehicle speed sensor DTCs set. The vehicle speed is 0 km/h (0 mph). The ignition is ON, with the engine OFF. The ECM is not commanding a throttle learn. The system remains in the commanded state until cancelled by the scan tool.
IMPORTANT
The Misfire Current and Misfire History parameters may not increment when using this function.
IMPORTANT
The EVAP Purge Solenoid Command parameter may not change states when using this output control.
IMPORTANT
The EVAP Purge and Vent Solenoid Command parameters may not change states when using this output control.
IMPORTANT
The EVAP Vent Solenoid Command parameter may not change states when using this output control.

Scan Tool Output Controls