Engine Controls - 4.4l - DTC p0010 to p0175 Cadillac XLR I

Circuit Description

The camshaft position (CMP) actuator system is comprised of 4 CMP actuator solenoids, 4 oil control valves, and 4 CMP actuators. The engine control module (ECM) sends an electrical signal through the control circuits to the CMP actuator solenoids when a cam timing change is desired. The ground circuits of the CMP actuator solenoids are used as a return. If the ECM detects incorrect voltage on one of these circuits, DTC P0010, P0013, P0020, P0023 sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P0010 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Bank 1
2. DTC P0013 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Bank 1
3. DTC P0020 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Bank 2
4. DTC P0023 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Bank 2

Conditions for Running the DTC

1. DTC P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095 are not set.
2. The engine is running.
3. The CMP actuator has been commanded for more than 1 second.
4. The ignition voltage is between 11-26 volts.
5. This diagnostic runs continuously.

Conditions for Setting the DTC

1. The ECM detects incorrect voltage on a CMP actuator solenoid control or ground circuit.
2. The above condition is met for more than 1.6 seconds.

Action Taken When the DTC Sets

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

The CMP actuator system will be disabled until the end of the ignition cycle.

Conditions for Clearing the MIL/DTC

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0010, P0013, P0020 or P0023

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

DTC P0011, P0014, P0021 or P0024

Circuit/System Description

The camshaft position (CMP) actuator system is comprised of 4 CMP actuator solenoids, 4 oil control valves, and 4 CMP actuators. The engine control module (ECM) sends an electrical signal to the CMP actuator solenoids through the control circuits when a camshaft timing change is desired. The ground circuits of the CMP actuator solenoids are used as a return. The CMP actuator solenoid uses electromagnetic force to pull on the plunger of the oil control valve. The oil control valve will port the pressurized engine oil to either the advancing or retarding chambers of the CMP actuator. The CMP actuator, in turn, changes the CMP relative to the crankshaft position (CKP). If the desired CMP does not match the actual CMP for a calibrated amount of time, DTC P0011, P0014, P0021 or P0024 will set.

1. DTCs P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095 are not set.
2. The CMP actuators are commanded.
3. The engine oil pressure (EOP) is between 100-696.4 kPa (14.5-101 psi).
4. The engine speed is at an RPM between 1,000-6,500 RPM, that will allow for steady activation of the cam actuators based on calculated engine oil temperature (EOT).
5. The calculated EOT is between -10°C to +150°C (+14°F to +302°F).
6. The ignition voltage is between 9-18 volts.
7. DTC P0011, P0014, P0021 P0024 runs continuously when the above conditions are met.

The ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 6 degrees for more than 1.6 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the DTC

1. The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)

Circuit/System Verification

If DTCs P0010, P0013, P0020, P0023 are set, diagnose those DTCs first.

Circuit/System Testing

1. Measure the CMP actuator solenoid for the following specified resistance for the given temperature. 3.25-3.66 ohms at 40°C (40°F) 4.0-4.5 ohms at 20°C (68°F) 4.0-4.52 ohms at 25°C (77°F) 5.6-6.4 ohms at 125°C (257°F) If the resistance is not at the specified value for the given temperature replace the affected CMP actuator solenoid.
2. Disconnect the ECM. Test the affected CMP actuator solenoid control circuit for less than 2.5 ohms of resistance. If the resistance is more the 2.5 ohms repair the circuit as needed.
3. Test the affected CMP actuator solenoid ground circuit for less than 2.5 ohms of resistance. If the resistance is more the 2.5 ohms repair the circuit as needed.
4. Inspect for the following conditions Degraded oil quality, incorrect oil viscosity, and improper oil level Improper alignment of the CMP actuator solenoid to the oil control valve Low engine oil pressure Oil pressure leaks and restrictions in the dedicated oil passages from the oil filter to the affected CMP actuator A slow moving or sticking oil control valve A loose primary or secondary timing chain If no condition is found, replace the ECM.

Component Testing

Measure the CMP actuator solenoid for the following specified resistance for the given temperature.

1. 3.25-3.66 ohms at 40°C (40°F)
2. 4.0-4.5 ohms at 20°C (68°F)
3. 4.0-4.52 ohms at 25°C (77°F)
4. 5.6-6.4 ohms at 125°C (257°F) If the resistance is not at the specified value for the given temperature replace the affected CMP actuator solenoid.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming.
2. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Intake»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Exhaust»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
4. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 2 (Left Side) Intake»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
5. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 2 (Left Side) Exhaust»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

The camshaft position (CMP) actuator system enables the engine control module (ECM) to change the timing of the camshafts while the engine is operating. The ECM sends an electrical signal to the CMP actuator solenoids through the control circuits when a camshaft timing change is desired. The low reference circuit is used as a return. The CMP actuator solenoid uses electromagnetic force to pull on the plunger of the oil control valve. The oil control valve will port the pressurized engine oil to either the advancing or retarding chambers of the CMP actuator. The CMP actuator changes the camshaft position relative to the crankshaft position. If the ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 12 degrees, DTC P0016, P0017, P0018 P0019 will set.

1. DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095 are not set.
2. The engine is running.
3. The calculated oil temperature is between -10°C to +150°C (+14°F to +302°F).
4. The oil pressure is greater than 105 kPa (15 psi).
5. The Low Oil Switch parameter is 0.
6. The battery voltage is between 11-16 volts.
7. The CMP actuator is commanded to the park position or to its full travel.
8. DTC P0016, P0017, P0018 P0019 runs continuously when the above conditions are met.

The ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 12 degrees for more than 3.6 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)

1. Operate the vehicle at idle and at various engine speeds and load ranges while observing the CMP Variance, Desired CMP, and CMP Angle parameters with a scan tool.
2. All three parameters should remain less than or equal to 1 degree at idle. The CMP Variance should remain less than or equal to 1 degree unless the CMP actuator is being commanded. If the CMP actuator is moved, the CMP Variance will rise for 1-2 seconds until the CMP Angle parameter matches the Desired CMP parameter. The CMP Variance should again return to less than or equal to 1 degree. If the CMP Variance remains more than 1 degree for more than 3 seconds, continue with the Circuit/System Testing.

Repair one of the following conditions with the camshaft timing drive components

1. With the ignition OFF, inspect the engine or review the service history of the vehicle for any recent repairs involving the timing chain, camshaft crankshaft. If recent repairs were made, refer to «Camshaft Timing Drive Chain Alignment Diagram»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction) and inspect the timing chain and sprockets for proper alignment.
2. The supply of clean pressurized engine oil to the CMP actuator is critical to CMP actuator performance. Review the service history of the vehicle for extended intervals between oil changes. Inspect the engine oil for the following: Viscosity breakdown Incorrect viscosity or contains aftermarket additives Low level Debris or other contaminants Mixed with engine coolant Low pressure If the engine oil is old, burnt, contains additives is not the correct viscosity, change the oil and filter. If the engine oil level is low, refer to «Oil Leak Diagnosis»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction__oil-leak-diagnosis) or «Oil Consumption Diagnosis»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction__oil-consumption-diagnosis) to determine the cause for the loss of oil, and repair as necessary. If the engine oil is contaminated or contains debris, determine the cause, and remove the timing chain, CMP actuator, and sprockets. Refer to «Camshaft Cleaning and Inspection»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-3-of-5) . If the engine oil is mixed with coolant, refer to «Coolant in Engine Oil»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction__coolant-in-engine-oil) to determine the cause, and repair as necessary. If the engine oil pressure is low, refer to «Oil Pressure Diagnosis and Testing»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction__oil-pressure-diagnosis-and-testing) to determine the cause, and repair as necessary.
3. Remove the engine front cover, refer to «Engine Front Cover Disassemble»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-4-of-5__engine-front-cover-disassemble-off) and inspect the timing chain, tensioner, and sprockets for proper alignment, wear or damage. Refer to «Camshaft Timing Drive Components Cleaning and Inspection»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-3-of-5) . If any parts are worn or damaged, replace as necessary. If everything else tests normal, replace the CMP actuator.

The use of oil system cleaners and additives is not recommended. Such cleaners contain strong detergents that may adversely react with seals and other engine components.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

DTC P0030, P0036, P0050, P0053, P0054, P0056, P0059, P0060, P0135, P0141, P0155 or P0161

Typical Scan Tool Data

HO2S Heater

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by an ignition voltage circuit through a fuse. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the engine control module (ECM). The ECM uses pulse width modulation (PWM) to control the HO2S heater operation to maintain a specific HO2S operating temperature range.

DTC P0030

The control module monitors the voltage on the HO2S heater low control circuit for heater fault diagnosis. If the control module detects that the HO2S heater low control circuit voltage is not within a specified range, DTC P0030 sets for HO2S 1.

DTC P0053

The control module monitors the resistance on the HO2S heater circuit. If the control module detects that the HO2S heater circuit resistance is not within the calibrated range on a cold start, engine OFF for more than 10 hours, DTC P0053 will set for HO2S 1.

DTC P0135

The control module determines the temperature by measuring the current flow through the heater. For diagnosis, the control module monitors the heater current with the engine running. If the control module detects that the HO2S 1 heater low control circuit current level is not within the calibrated range, DTC P0135 will set for HO2S 1.

DTC P0030, P0036, P0050 P0056

1. The Ignition 1 Signal parameter is between 10-18 volts.
2. The engine speed is more than 400 RPM.
3. The ignition switch is in the Crank or Run position.
4. DTC P0030 and P0036 runs continuously when the above conditions are met for one second.

DTC P0053, P0054, P0059 P0060

1. DTCs P0112, P0113, P0117, P0118, and P2610 are not set.
2. The engine is started.
3. The ignition is OFF for more than 8 hours.
4. The Engine Coolant Temperature (ECT) Sensor parameter is between -30°C and +45°C (-22°F and +113°F) at engine start-up.
5. The ECT Sensor parameter minus the Intake Air Temperature (IAT) Sensor parameter is less than 8°C (14°F) at engine start-up.
6. The ignition voltage is less than 18 volts.
7. DTCs P0053 and P0054 run once per drive cycle when the above conditions are met.

DTC P0135

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The ECT Sensor parameter is more than 60°C (140°F).
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The MAF Sensor parameter is between 5-45 g/s.
5. The Engine Run Time parameter is more than 180 seconds.
6. The Engine Speed parameter is between 500-3,000 RPM.
7. DTC P0135 runs the heater current test twice per drive cycle when the above conditions are met for 2 seconds.

DTC P0141 or P0161

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The ECT Sensor parameter is more than 60°C (140°F).
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The MAF Sensor parameter is between 5-45 g/s.
5. The Engine Run Time parameter is more than 180 seconds.
6. The Engine Speed parameter is between 500-3,000 RPM.
7. DTC P0141 runs the heater current test twice per drive cycle when the above conditions are met for 2 seconds, with a 120-second delay between each test.

DTC P0155

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The ECT Sensor parameter is more than 60°C (140°F).
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The MAF Sensor parameter is between 5-45 g/s.
5. The Engine Run Time parameter is more than 180 seconds.
6. The Engine Speed parameter is between 500-3,000 RPM.
7. DTC P0141 runs the heater current test twice per drive cycle when the above conditions are met for 2 seconds.

DTC P0030, P0036, P0050 P0056

1. The control module detects that the affected HO2S heater low control circuit is not within a specified range.
2. DTCs P0030 and P0036 set when the above condition is met.

DTC P0053, P0054, P0059 P0060

1. The control module detects that the affected HO2S heater low control circuit is not within a specified range at engine start-up.
2. DTCs P0053 and P0054 set within one second when the above condition is met.

DTC P0135

1. The control module detects that the HO2S 1 heater current parameter is more than 3.125 amps or less than 0.25 amps.
2. DTC P0135 sets within 2 seconds during the heater current test when the above condition is met.

DTC P0141 or P0161 Heater Current Test

1. The control module detects that the HO2S 2 heater current parameter is more than 3.125 amps or less than 0.25 amp.
2. These DTCs set within 2 seconds during the heater current test when the above condition is met. Two tests run per trip.

DTC P0155

1. The control module detects that the HO2S 2 heater current parameter is more than 3.125 amps or less than 0.25 amp.
2. DTC P0155 runs the heater current test twice per drive cycle when the above conditions are met for 2 seconds, with a 120-second delay between each test.

This is a Type B DTC.

This is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Schematic Reference

1. «Engine Controls Schematics»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Power Distribution Schematics»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Description and Operation

Engine Control Module Description

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)
5. «Heated Oxygen Sensor Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Scan Tool Data List

1. Allow the engine to reach operating temperature. With the engine running, observe the HO2S Heater parameter with a scan tool. The value should vary from below 2 amp to above 1 amp.
2. With the engine running at operating temperature, observe the HO2S Heater parameter with a scan tool and manipulate the related wiring and connectors. If manipulation does affect the parameter then repair the harness or connector.

1. Ignition OFF, disconnect the harness connector at the appropriate HO2S.
2. Ignition ON, verify that a test lamp illuminates between the appropriate HO2S heater voltage supply circuit terminal D and ground. If the test lamp does not illuminate, test the HO2S heater voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the HO2S heater voltage supply circuit fuse is open, test all components connected to the fuse and replace as necessary.
3. Ignition ON, verify that a test lamp does not illuminate between the appropriate HO2S heater low control circuit and the HO2S heater voltage supply circuit terminal D. B1S1 and B2S1 terminal E B1S2 and B2S2 terminal C If the lamp illuminates, test the HO2S heater low control circuit for a short to ground. If the circuit tests normal, replace the ECM.
4. Engine running, leave the test lamp connected from the previous step. The lamp should flash or be ON steady. If the test lamp is not on steady or flashing, test the HO2S heater low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. Ignition OFF, install a 30-amp fused jumper wire between the appropriate HO2S heater low control circuit and the HO2S heater voltage supply circuit terminal D. B1S1 and B2S1 terminal E B1S2 and B2S2 terminal C
6. Engine running, verify the appropriate scan tool Heater parameter is less than 0.1 amp. If more than the specified range, test the HO2S heater voltage supply and HO2S heater low control circuits for more than 1 ohm of resistance. If the circuits test normal, replace the ECM.
7. If the ECM and all circuits test normal, replace the appropriate HO2S.

Note. Refer to Heated Oxygen Sensor Resistance Learn Reset Notice .

1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
4. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
5. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Supercharger Vacuum Bypass Valve Control Solenoid

Supercharger boost pressure is regulated to prevent engine and drive train damage. When the engine is operating under high boost conditions, the engine control module (ECM) limits boost pressure to 12 psi or less. The ECM disables boost under the following conditions

1. When reverse gear is selected
2. When an electronic throttle control (ETC) fault is detected.
3. When an intercooler pump failure is detected
4. When the intake air temperature (IAT) sensor 2 becomes excessively high, equal to or greater than 120.5°C (248°F) boost pressure is limited to 145 kPa (7 psi). ECM commands the boost control solenoid to 62 percent duty cycle (DC).
5. When the engine coolant temperature (ECT), is equal to or greater than 125°C (257°F) the HOT engine light comes on.
6. When drivetrain abuse is detected
7. When vehicle speeds exceed 256 km/h (159 mph) in third and fourth gears, after 150 seconds boost is limited to a predetermined threshold.
8. When the intake cam phasers are inoperable, boost pressure is limited to 145 kPa (7 psi), ECM commands the boost control solenoid to 62 percent duty cycle.

The ECM controls boost pressure by pulse width modulation (PWM) of the boost control solenoid. The boost control solenoid is a normally open valve. Under most conditions, the ECM commands the boost control solenoid to operate at a 99-100 percent duty cycle. This keeps the boost control solenoid valve closed and allows only inlet vacuum from the supercharger plenum to the bypass valve actuator to control the position of the bypass valve. At idle, engine vacuum is applied to the upper side of the bypass valve actuator, counteracting spring tension to hold the bypass valve open. When the engine load is increased, the engine vacuum is decreased, causing the spring in the bypass valve actuator to overcome the diminishing applied vacuum, closing the bypass valve and allowing the boost pressure to increase. When reduced boost pressure is desired, the ECM commands the boost control solenoid to operate at a 0-98 percent duty cycle. This opens the solenoid valve and allows boost pressure to enter the bypass valve actuator at the lower side to counteract the spring tension, opening the bypass valve and recirculating excess boost pressure back into the supercharger inlet.

The ECM monitors the voltage level on the boost control solenoid control circuit. Refer to Boost Control System Description for further information.

1. The ignition is ON. OR
2. The engine is running.
3. The ignition 1 voltage is between 11-18 volts.
4. This DTC runs continuously within the enabling conditions.

The ECM detects an improper voltage level on the boost control solenoid control circuit for more than 20 seconds.

DTC P0033 is a Type B DTC.

DTC P0033 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)
5. «Measuring Frequency»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__measuring-frequency)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Engine running, command the supercharger vacuum bypass valve control (SCB) solenoid, duty cycle from 0 percent to 90 percent in 10 percent increments with a scan tool. Listen and feel for a clicking at the supercharger SCB solenoid.
2. Engine running, observe the scan tool SCB Solenoid Circuit Status parameter. The reading should change from incomplete to OK when commanding the SCB solenoid.
3. Engine running, observe the DTC information with a scan tool. DTC P0033 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the SCB solenoid.
2. Ignition ON, verify that a test lamp illuminates between the ignition supply circuit and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
3. Connect a test lamp between the control circuit and the ignition supply circuit.
4. Engine running, command the SCB solenoid duty cycle from 0 percent to 90 percent with a scan tool. The test lamp should change brightness when incrementing between the commanded states. If the test lamp remains ON all the time, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. If the test lamp remains OFF all the time, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test the SCB solenoid. Refer to Component Testing for instructions.

Static Test

1. Ignition OFF, disconnect the harness connector at the SCB solenoid.
2. Test for 30-55 ohms of resistance between the control terminal and the voltage supply terminal of the SCB solenoid. If the resistance is not within the specified range, replace the SCB solenoid.

Dynamic Test

1. Install a 3A fused jumper wire between the ignition supply circuit terminal and 12 volts. Install a jumper wire between the control terminal and ground.
2. Toggle the jumper wire between the control terminal and ground.
3. Feel and listen for the operation of the SCB solenoid. If the function does not perform as specified, replace the SCB solenoid.

1. «Supercharger Bypass Regulator Solenoid Valve Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Repair Verification

Engine running, command the supercharger vacuum SCB solenoid duty cycle from 0 percent to 100 percent in 10 percent increments with a scan tool. Listen and feel for the SCB solenoid to click.

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The actual throttle position and airflow rate is compared to an expected throttle position and airflow rate based on engine load. The engine control module (ECM) determines engine load based on inputs from the mass air flow (MAF) sensor and the manifold absolute pressure (MAP) sensor. Further comparisons are done to distinguish if a sensor is at fault, and the respective DTC will set.

The ECM uses the following information to calculate an expected airflow rate

1. The throttle position (TP)
2. The barometric pressure (BARO)
3. The MAP
4. The supercharger inlet pressure (SCIP)
5. The intake air temperature (IAT)
6. The engine RPM

P0068

1. DTCs P0122, P0123, P0220, P0221, P0222, P0223, P0601, P0602, P0603, P0604, P0606, P0607, P060D, P062F, P0641, P0651, P1516, P2101, P2119, P2135, P2176, P2610 are not set.
2. The engine is running.
3. DTC P0068 runs continuously when the above conditions are met.

P0121

1. DTCs P0096, P0097, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0116, P0128, P0122, P0123, P0220, P0221, P0222, P0223, P0335, P0336, P0401, P0405, P0601, P0602, P0603, P0604, P0606, P0607, P060D, P062F, P0641, P0651, P1182, P1183, P1184, P1404, P1516, P2101, P2119, P2135, P2176, P2610 are not set.
2. The engine coolant temperature (ECT) is between 70-121°C (158-249°F).
3. The engine IAT is between -7° and +60°C (+19° and +140°F).
4. The engine speed is between 550-5,000 RPM.
5. DTC P0121 runs continuously when the above conditions are met.

The ECM detects that the airflow rate is more than the calculated airflow for more than 0.2 second.

Action Taken When DTC

1. DTC P0068 is a Type A DTC.
2. DTC P0121 is a Type B DTC.

1. DTC P0068 is a Type A DTC.
2. DTC P0121 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. If DTCs P0101, P0106, P0120, P0220, and P1182 are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) for further diagnosis.
2. Ignition ON, observe the scan tool BARO, MAP, and the SC Inlet Pressure sensor parameters. The readings should be within the range specified for your altitude. Determine the altitude at your current location and refer to «Altitude Versus Barometric Pressure»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__altitude-versus-barometric-pressure) .

1. Start the engine. The Manifold Absolute Pressure (MAP) and SC Inlet Pressure Sensor parameters should decrease and closely match each other. If the MAP sensor parameter does not decrease, refer to «DTC P0106»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) . If the SC Inlet Pressure sensor parameter does not decrease, refer to «DTC P1182»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0506-to-p2544) .
2. Engine running, inspect for any of the following conditions: Vacuum hoses for splits, leaks, and proper connections Air leaks at throttle body mounting area and intake manifold sealing surfaces A supercharger bypass valve that is binding or incorrectly adjusted If any of the above conditions are found, repair as necessary.
3. While taking a snapshot of the engine data list, perform the following actions. Idle the engine. Increase the engine speed slowly to 3,000 RPM, then return to an idle. Observe the Mass Air flow (MAF) Sensor parameter frame by frame with a scan tool. The MAF sensor parameter should change smoothly as the engine speed is increased and is returned to idle. If the MAF sensor parameter does not change smoothly as the engine speed is increased and is returned to idle, refer to «DTC P0101»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
4. Engine running, slowly depress the accelerator pedal to a WOT position, then slowly release the pedal while comparing the TP Sensor 1 and TP Sensor 2 parameters. The difference between the parameters should be less than 4 percent. If the voltage is 4.8-5.2 volts, then proceed to the next numbered step. If TP Sensor 1 and TP Sensor 2 parameters differ more than 4 percent, refer to «DTC P0120, P0122, P0123, P0220, P0222, P0223 P2135»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
5. Ignition OFF, inspect the throttle body for the following conditions: Loose or damaged throttle blade Broken throttle shaft Any throttle body damage If any of these conditions exist, replace the throttle body assembly.

1. «Throttle Body Assembly Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

SC Inlet Pressure Sensor

BARO Sensor

SC Inlet Pressure Sensor

BARO Sensor

The barometric pressure (BARO) sensor measures the pressure of the atmosphere. This pressure is affected by altitude and weather conditions. A diaphragm within the BARO sensor is displaced by the pressure changes that occur from varying altitudes and weather conditions. The sensor translates this diaphragm action into the voltage signal input that is used by the engine control module (ECM) for diagnostics and emissions control.

The supercharger inlet absolute pressure (SCIP) sensor measures the absolute pressure of the air just after the throttle body, at the inlet of the supercharger. The plenum volume between the throttle body (TB) and the supercharger is where this sensor is located, and for the purpose of this diagnostic, this area is considered to be the intake manifold. The diaphragm within the SCIP sensor functions in the same manner as the BARO sensor. The sensors are not interchangeable.

The purpose of this diagnostic is to analyze the correlation between the BARO sensor, and the SCIP sensor. This is accomplished by continually comparing the difference between BARO and SCIP at key ON, engine OFF (KOEO), at closed throttle idle conditions, and at wide open throttle update events. At KOEO the difference between BARO and SCIP is represented on the scan tool by the SC Inlet Pressure parameter as a value that should be very close to zero. A negative SC Inlet Pressure parameter means that the BARO sensor value is less than the SCIP value. A positive SC Inlet Pressure parameter represents a BARO sensor value that is more than the SCIP value.

At idle the SC Inlet Pressure parameter represents the calculated difference between BARO and the reduced pressure that is present in the supercharger intake plenum as a positive value. At wide open throttle the SC Inlet Pressure parameter represents the calculated difference between BARO and the increased pressure that is present in the supercharger intake plenum, and should be very close to zero.

Both sensors have the following types of circuits

1. A ECM supplied and regulated 5-volt reference circuit
2. A ECM supplied ground for the low reference circuit
3. A sensor signal circuit that supplies a voltage input to the ECM

Changes in BARO due to weather are relatively small, while changes due to altitude are significant. Pressure can range from 56 kPa at an altitude of 4267 meters (14,000 feet), to 104 kPa at or below sea level.

If the ECM detects that the BARO sensor signal and the SCIP sensor signal are not within a calibrated range of each other, whether that value is negative or positive, DTC P0069 sets.

1. DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0128, P0220, P0502, P1182, P1183, P1184, P1516, P2101, P2227, P2228, P2229 are not set.
2. The ignition is ON. OR
3. The engine is running.
4. DTC P0069 runs continuously when the above conditions are met.

1. The ECM detects that during ignition ON, with the engine OFF, the calculated difference between BARO and SCIP, whether that value is negative or positive, is more than 12 kPa for more than 30 seconds. OR
2. The ECM has detected that a wide open throttle update event has occurred within the previous 2 kilometers (1.2 miles) and the difference between BARO, and a calculated BARO using the SCIP sensor, is more than 12 kPa for more than 30 seconds. OR
3. The ECM has not detected a wide open throttle update event within the previous 2 kilometers (1.2 miles) and the difference between BARO, and a calculated BARO using the SCIP sensor, is more than 60 kPa for more than 30 seconds.

DTC P0069 is a Type B DTC.

DTC P0069 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Component Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

Special Tools Required

J 35555 Metal Mityvac. See Special Tools .

1. Verify that DTCs P0106, P0107, P0108, P0641, P0651, P1182, P1183, P1184 P2227, P2228, P2229 are not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) .
2. Ignition ON, engine OFF, observe the scan tool SC Inlet Pressure and BARO parameters. Verify the SC Inlet Pressure and BARO sensor parameters are within 5 kPa of each other.
3. Ignition ON, observe the scan tool SC Inlet Pressure Sensor parameter. Start the engine, the SC Inlet Pressure Sensor parameter should decrease.
4. Verify the integrity of the SCIP and BARO sensors by inspecting for the following conditions: Damaged components Loose or improper installation An air flow restriction A cracked or restricted SCIP sensor vacuum hose An intake manifold leak

1. Determine the altitude for your area. Refer to «Altitude Versus Barometric Pressure»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__altitude-versus-barometric-pressure) .
2. Ignition ON, determine which sensor is out of range by comparing SC Inlet Pressure and BARO Sensor parameters with a scan tool. Both sensor values should be within 5 kPa of each other and the Altitude vs. Barometric Pressure table.
3. Ignition OFF, disconnect the harness connector at the affected sensor.
4. Ignition OFF, allow sufficient time for the control module to power down. Test for less than 5 ohms of resistance between the low reference circuit terminal and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
5. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
6. Verify the scan tool sensor parameter is less than 12 kPa. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
7. Install a 3A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool sensor parameter is greater than 250 kPa. If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
8. If all circuits test normal, test or replace the affected sensor.

Component Test

1. Turn ON the ignition with the engine OFF, and remove the affected sensor.
2. Install a 3A fused jumper wire between the 5-volt reference terminal of the sensor and 5-volt reference.
3. Install a jumper wire between the low reference terminal of the sensor and ground.
4. Install a jumper wire at the signal terminal sensor.
5. Connect a DMM between the jumper wire from terminal of the sensor and ground.
6. Install the J 35555 to the sensor vacuum port. See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__special-tools) . Slowly apply vacuum to the sensor while monitoring the voltage on the DMM. The voltage should vary between 0-5.2 volts, without any spikes or dropouts. If the voltage is not within the specified range or is erratic, replace the affected sensor.

1. «Supercharger Inlet Absolute Pressure Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Barometric Pressure Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Ignition ON, observe the scan tool MAP, SC Inlet Pressure, and BARO sensor parameters. The MAP, SC Inlet Pressure, and BARO sensor parameters should be within 5 kPa of each other.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

IAT Sensor 2

IAT Sensor

IAT Sensor 2

IAT Sensor

The intake air temperature (IAT) sensor 2 is a variable resistor. The IAT sensor 2 measures the temperature of the air at the engine intake manifold. The engine control module (ECM) supplies 5 volts to the IAT sensor 2 signal circuit, and a ground for the IAT sensor 2 low reference circuit. When the IAT sensor 2 is cold, the sensor resistance is high. When the intake manifold air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT sensor 2 signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT sensor 2 signal circuit. The ECM monitors the IAT sensor 2 and the IAT sensor signal voltages for a voltage that is not within a calibrated range of each other.

1. DTCs P0097, P0098, P0112, P0113, P0116, P0117, P0118, P0128, P0500, P0502, P0603 are not set.
2. DTC P0116 has run and passed.
3. The engine has been OFF for more than 8 hours.
4. The IAT sensor is more than 10°C (50°F).
5. DTC P0096 runs once per key cycle within the enabling conditions.

1. DTC P0116 must run and pass.
2. At start-up, after an 8 hour engine soak time, the IAT sensor 2 temperature is more than 20°C (36°F) higher or lower than the IAT sensor.

DTC P0096 is a Type B DTC.

DTC P0096 is a Type B DTC.

Diagnostic Aids

1. An IAT sensor that is skewed lower at various ambient temperatures, due to more resistance than is normal, can widen the spread between the 2 sensors and cause this DTC to set. Measure and record the resistance of the IAT sensor and IAT sensor 2 at various ambient temperatures, and then compare those measurements to the Temperature vs. Resistance Table. Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) .
2. Inspect both IAT sensors terminals, for corrosion or a poor connection.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Engine Controls Component Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. If DTC P0112, P0113, P0097 P0098 are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) .
2. Ignition ON, observe the scan tool IAT sensor, the IAT sensor 2, and the ECT sensor parameters. The readings should be within 15°C (27°F) of each other, and also the ambient temperature.
3. Engine running, observe the DTC information with a scan tool. DTC P0096 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor and the IAT sensor 2.
2. Ignition OFF, allow sufficient time for the control module to power down. Test for less than 5 ohms of resistance between the IAT sensor low reference circuit terminal D and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition OFF, allow sufficient time for the control module to power down. Test for less than 5 ohms of resistance between the IAT sensor 2 low reference circuit terminal B and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
4. Ignition OFF, disconnect the harness connector at the ECM.
5. Test for less than 5 ohms of resistance between the signal circuit terminal of the IAT sensor and the corresponding terminal E of the ECM. If greater than the specified range, repair the open/high resistance in the circuit.
6. Test for less than 5 ohms of resistance between the signal circuit terminal of the IAT sensor 2 and the corresponding terminal of the ECM. If greater than the specified range, repair the open/high resistance in the circuit.
7. If all circuits test normal, test the affected sensor. Refer to Component Testing.

1. Compare the resistance of the IAT sensor 2 sensor to the temperature vs resistance table. If the difference is more than 9 percent, replace the IAT sensor 2.
2. Compare the resistance of the IAT sensor to the temperature vs resistance. If the difference is more than 9 percent, replace the MAF/IAT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Intake Air Temperature (IAT) Sensor 2 Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Mass Airflow Sensor/Intake Air Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0097 or P0098

IAT Sensor 2

The intake air temperature (IAT) sensor 2 is a variable resistor. The IAT sensor 2 has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air at the engines intake manifold. The engine control module (ECM) supplies 5 volts to the IAT 2 signal circuit, and a ground for the IAT 2 low reference circuit. When the IAT sensor 2 is cold, the sensor resistance is high. When the intake manifold air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT 2 signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT 2 signal circuit. The ECM continuously monitors the IAT signal voltage for an excessively high or low voltage a voltage signal that is not in correlation with the mass air flow (MAF)/IAT sensor.

Conditions for Running

1. The engine run has been in operation for greater than 10 seconds.
2. The engine coolant temperature (ECT) is less than 150°C (302°F).
3. The vehicle speed is greater than 1 km/h (1 mph).
4. The MAF is less than 512 g/s.
5. DTC P0097 and P0098 run continuously within the enabling conditions

P0097

The IAT sensor 2 is more than 148°C (298°F) for more than 1 second. This is equal to or less than 0.24 volt on the IAT sensor 2 signal circuit as measured by the ECM for P0097.

P0098

The IAT sensor 2 is less than -39°C (-38°F) for more than 1 second. This is equal to or more than 4.86 volts on the IAT signal circuit as measured by the ECM for P0098.

DTCs P0097 and P0098 are Type B DTCs.

DTCs P0097 and P0098 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Definitions

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2, and ECT Sensor parameters. The readings should be within 15°C (27°F) of each other, and also the ambient temperature.
2. Engine running, observe the DTC information with a scan tool. DTCs P0097 or P0098 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the IAT sensor 2.
2. Ignition OFF, allow sufficient time for the control module to power down. Test for less than 5 ohms of resistance between the low reference circuit terminal B and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool IAT sensor 2 parameter is less than -39 (-38°F). If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3 amp fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool IAT sensor 2 parameter is greater than 130°C (266°F). If less than the specified range, test the signal circuit terminal A for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test the IAT sensor 2. Refer to Component Testing for instructions.

Compare the IAT sensor 2 resistance to the values listed in the Temperature vs. Resistance table. Refer to Temperature Versus Resistance .

1. If the resistance is not within the range listed in the temperature vs. resistance table, replace the IAT sensor 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Intake Air Temperature (IAT) Sensor 2 Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

DTC P0101

MAF Sensor

The intake airflow system performance diagnostic provides the within-range rationality check for the mass air flow (MAF), supercharger inlet absolute pressure (SCIP), MAP, by-pass valve stuck, and the throttle position (TP) sensors. This is an explicit model-based diagnostic containing 4 separate models for the intake system.

1. The throttle model describes the flow through the throttle body and is used to estimate the MAF through the throttle body as a function of barometric pressure (BARO), throttle position, intake air temperature (IAT), and estimated SCIP. The information from this model is displayed on the scan tool as the MAF Performance Test parameter.
2. The first supercharger intake manifold model describes the pressure at the supercharger intake manifold and is used to estimate SCIP as a function of the MAF into the intake manifold from the throttle body and the MAF out of the intake manifold caused by engine pumping. The flow into the supercharger intake manifold from the throttle uses the MAF estimate calculated from the above throttle model. The information from this model is displayed on the scan tool as the MAP Performance Test 1 parameter.
3. The second supercharger intake manifold model is identical to the first supercharger intake manifold model except that the MAF sensor measurement is used instead of the throttle model estimate for the throttle air input. The information from this model is displayed on the scan tool as the MAP Performance Test 2 parameter.
4. A fourth model is created from the combination and additional calculations of the throttle model and the first supercharger intake manifold model. The information from this model is displayed on the scan tool as the TP Performance Test parameter.
5. In addition 5 new models have been added, these models run in the background.

The estimates of MAF, SCIP, and TP that are obtained from this system of models and calculations are then compared to the actual measured values from the MAF, SCIP, and the TP sensors and to each other to determine the appropriate DTC to fail. The following table illustrates the possible failure combinations and the resulting DTC or DTCs.

DTC P0101

1. DTCs P0096, P0097, P0098, P0102, P0103, P0107, P0108, P0111, P0112, P0113, P0116, P0117, P0118, P0335, P0336, P1183, P1184, P2226, P2227, P2228 are not set.
2. The engine speed is between 500-5,000 RPM.
3. The IAT Sensor parameter is between -7 and +125°C (+19 and +257°F).
4. The engine coolant temperature (ECT) Sensor parameter is between 70-121°C (158-250°F).
5. This DTC runs continuously within the enabling conditions.

The engine control module (ECM) detects that the actual measured airflow from the MAF, the MAP, SCIP, and the TP sensors is not within range of the calculated airflow that is derived from the system of models for more than 0.5 second.

DTC P0101 is a Type B DTC.

DTC P0101 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

Special Tools Required

1. J 38522 Variable Signal Generator. See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__special-tools) .
2. J 35616-200 Test Light - Probe Kit

1. Any condition that can cause the MAF, MAP, SCIP, and TP sensors to be shifted in value or any condition that may cause the by-pass valve to stick, at the same time may cause this DTC to set.
2. A slight to moderate resistance of 10-20 ohms on the ignition or ground circuits may cause this DTC to set.
3. Road test the vehicle and verify that the MAF sensor calculated g/s and the actual MAF g/s parameters are near or equal to each other.
4. A skewed MAF sensor, intake air flow restriction or intake air flow leak after the MAF sensor may cause the calculated g/s and MAF g/s parameters to disagree. Road test the vehicle while observing both parameters under various engine loads.
5. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 6-10 g/s at idle to 380 g/s or more at the time of the 2-3 shift.
6. A steady or intermittent high resistance of 15 ohms or more on the ignition 1 voltage circuit will cause the MAF sensor values to be skewed high by up to 60 g/s.
7. A skewed or stuck ECT or IAT sensor 1 will cause the calculated models to be inaccurate and may cause this DTC to run when it should not. Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) .

1. Verify the integrity of the air induction system by inspecting for the following conditions: A bypass valve that is binding or incorrectly adjusted A restricted or collapsed air intake duct A misaligned or damaged air intake duct A dirty or deteriorating air filter element Any objects blocking the air inlet probe of the MAF/IAT sensor Any contamination or debris on the sensing elements in the probe of the MAF/IAT sensor Any water intrusion in the induction system Any vacuum leak downstream of the MAF/IAT sensor An intake manifold leak A SCIP sensor vacuum hose that is missing or damaged A MAP sensor vacuum hose that is missing or damaged A BARO sensor that is skewed or stuck A skewed or stuck ECT or IAT sensor-Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) . Any type of restriction in the exhaust system-Refer to «Restricted Exhaust»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
2. Ignition ON, observe the MAP and SC Inlet Pressure Sensor kPa parameters with a scan tool. Start the engine. The MAP and SC Inlet Pressure Sensor kPa parameters should decrease. If the MAP Sensor kPa parameter does not decrease, refer to «DTC P0106»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) . If the SC Inlet Pressure kPa parameter does not decrease, refer to «DTC P1182»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0506-to-p2544) .
3. Ignition ON, depress the accelerator pedal completely and observe the TP Indicated Angle parameter with a scan tool. The TP Indicated Angle parameter should read 98-100 percent. If the TP Indicated Angle parameter is not within the specified range, refer to «DTC P1516, P2101, P2119 P2176»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0506-to-p2544) .
4. With the ignition ON and the engine OFF, perform a snapshot of the throttle actuator control (TAC) data while performing the following action. Refer to «Scan Tool Snapshot Procedure»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) . Slowly depress the accelerator pedal to WOT position and then slowly release the pedal. Exit from the snapshot and review the data. Compare the TP Sensor 1 and the TP Sensor 2 parameters, frame by frame. The difference between the parameters should be less than 4 percent. If the TP Sensor 1 and Sensor 2 parameter difference is more than 4 percent, refer to «DTC P0120, P0122, P0123, P0220, P0222, P0223 P2135»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .

1. Ignition OFF, disconnect the harness connector at the MAF sensor.
2. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the MAF sensor signal circuit terminal A and ground. If less than the specified range, test the MAF sensor signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module. If greater than the specified range, test the MAF sensor signal circuit for a short to voltage. If the circuit tests normal, replace the control module.
4. Ignition ON, verify that a test lamp illuminates between the MAF sensor ignition 1 voltage circuit terminal C and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
5. Connect the J 38522 to the vehicle. See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__special-tools) . Refer to Component Testing.

To determine if the ECM can properly process the MAF sensor frequency signal, connect the J 38522 to the vehicle as follows. See Special Tools .

1. Turn OFF the ignition.
2. Connect the battery voltage supply and ground the black lead.
3. Connect the red lead to the signal circuit of the MAF sensor.
4. Set the duty cycle switch to Normal.
5. Set the Frequency switch to 5 K.
6. Set the signal switch to 5 volts.
7. Start the engine, observe the MAF Sensor parameter for the correct range of 4,950-5,025 Hz. If the MAF Sensor parameter is not within the specified range, replace the ECM. If the MAF Sensor parameter is within the specified range, replace the MAF sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Mass Airflow Sensor/Intake Air Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0102 or P0103

MAF Sensor

The mass air flow (MAF) sensor is integrated with the intake air temperature (IAT) sensor. The MAF sensor is an air flow meter that measures the amount of air entering the engine. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF/IAT sensor has the following circuits

1. An ignition 1 voltage circuit
2. A ground circuit
3. A MAF sensor signal circuit
4. An IAT sensor signal circuit
5. A low reference circuit

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,000 Hertz at idle to near 9,500 Hertz at maximum engine load.

1. The engine is running for more than 1 second.
2. The engine speed is more than 300 RPM.
3. The ignition 1 signal is more than 8 volts.
4. The above conditions are met for more than 1 second.
5. This DTC runs continuously within the enabling conditions.

P0102

The ECM detects that the MAF Sensor parameter is less than 10 Hz for more than 5 seconds.

P0103

The ECM detects that the MAF Sensor parameter is more than 14,500 Hz for more than 5 seconds.

DTC P0102 and P0103 are Type B DTCs.

DTC P0102 and P0103 are Type B DTCs.

1. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 6-10 g/s at idle to 380 g/s or more at the time of the 1-2 shift.
2. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to «Checking Aftermarket Accessories»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__checking-aftermarket-accessories) .

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

Special Tools Required

1. J 38522 Variable Signal Generator. See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__special-tools) .
2. J 35616-200 Test Light - Probe Kit

1. Verify the integrity of the air induction system by inspecting for the following conditions: Damaged components Loose or improper installation An air flow restriction Any vacuum leak Water intrusion
2. Engine running, observe the DTC information with a scan tool. DTCs P0102 or P0103 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
2. Ignition OFF, test for less than 2 ohms of resistance between the MAF ground circuit and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the MAF signal circuit and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Ignition ON, verify a test lamp illuminates between the ignition circuit and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
5. Connect the J 38522 to the vehicle. See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__special-tools) . Refer to Component Testing.

To determine if the ECM can properly process the MAF sensor frequency signal, connect the J 38522 to the vehicle as follows. See Special Tools .

1. Turn OFF the ignition.
2. Connect the battery voltage supply, and ground the black lead.
3. Connect the red lead to the signal circuit of the MAF sensor.
4. Set the Duty Cycle switch to Normal.
5. Set the Frequency switch to 5 K.
6. Set the Signal switch to 5 V.
7. Start the engine and observe the MAF Sensor parameter for the correct range of 4,950-5,025 Hz. If the MAF Sensor parameter is not within the specified range, replace the ECM. If the MAF Sensor parameter is within the specified range, replace the MAF sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Mass Airflow Sensor/Intake Air Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

DTC P0106

MAP Sensor

The intake airflow system performance diagnostic provides the within-range rationality check for the mass air flow (MAF), supercharger inlet absolute pressure (SCIP), MAP, by-pass valve stuck, and the throttle position (TP) sensors. This is an explicit model-based diagnostic containing 4 separate models for the intake system.

1. The throttle model describes the flow through the throttle body and is used to estimate the MAF through the throttle body as a function of barometric pressure (BARO), throttle position, intake air temperature (IAT), and estimated SCIP. The information from this model is displayed on the scan tool as the MAF Performance Test parameter.
2. The first supercharger intake manifold model describes the pressure at the supercharger intake manifold and is used to estimate SCIP as a function of the MAF into the intake manifold from the throttle body and the MAF out of the intake manifold caused by engine pumping. The flow into the supercharger intake manifold from the throttle uses the MAF estimate calculated from the above throttle model. The information from this model is displayed on the scan tool as the MAP Performance Test 1 parameter.
3. The second supercharger intake manifold model is identical to the first supercharger intake manifold model except that the MAF sensor measurement is used instead of the throttle model estimate for the throttle air input. The information from this model is displayed on the scan tool as the MAP Performance Test 2 parameter.
4. A fourth model is created from the combination and additional calculations of the throttle model and the first supercharger intake manifold model. The information from this model is displayed on the scan tool as the TP Performance Test parameter.
5. In addition 5 new models have been added, these models run in the background.

The estimates of MAF, SCIP, and TP that are obtained from this system of models and calculations are then compared to the actual measured values from the MAF, SCIP, and the TP sensors and to each other to determine the appropriate DTC to fail. The following table illustrates the possible failure combinations and the resulting DTC or DTCs.

DTC P0106

1. DTCs P0069, P0107, P0108, P0120, P0121, P0220, P0506, P0507, P1183, P1184, P2135, P2228 P2229 are not set.
2. The engine speed is less than 900 RPM.
3. This DTC runs continuously within the enabling conditions.

1. The ECM detects that the MAP sensor signal is 25 kPa more than the calibrated estimate for more than 90 seconds. OR
2. The ECM detects that the MAP sensor signal is 45 kPa less than the calibrated estimate for more than 90 seconds.

DTC P0106 is a Type A DTC.

DTC P0106 is a Type A DTC.

1. Any condition that can cause the MAF, MAP, SC inlet pressure, and TP sensors to be shifted in value or any condition that may cause the by-pass valve to stick, at the same time may cause this DTC to set.
2. A slight to moderate resistance of 10-20 ohms on the ignition or ground circuits may cause this DTC to set.
3. Road test the vehicle and verify that the MAF sensor calculated g/s and the actual MAF g/s parameters are near or equal to each other.
4. A skewed MAF sensor, intake air flow restriction or intake air flow leak after the MAF sensor may cause the calculated g/s and MAF g/s parameters to disagree. Road test the vehicle while observing both parameters under various engine loads.
5. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 6-10 g/s at idle to 380 g/s or more at the time of the 2-3 shift.
6. A steady or intermittent high resistance of 15 ohms or more on the ignition 1 voltage circuit will cause the MAF sensor values to be skewed high by up to 60 g/s.
7. A skewed or stuck ECT or IAT sensor 1 will cause the calculated models to be inaccurate and may cause this DTC to run when it should not. Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) .
8. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to «Checking Aftermarket Accessories»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__checking-aftermarket-accessories) .

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Component Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

Special Tools Required

J 35555 Metal Mityvac. See Special Tools .

1. If DTCs P0069, P0107, P0108 are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) for further information.
2. Ignition ON, observe the scan tool MAP, SC Inlet Pressure, and BARO parameters. Verify the MAP, SC Inlet Pressure, and BARO sensor parameters are within 5 kPa of each other.
3. Ignition ON, observe the MAP Sensor kPa parameter with a scan tool. Start the engine. The MAP Sensor kPa parameter should decrease.
4. Engine running at idle, observe and record the MAP Sensor parameter kPa value with a scan tool. Slowly increase the engine speed from idle to 2,000 RPM, then allow the engine speed to return idle. The MAP sensor parameter should increment to a higher value at 2,000 RPM and return to the recorded idle value.
5. Verify the integrity of the air induction system by inspecting for the following conditions: Damaged components Loose or improper installation An air flow restriction A cracked or restricted MAP sensor vacuum hose An intake manifold leak
6. Ignition ON, compare APP sensors 1 and 2 percentages with a scan tool. Verify that they do not differ more than 5 percent when a slow pedal sweep is performed.

1. Ignition OFF, disconnect the harness connector at the MAP sensor.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal and ground. If greater than the specified range, test the low reference circuit for an open or high resistance. If the circuit tests normal, replace the control module.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground, open high resistance. If the circuit tests normal, replace the control module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the control module.
4. Verify the scan tool MAP Sensor parameter is less than 0.2 volt. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the control module.
5. Install a 3A fused jumper wire between the signal circuit terminal and the 5-volt reference terminal. Verify the scan tool MAP Sensor parameter is greater than 200 kPa. If less than the specified range, test the signal circuit for a short to ground, open high resistance. If the circuit tests normal, replace the control module.
6. If all circuits test normal, test the MAP sensor. Refer to Component Testing

1. Ignition OFF, remove the MAP sensor.
2. Install a 3A fused jumper wire between the 5-volt reference terminal of the sensor and 5 volts.
3. Install a jumper wire between the low reference terminal of the sensor and ground.
4. Ignition ON, install the J 35555 to the MAP sensor vacuum fitting. See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__special-tools) . Slowly apply vacuum to the sensor while monitoring the voltage between the signal terminal and the low reference terminal. the voltage should vary between 5-0 volts, without any spikes or dropouts. If the voltage is not within the specified range or is erratic, replace the MAP sensor.

1. «Manifold Absolute Pressure Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Ignition ON, observe the MAP, SC Inlet Pressure, and BARO parameters with a scan tool. The MAP, SC Inlet Pressure, and BARO sensor parameters should be within 5 kPa of each other.
2. With a scan tool, command the supercharger bypass control valve ON. Slowly increase the engine speed from idle to 2,000 RPM and return the engine to idle speed. The MAP sensor parameter should increment to a higher value and return to the normal idle value.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0107 or P0108

MAP Sensor

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature, and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is ON while the engine is OFF. Under these conditions, the ECM uses the MAP sensor to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 8-10 kPa, when pressures are low, to as much as 207 kPa when pressures are high, depending on the BARO. The ECM monitors the MAP sensor signal for pressure outside of the normal range.

P0107

1. DTCs P0120, P0121, P0122, P0123, P0220, P0221, P0222, P0223, P0641 P0651 are not set.
2. The throttle angle is more than 0 percent when the engine speed is less than 800 RPM. OR
3. The throttle angle is more than 12 percent when the engine speed is more than 800 RPM.
4. This DTC runs continuously within the enabling conditions.

P0108

1. DTCs P0120, P0121, P0122, P0123, P0220, P0221, P0222, P0223, P0641 P0651 are not set.
2. The engine has been running for a period of time that is determined by the start-up engine coolant temperature (ECT). The time ranges from 4 minutes at less than -30°C (-22°F) to 2 seconds at more than +30°C (+86°F).
3. The throttle angle is less than 1 percent when the engine speed is less than 1,200 RPM. OR
4. The throttle angle is less than 20 percent when the engine speed is more than 1,200 RPM.
5. This DTC runs continuously within the enabling conditions.

P0107

The ECM detects that the MAP sensor voltage is less than 0.10 volt for more than 5 seconds.

P0108

The ECM detects that the MAP sensor voltage is more than 4.80 volts for more than 5 seconds.

DTCs P0107 and P0108 are Type B DTCs.

DTCs P0107 and P0108 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

Special Tools Required

J 35555 Metal Mityvac. See Special Tools .

1. Verify the integrity of the MAP sensor system by inspecting for the following conditions: Any damage to the MAP sensor housing Any damage to the MAP sensor seal A loose or improperly installed MAP sensor A restriction in the vacuum source of the MAP sensor
2. Ignition ON, observe the scan tool MAP, SC Inlet Pressure, and BARO sensor parameters. The readings should be within 5 kPa of each other and also the current BARO for your location. Refer to «Altitude Versus Barometric Pressure»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__altitude-versus-barometric-pressure) .
3. Engine running, observe the DTC information with a scan tool. DTCs P0107 or P0108 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the MAP sensor.
2. Ignition OFF, allow sufficient time for the control module to power down. Measure for less than 5 ohms of resistance between the low reference circuit of the connector and a good ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground. If less than the specified range, test the 5-volt reference circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Verify the scan tool MAP sensor voltage parameter is less than 13 kPa. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
5. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit. Verify the scan tool MAP sensor parameter is greater than 253 kPa. If less than the specified range, test the sensor signal circuit for high resistance.
6. If all circuits test normal, test the MAP sensor. Refer to Component Test.

1. Ignition OFF, remove the MAP sensor.
2. Install a 3A fused jumper wire between the 5-volt reference terminal of the sensor and 5 volts.
3. Install a jumper wire between the low reference terminal of the sensor and ground.
4. Ignition ON, install the J 35555 to the MAP sensor vacuum fitting. See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__special-tools) . Slowly apply vacuum to the sensor while monitoring the voltage between the signal terminal and the low reference terminal. the voltage should vary between 5-0 volts, without any spikes or dropouts. If the voltage is not within the specified range or is erratic, replace the MAP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Manifold Absolute Pressure Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0111

IAT Sensor Temperature

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT signal circuit.

1. DTCs P0112, P0113, P0117, P0118, P0128, P0502, P0503, P0601, P1621, P1627, P1680, P1681, P2610 are not set.
2. The vehicle has had a minimum ignition OFF time of 8 hours.
3. The ignition is ON.
4. The start-up IAT is greater than 10°C (50°F).
5. The Fuel Level Sensor parameter is greater than 2.5 percent.
6. This DTC runs once per ignition cycle within the enabling conditions.

1. The ECM detects a temperature difference at power-up that indicates that the IAT sensor is 30°C (54°F) more than the IAT sensor 2. OR
2. The ECM detects a temperature difference at power-up that indicates that the IAT sensor is 16°C (29°F) more than the IAT sensor 2, and the time spent cranking the engine is more than 30 seconds, when the fuel level is more than 2.5 percent.

DTC P0111 is a Type B DTC.

DTC P0111 is a Type B DTC.

1. An IAT sensor that is skewed lower at various ambient temperatures, due to more resistance than is normal, can widen the spread between the 4 sensors and cause this DTC to set. Measure and record the resistance of the IAT sensor at various ambient temperatures, and then compare those measurements to the Temperature vs. Resistance Table. Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) .
2. Inspect the mass air flow (MAF)/IAT sensor terminals for corrosion.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2, and ECT Sensor parameters. The readings should be within 15°C (27°F) of each other and also the ambient temperature.
2. Engine running, observe the DTC information with a scan tool. DTC P0111 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
2. Test for less than 5 ohms of resistance between the low reference circuit of the IAT terminal D and ground. If greater than the specified range, test the low reference circuit for high resistance. If the circuit tests normal, replace the ECM.
3. Disconnect the harness connector at the IAT sensor 2.
4. Test for less than 5 ohms of resistance between the low reference circuit of the IAT sensor 2 terminal B and ground. If greater than the specified range, test the low reference circuit for high resistance. If the circuit tests normal, replace the ECM.
5. Disconnect the harness connector at the ECM.
6. Test for less than 5 ohms of resistance between the IAT signal circuit terminal E and the corresponding terminal at the ECM. If greater than the specified range, repair the high resistance on the signal circuit.
7. Test for less than 5 ohms of resistance between the IAT sensor 2 signal circuit terminal A and the corresponding terminal at the ECM. If greater than the specified range, repair the high resistance on the signal circuit.
8. If all circuits test normal, test the IAT sensor and the IAT sensor 2. Refer to Component Testing.

Measure and record the resistance of the IAT sensor and IAT sensor 2 at various ambient temperatures, and then compare those measurements to the Temperature vs. Resistance Table. Refer to Temperature Versus Resistance .

1. If the resistance of either sensor is not within 10 percent of the range listed in the Temperature vs Resistance table, replace the affected sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Intake Air Temperature (IAT) Sensor 2 Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Mass Airflow Sensor/Intake Air Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0112 or P0113

IAT Sensor

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT signal circuit.

P0112

1. DTC P0117, P0118, P0116, P0128, P0500, P0608 P0609 are not set.
2. The engine speed is greater than 1 km/h (1 mph).
3. The engine coolant temperature (ECT) sensor is less than 150°C (302°F).
4. The engine run time is more than 10 seconds.
5. DTC P0112 runs continuously within the above enable conditions.

P0113

1. DTC P0101, P0102, P0103, P0117, P0118, P0116, P0128, P0500, P0608 P0609 are not set.
2. The electronic coolant temperature (ECT) sensor is greater than -40°C (-40°F).
3. The mass air flow (MAF) sensor is less than 512 g/s.
4. The engine run time is more than 10 seconds.
5. DTC P0112 runs continuously within the above enable conditions.

P0112

The IAT sensor is more than 148°C (298°F) for more than 5 seconds.

P0113

The IAT sensor is less than -39°C (-38°F) for more than 5 seconds.

DTCs P0112 and P0113 are Type B DTCs.

DTCs P0112 and P0113 are Type B DTCs.

If the engine is cold, then at ignition ON a properly functioning IAT sensor will gradually increase the scan tool IAT Sensor parameter. This is due to the heat that is generated by the MAF sensor heating elements.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Ignition ON, observe the scan tool IAT Sensor, IAT Sensor 2, and ECT Sensor parameters. The readings should be within 15°C (27°F) of each other and also the ambient temperature.
2. Engine running, observe the DTC information with a scan tool. DTCs P0112 or P0113 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the MAF/IAT harness connector at the MAF/IAT sensor.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal D and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool IAT Sensor parameter is less than -39°C (-38°F). If greater than the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal E and a ground. Verify the scan tool IAT Sensor parameter is greater than 149°C (300°F). If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test the MAF/IAT sensor. Refer to Component Testing for instructions.

Compare the IAT sensor resistance to the values listed in the Temperature vs. Resistance table. Refer to Temperature Versus Resistance .

1. If the resistance is not within the range listed in the Temperature vs. Resistance table, replace the IAT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Mass Airflow Sensor/Intake Air Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0116

ECT Sensor Temperature

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT sensor signal circuit and supplies a ground to the low reference circuit.

The ECM uses this high side coolant rationality diagnostic to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the ignition is OFF. If the calibrated ignition OFF time is met at start-up, the ECM will compare the temperature difference between the ECT and the intake air temperature (IAT) to determine if the temperatures are within an acceptable operating range of each other.

1. DTCs P0112, P0113, P0117, P0118, P0128, P0502, P0503, P0601, P1621, P1627, P1680, P1681, P2610 are not set.
2. The vehicle has had a minimum ignition OFF time of 8 hours.
3. The ignition is ON.
4. The start-up IAT is more than 10°C (50°F).
5. The Fuel Level Sensor parameter is more than 2.5 percent.
6. This DTC runs once per ignition cycle within the enabling conditions.

1. The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 30°C (54°F) more than the IAT sensor. OR
2. The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 16°C (29°F) more than the IAT sensor, and the time spent cranking the engine is more than 30 seconds, when the fuel level is more than 2.5 percent. OR
3. The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 16°C (29°F) more than the IAT sensor. Then the vehicle must be driven for more than 6 minutes and 40 seconds at more than 40 km/h (25 mph). If the IAT sensor then decreases more than 5°C (9°F), an engine block heater was detected and the test is aborted. If the IAT sensor does not decrease, an engine block heater was not detected and DTC P0116 will set.

DTC P0116 is a Type B DTC.

DTC P0116 is a Type B DTC.

1. Inspect the ECT sensor terminals for corrosion and for engine coolant leaking through the sensor. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.
2. This diagnostic runs in a specific range. Measure and record the resistance of the ECT sensor at various ambient temperatures greater than -8°C (+18°F), then compare those measurements to the Temperature vs Resistance table. Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) .
3. An IAT sensor that is skewed colder at various ambient temperatures due to greater resistance than is normal will increase the range between these two sensors. Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the Temperature vs Resistance table. Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) .
4. A slight to moderate resistance in the IAT sensor signal circuit or low reference circuit will increase the range between these two sensors. This condition results in a greater voltage on the IAT sensor signal circuit, which is interpreted by the ECM as a colder IAT.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

1. «Powertrain Diagnostic Trouble Code (DTC) Type Definitions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information)
2. «Diagnostic Trouble Code (DTC) Types»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__diagnostic-trouble-code-dtc-types)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Turn OFF the ignition.
2. Inspect the cooling system surge tank for the proper engine coolant level. Refer to «Cooling System Leak Testing (Powertrain)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing-powertrain) or «Cooling System Leak Testing (Charge Air Cooling)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing-charge-air) and «Cooling System Draining and Filling (Static Fill)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-static) or «Cooling System Draining and Filling (GE 47716)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-ge) .
3. If the ignition has been OFF for 8 hours or greater, the ECT and the IAT should be within 15°C (27°F) of each other and also the ambient temperature. Ignition ON, observe the scan tool Start-up ECT and Start-up IAT Sensor parameters. Compare those sensor parameters to each other and also to the ambient temperature to determine if the ECT sensor is skewed warmer.
4. Engine running, observe the DTC information with a scan tool. DTC P0116 should not set.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the ECT harness connector at the ECT sensor.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal Band ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool ECT Sensor parameter is less than -39°C (-38°F). If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT Sensor parameter is greater than 149°C (300°F). If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the ECT sensor.

Measure and record the resistance of the ECT sensor at various ambient temperatures, and then compare those measurements to the Temperature vs. Resistance Table. Refer to Temperature Versus Resistance .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0117 or P0118

ECT Sensor Temperature

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT sensor signal circuit and supplies a ground to the low reference circuit.

P0117

1. The engine is running for more than 10 seconds. OR
2. The engine run time is less than 10 seconds when the intake air temperature (IAT) is less than 50°C (122°F).
3. This DTC runs continuously within the enabling conditions.

P0118

1. The engine is running for more than 10 seconds. OR
2. The IAT is more than 0°C (32°F).
3. This DTC runs continuously within the enabling conditions.

P0117

The ECM detects that the ECT is more than 149°C (300°F) for more than 5 seconds.

P0118

The ECM detects that the ECT is less than -39°C (-38°F) for more than 5 seconds.

DTC P0117 and P0118 are Type B DTCs.

DTC P0117 and P0118 are Type B DTCs.

1. If an engine overheating condition exists, it is possible to set a DTC P0117. Verify the proper heat range and the operation of the thermostat. Refer to «Thermostat Diagnosis»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) .
2. An ECT sensor signal circuit or low reference circuit that is shorted to another 5-volt reference circuit can cause a DTC P0118 to set.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

1. «Powertrain Diagnostic Trouble Code (DTC) Type Definitions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information)
2. «Diagnostic Trouble Code (DTC) Types»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__diagnostic-trouble-code-dtc-types)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Turn OFF the ignition.
2. Inspect the cooling system surge tank for the proper engine coolant level. Refer to «Cooling System Leak Testing (Powertrain)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing-powertrain) or «Cooling System Leak Testing (Charge Air Cooling)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing-charge-air) and «Cooling System Draining and Filling (Static Fill)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-static) or «Cooling System Draining and Filling (GE 47716)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-ge) .
3. Ignition ON, observe the ECT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current ambient temperature and the vehicle operating conditions.
4. Use the scan tool to verify the proper operation of the engine cooling system fans.
5. Engine running, observe the DTC information with a scan tool. DTCs P0117 or P0118 should not set.
6. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the ECT harness connector at the ECT sensor.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal Band ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool ECT Sensor parameter is less than -39°C (-38°F). If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B Verify the scan tool ECT Sensor parameter is greater than 149°C (300°F). If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the ECT sensor.

Measure and record the resistance of the ECT sensor at various ambient temperatures, and then compare those measurements to the Temperature vs Resistance Table. Refer to Temperature Versus Resistance .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0120, P0122, P0123, P0220, P0222, P0223 or P2135

TP Sensor 1

TP Sensor 2

The throttle actuator control (TAC) system uses 2 throttle position (TP) sensors to monitor the throttle position. The TP sensors 1 and 2 are located within the throttle body assembly. Each sensor has a signal circuit and share a 5-volt reference and low reference circuit.

Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to throttle plate movement. Both processors monitor each other's data to verify that the indicated TP calculation is correct.

1. DTCs P0601, P0602, P0603, P0604, P0606, P060D, P062F, P0641, P0651 are not set.
2. The system voltage is more than 5.23 volts.
3. The ignition is in the Unlock/Accessory or Run position.
4. DTCs P0120, P0122, P0123, P0220, P0222, P0223, and P2135 run continuously when the above conditions are met.

P0120

TP sensor 1 voltage is less than 0.35 volt or more than 4.58 volts for more than 0.5 second.

P0122

The ECM detects that the TP sensor 1 voltage is less than 0.35 volt for more than 0.5 second.

P0123

The ECM detects that the TP sensor 1 voltage is more than 4.58 volts for more than 0.5 second.

P0220

The TP sensor 2 voltage is less than 0.35 volt or more than 4.58 volts for more than 0.5 second.

P0222

The ECM detects that the TP sensor 2 voltage is less than 0.35 volt for more than 0.5 second.

P0223

The ECM detects that the TP sensor 2 voltage is more than 4.59 volts for more than 0.5 second.

P2135

The difference between the TP sensor 1 and TP sensor 2 exceeds a predetermined value for more than 0.5 second.

1. DTC P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are a Type A DTC.
2. The control module commands the TAC system to operate in the Reduced Engine Power mode.
3. A message center or an indicator displays Reduced Engine Power.
4. Under certain conditions the control module commands the engine OFF.

DTC P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are a Type A DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Description and Operation

Throttle Actuator Control (TAC) System Description

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Definitions

1. «Powertrain Diagnostic Trouble Code (DTC) Type Definitions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information)
2. «Diagnostic Trouble Code (DTC) Types»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__diagnostic-trouble-code-dtc-types)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Ignition ON, observe the TP sensor 1 for a voltage parameter between 0.35-4.58 volts, with the accelerator pedal in the released position.
2. Ignition ON, observe the TP sensor 2 for a voltage parameter between 0.35-4.597 volts, with the accelerator pedal in the released position with a scan tool.
3. With a scan tool, observe the TP sensors 1 and 2 parameter. The scan tool should indicate Agree.
4. Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC within the conditions that you observed from the Freeze Frame/Failure Records.
5. Ignition OFF for 60 seconds, operate the vehicle within the Conditions for Running the DTCs.
6. Ignition ON, perform several accelerator pedal sweeps, then observe the previous TP sensor parameters and DTC information with the scan tool. If DTC P0120 or P0220 is the only DTC set, and all of the previous TP sensor parameters are normal, replace the ECM.
7. Verify that DTCs P0641 or P0651 are not set. If DTC P0641 or P0651 is set, refer to «DTC P0641 or P0651»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0506-to-p2544) .
8. Engine running, observe the DTC information with a scan tool. DTCs P0120, P0122, P0123, P0220, P0222, P0223 P2135 should not set.
9. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the throttle body. Allow sufficient time for the ECM to completely power down. This can be verified by a no communication message on the scan tool.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal 3 and ground. If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8-5.2 volts between 5-volt reference circuit terminals 5 and ground. If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If less than 5.2 volts, test the affected 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Verify the scan tool TP sensor 1 voltage is less than 0.1 volt. If greater than 0.1 volt, test the signal circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the ECM.
5. Verify the scan tool TP sensor 2 voltage is greater than 4.8 volts. If less than 4.8 volts, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the ECM.
6. Install a 3A fused jumper wire between the signal circuit terminal 1 and the 5-volt reference circuit terminal 5 of the TP sensor 1. Verify the TP sensor 1 voltage is greater than 4.8 volts. If less than 4.8 volts, test the TP sensor 1 signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
7. Install a 3A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 3 of the TP sensor 2. Verify that the TP sensor 2 voltage is less than 0.1 volt. If greater than 0.1 volt, test the TP sensor 2 signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
8. Ignition OFF, disconnect the harness connector at the ECM.
9. Test for less than 5 ohms of resistance on all TP sensor circuits between the following terminals: ECM C2 signal circuit terminal 64 to TP terminal 1 ECM C2 signal circuit terminal 66 to TP terminal 2 ECM C2 5-volt reference circuit terminal 29 to TP terminal 3 If greater than 5 ohms, repair the affected circuit for open/high resistance.
10. Test for infinite resistance between TP sensor 1 signal circuit terminal 1 and TP sensor 2 signal circuit terminal 2. If less than infinite resistance, repair the short between TP sensor 1 signal circuit and TP sensor 2 signal circuits.
11. If all circuits test normal, replace the throttle body.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Throttle Body Assembly Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC P0128

ECT Sensor Temperature

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT sensor signal circuit and supplies a ground to the low reference circuit.

The purpose of this diagnostic is to analyze the performance of the thermostat, by using the ECT sensor to determine if the engine coolant will increase at the correct rate, and also meet the calibrated target temperatures under various operating conditions.

The ECM uses the start-up ECT and the start-up intake air temperature (IAT) to begin the diagnostic calculation. The air flow into the engine is accumulated, and vehicle speed, distance, and engine run time are also factored in to determine if the ECT does increase normally and reach the calibrated target temperatures.

1. DTCs P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0502, P0503 are not set.
2. The start-up IAT is more than -7°C (20°F).
3. The start-up ECT is less than 80°C (176°F).
4. The engine run time is between 60-1,370 seconds.
5. The vehicle has traveled more than 0.8 kilometers (0.5 miles) at more than 8 km/h (5 mph).
6. The mass air flow (MAF) is between 10-35 g/s.
7. This DTC runs once per ignition cycle within the enabling conditions.

The ECM detects that the minimum ECT of 80°C (176°F) has not been met.

DTC P0128 is Type B DTC.

DTC P0128 is Type B DTC.

1. DTC P0128 occurring with insufficient vehicle interior heating is an indication of improper thermostat operation.
2. Inspect the ECT sensor terminals and the ECT harness connector for corrosion. This condition results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.
3. This diagnostic runs in a specific range. Measure and record the resistance of the ECT sensor at various ambient temperatures between -7 to +80°C (+19 to +176°F), then compare those measurements to the Temperature vs Resistance table. Refer to «Temperature Versus Resistance»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__temperature-versus-resistance) .
4. A slight to moderate resistance in the ECT sensor signal circuit or low reference circuit will affect this diagnostic. This condition results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

DTC Type Reference

1. «Powertrain Diagnostic Trouble Code (DTC) Type Definitions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information)
2. «Diagnostic Trouble Code (DTC) Types»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__diagnostic-trouble-code-dtc-types)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Turn OFF the ignition.
2. Inspect the cooling system surge tank for the proper engine coolant level. Refer to «Cooling System Leak Testing (Powertrain)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing-powertrain) or «Cooling System Leak Testing (Charge Air Cooling)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing-charge-air) and «Cooling System Draining and Filling (Static Fill)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-static) or «Cooling System Draining and Filling (GE 47716)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-ge) .
3. If the ignition has been OFF for 8 hours or greater, the ECT and the IAT should be within 15°C (27°F) of each other and also the ambient temperature. Turn ON the ignition, with the engine OFF, and use a scan tool to observe the IAT and the ECT sensor parameters.
4. Use the scan tool to verify the proper operation of the engine cooling system fans.
5. Verify the proper heat range, and the operation of the thermostat. Refer to «Thermostat Diagnosis»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) .
6. Engine running, observe the DTC information with a scan tool. DTC P0128 should not set.
7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the ECT harness connector at the ECT sensor.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal Band ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool ECT Sensor parameter is less than -39°C (-38°F). If greater than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B Verify the scan tool ECT Sensor parameter is greater than 149°C (300°F). If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the ECT sensor.

Measure and record the resistance of the ECT sensor at various ambient temperatures, and then compare those measurements to the Temperature vs Resistance Table. Refer to Temperature Versus Resistance .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Engine Coolant Temperature Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

The supercharger inlet absolute pressure (SCIAP) sensor measures the absolute pressure of the air just after the TB, thus just before the supercharger. The plenum volume between the TB and the supercharger is where this sensor is located, and for the purpose of this diagnostic, this area is considered to be the intake manifold. The diaphragm within the SCIAP sensor functions in the same manner as the barometric pressure (BARO) sensor. These sensors are not interchangeable.

The intake air flow system performance diagnostic provides the within-range rationality test for the mass air flow (MAF), the SCIAP, and the throttle position (TP) sensors. This is an explicit model-based diagnostic containing four separate models for the intake system.

1. The throttle model describes the flow through the throttle body and is used to estimate the MAF through the throttle body as a function of BARO, throttle position, intake air temperature (IAT), and estimated SCIAP.
2. The first intake manifold model describes the intake manifold and is used to estimate SCIAP as a function of the MAF into the intake manifold from the throttle body and the MAF out of the intake manifold caused by engine pumping. The flow into the intake manifold from the throttle uses the MAF estimate calculated from the throttle model.
3. The second intake manifold model is identical to the first intake manifold model except that the MAF sensor measurement is used instead of the throttle model estimate for the throttle air input.
4. A fourth model is created from the combination and additional calculations of the throttle model and the first intake manifold model.

The estimates of the MAF, the SCIAP, and the TP that are obtained from this system of models and calculations are then compared to the actual measured values from the MAF, the SCIAP, and the TP sensors and to each other to determine the appropriate DTC to fail. The following table illustrates the possible failure combinations and the resulting DTC or DTCs.

DTC P012B

If the engine control module (ECM) detects that the actual measured air pressure from the SCIAP sensor is not within range of the calculated air pressure for the SCIAP sensor that is derived from the system of models, DTC P012B sets.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P012B Supercharger Inlet Absolute Pressure (SCIAP) Sensor Performance

1. DTCs P0120, P0121, P0220, P0506, P0507, P012C, P012D, P2135 are not set.
2. The engine speed is between 400-6,400 RPM.
3. The engine coolant temperature (ECT) is between 70-125°C (158-257°F).
4. The IAT is between -7 to +125°C (+19 to +257°F).
5. The change in the TP is less than 5 percent.
6. The above enabling criteria must be stable for more than 5 seconds.
7. DTC P012B runs continuously when the above conditions are met.

The ECM detects that the actual measured air pressure from the SCIAP sensor is not within range of the calculated air pressure for the SCIAP sensor that is derived from the system of models by more than 20 kPa for more than 0.5 second.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P012B

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

DTC P012C or P012D

SCIAP Sensor

SCIAP Sensor, Volts

The supercharger inlet absolute pressure (SCIAP) sensor measures the pressure after the throttle body, but before the supercharger. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature, and barometric pressure (BARO). A diaphragm within the SCIAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The SCIAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The SCIAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the SCIAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is ON while the engine is OFF. Under these conditions, the ECM uses the SCIAP sensor to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. SCIAP can range from 8-10 kPa, when pressures are low, to as much as 207 kPa when pressures are high, depending on the BARO. The ECM monitors the SCIAP sensor signal for pressure outside of the normal range.

P012C

1. DTCs P0120, P0121, P0122, P0123, P0220, P0221, P0222, P0223, P0641 P0651 are not set.
2. The throttle angle is more than 0 percent when the engine speed is less than 800 RPM. OR The throttle angle is more than 12 percent when the engine speed is more than 800 RPM.
3. This DTC runs continuously within the enabling conditions.

P012D

1. DTCs P0120, P0121, P0122, P0123, P0220, P0221, P0222, P0223, P0641 P0651 are not set.
2. The engine has been running for a period of time that is determined by the start-up engine coolant temperature (ECT). The time ranges from 4 minutes at less than -30°C (-22°F) to 2 seconds at more than 30°C (86°F).
3. The throttle angle is less than one percent when the engine speed is less than 1,200 RPM. OR The throttle angle is less than 20 percent when the engine speed is more than 1,200 RPM.
4. This DTC runs continuously within the enabling conditions.

P012C

The ECM detects that the SCIAP sensor voltage is less than 0.10 volt for more than 5 seconds.

P012D

The ECM detects that the SCIAP sensor voltage is more than 4.80 volts for more than 5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

Verify the integrity of the SCIAP sensor system by inspecting for the following conditions

1. Any damage to the SCIAP sensor housing
2. A loose or improperly installed SCIAP sensor
3. A restriction in the vacuum source of the SCIAP sensor

1. With the ignition OFF, disconnect the harness connector at the SCIAP sensor.
2. With the ignition ON and the engine OFF, connect a test lamp between the SCIAP sensor 5-volt reference circuit and a good ground. With a DMM, measure for a voltage range of 4.8-5.2 volts, from the SCIAP sensor 5-volt reference circuit to a ground. If the voltage is less than the specified range, test the circuit for an open, high resistance a short to ground. If the SCIAP sensor 5-volt reference circuit and connections tests normal, replace the ECM. If the voltage is more than the specified range, test the circuit for a short to voltage. If the SCIAP sensor 5-volt reference circuit tests normal, replace the ECM.
3. With the SCIAP sensor harness connector still disconnected, observe the SCIAP Sensor parameter for a value of less than 12 kPa with a scan tool. If the SCIAP Sensor parameter is more than 12 kPa, test the SCIAP sensor signal circuit for a short to voltage. If the SCIAP sensor signal circuit tests normal, replace the ECM.
4. Connect a 3-amp fused jumper wire between the SCIAP sensor 5-volt reference circuit and the signal circuit of the SCIAP sensor and verify the SCIAP sensor parameter is more than 103 kPa. If the SCIAP Sensor parameter is less than 103 kPa, test the SCIAP sensor signal circuit for an open, high resistance a short to ground. If the SCIAP sensor signal circuit tests normal, replace the ECM.
5. Turn OFF the ignition, and all electrical accessories. Allow sufficient time for the control module to power down before taking a resistance measurement. Measure for a value of less than 5 ohms of resistance between the low reference circuit of the SCIAP sensor and a ground. If the resistance is more than 5 ohms, test the circuit for an open or high resistance. If the SCIAP sensor low reference circuit tests normal, replace the ECM. If the SCIAP sensor circuits test normal, replace the SCIAP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Supercharger Inlet Absolute Pressure Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

DTC P0131, P0132, P0137, P0138, P0151, P0152, P0157, P0158, P2A00, P2A01, P2A03 or P2A04

HO2S Sensor 1 Voltage

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The control module supplies the HO2S with a reference bias, voltage of about 450 mV. When the engine is first started, the control module operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust stream.

P0131

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Loop Status parameter is Closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The Throttle Position (TP) Indicated Angle parameter is between 0-50 percent.
6. The equivalence ratio is between 0.99-1.01.
7. DTC P0131 runs the lean test continuously when the above conditions are met for 3 seconds.

P0132

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Loop Status parameter is Closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The Throttle Position (TP) Sensor parameter is between 0-60 percent.
6. The equivalence ratio is between 0.99-1.01.
7. DTC P0132 runs the rich test continuously when the above conditions are met for 3 seconds.

P0137 or P0157

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Loop Status parameter is Closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The Power Enrichment parameter is active for more than 3 seconds.
6. The equivalence ratio is between 0.99-1.01.
7. These DTCs run the power enrichment test during each occurrence of power enrichment, when the above conditions are met for 3 seconds.

P0138 or P0158

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Loop Status parameter is Closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The TP Sensor parameter is between 0-50 percent.
6. The equivalence ratio is between 0.99-1.01.
7. These DTCs run the rich test continuously when the above conditions are met for 3 seconds.

P0151

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Loop Status parameter is Closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The Throttle Position (TP) Sensor parameter is between 0-50 percent.
6. The equivalence ratio is between 0.99-1.01.
7. DTC P0151 runs the test continuously when the above conditions are met for 3 seconds.

P0152

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Loop Status parameter is Closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The Throttle Position (TP) Sensor parameter is between 0-60 percent.
6. The equivalence ratio is between 0.99-1.01.
7. DTC P0152 runs the test continuously when the above conditions are met for 3 seconds.

P2A00

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Engine Run Time parameter is more than 100 seconds.
3. The Engine speed parameter is between 500-5,000 RPM.
4. The Ignition 1 Signal parameter is between 10-18 volts.
5. The Mass Airflow (MAF) Sensor parameter is between 3-30 g/s.
6. The ECT Sensor parameter is more than 70°C (158°F).
7. DTC P2A00 runs continuously when the above conditions are met for 5 seconds.

P2A01 or P2A04 Passive Test

1. DTCs P0030, P0036, P0053, P0054, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1516, P2101, P2119, P2135, P2176, P2A00 are not set.
2. The engine is running.
3. The Engine Run Time parameter is less than 260 seconds.
4. These DTCs run the passive test once per drive cycle when the above conditions are met for 2 seconds.

P2A01 or P2A04 Intrusive Test

1. DTCs P0030, P0036, P0053, P0054, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1516, P2101, P2119, P2135, P2176, P2A00 are not set.
2. The Engine Run Time parameter is more than 260 seconds.
3. The ignition 1 Signal parameter is between 10-18 volts.
4. The MAF sensor parameter is between 0.5-50 g/s.
5. The Engine Speed parameter is between 500-5,000 RPM.
6. The Vehicle Speed parameter is between 24-145 km/h (20-80 mph).
7. The Short Term FT parameter is between 5 and -5 percent.
8. These DTCs run the intrusive test once per drive cycle when the above conditions are met for 1 second.

P2A03

1. DTCs P0030, P0036, P0053, P0054, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1516, P2101, P2119, P2135, P2176, P2A00 are not set.
2. The Engine Run Time parameter is more than 100 seconds.
3. The ignition 1 Signal parameter is between 10-18 volts.
4. The MAF sensor parameter is between 3-30 g/s.
5. The Engine Speed parameter is between 500-5,000 RPM.
6. DTC P2A01 runs continuously when the above conditions are met for 5 seconds.

P0131

1. The control module detects that the HO2S 1 Voltage parameter is less than 25 mV.
2. DTC P0131 sets within 100 seconds during the lean test when the above condition is met.

P0132

1. The control module detects that the HO2S 1 parameter is more than 950 mV.
2. DTC P0132 sets within 15 seconds during the rich test when the above condition is met.

P0137 or P0157 Lean Test

1. The control module detects that the HO2S 2 voltage parameter is less than 75 mV.
2. These DTCs set within 100 seconds during the lean test when the above condition is met.

P0138 or P0158 Rich Test

1. The control module detects that the HO2S 2 voltage parameter is more than 950 mV.
2. These DTCs set within 100 seconds during the rich test when the above condition is met.

P0151

1. The control module detects that the HO2S Bank 2 Sensor 1 Voltage parameter is less than 100 mV.
2. DTC P0151 sets within 3 seconds when the above condition is met.

P0152

1. The control module detects that the HO2S Bank 2 Sensor 1 Voltage parameter is more than 950 mV.
2. DTC P0151 sets within 3 seconds when the above condition is met.

P2A00 or P2A03

1. The control module detects that the Loop Status parameter is open.
2. These DTCs set within 5 seconds when the above condition is met.

P2A01 or P2A04

1. The control module detects that the HO2S 2 did not transition below 299 mV and above 751 mV during the passive test.
2. One of the following tests fail once per trip/runs until pass or fail reporting: Lean Intrusive Test-The control module detects that the HO2S 2 is more than 751 mV for 8 seconds. Rich Intrusive Test-The control module detects that the HO2S 2 is less than 299 mV for 8 seconds.
3. These DTCs set sets within 2 minutes when the above conditions are met.

1. The control module detects that the Loop Status parameter is open by not meeting the voltage criteria to enable close loop fueling. Voltage cannot be between 250-600 mV for 10 seconds after the O2 has seen a ready to go closed loop command.
2. These DTCs set within 5 seconds when the above condition is met.

DTC P0131, P0132, P0137, P0138, P0151, P0152, P0157, P0158, P2A00, P2A01, P2A03, P2A04 are Type B DTCs.

DTC P0131, P0132, P0137, P0138, P0151, P0152, P0157, P0158, P2A00, P2A01, P2A03, P2A04 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)
5. «Heated Oxygen Sensor Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Scan Tool Data List

1. If any HO2S heater DTCs are set, perform those diagnostics first.
2. Allow the engine to reach operating temperature.
3. Engine running, observe the affected HO2S parameter with a scan tool. The pre-catalyst oxygen sensors value should vary from below 200 mV to above 800 mV and respond to fueling changes. The post-catalyst oxygen sensors value should change more than 200 mV when the throttle is quickly cycled 3 times from closed to wide open and back to closed after running the engine at 1,500 RPM for 30 seconds.
4. The affected HO2S may be damaged due to contamination. Prior to replacing the affected HO2S, inspect for the following sources of contamination: NOTE: Refer to «Silicon Contamination of Heated Oxygen Sensors Notice»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#cautions-and-notices__silicon-contamination-of-heated-oxygen-sensors) . A silicon contaminated HO2S Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-troubleshooting) . Engine oil consumption-Refer to «Oil Consumption Diagnosis»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction__oil-consumption-diagnosis) . Engine coolant consumption-Refer to «Loss of Coolant (LH2)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant-lh2) or «Loss of Coolant (LC3)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant-lc3) .

1. Ignition OFF, disconnect the scan tool and wait 60 seconds to ensure all modules are powered down.
2. Ignition OFF, disconnect the harness connector at the appropriate HO2S.
3. Ignition OFF, measure for less than 5 ohms resistance between the appropriate HO2S low signal circuit terminal A and ground. If more than the specified range, test the appropriate HO2S low signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
4. Ignition ON, verify the appropriate scan tool HO2S parameter is approximately 450 mV. If more than the specified value, test the appropriate HO2S high signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. If less than the specified value, test the appropriate HO2S high signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
5. Ignition ON, install a 3-amp fused jumper wire at the HO2S high signal circuit terminal B. Toggle the jumper wire between the HO2S low signal circuit terminal A and battery voltage. Verify the appropriate scan tool HO2S parameter toggles between 0 mV and approximately 1,000 mV. If the appropriate scan tool HO2S parameter does not toggle correctly, test the HO2S high signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
6. If all circuits test normal, replace the appropriate HO2S.

Note. Refer to Heated Oxygen Sensor Resistance Learn Reset Notice .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
4. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
5. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

DTC P0133, P0134, P0140, P0153, P0154, P0160, P1133 or P1153

HO2S Sensor 1 Voltage

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The control module supplies the HO2S with a reference bias, voltage of about 450 mV. When the engine is first started, the control module operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust stream.

DTC P0133 or P0153

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Engine Coolant Temperature (ECT) Sensor parameter is more than 70°C (158°F).
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Level Sensor parameter is more than 10 percent.
5. The Engine Run Time parameter is more than 202 seconds.
6. The Engine Speed parameter is between 1,100-2,500 RPM.
7. The BARO Sensor parameter is more than 70 kPa.
8. The Mass Airflow (MAF) Sensor parameter is between 20-40 g/s.
9. The Loop Status parameter is Closed.
10. The Throttle Position (TP) Indicated Angle parameter is more than 3 percent.
11. These DTCs run once per drive cycle when the above conditions are met for 1 second.

DTC P0134 or P0154

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Ignition 1 Signal parameter is between 10-18 volts.
3. The engine run time is more than 101 seconds.
4. These DTCs run continuously when the above conditions are met.

DTC P0140 or P0160

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The Ignition 1 Signal parameter is between 10-18 volts.
3. The Engine Run Time parameter is more than 101 seconds.
4. The Loop Status parameter is closed.
5. These DTCs run once per drive cycle when the above conditions are met.

DTC P1133 or P1153

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
2. The ECT Sensor parameter is more than 70°C (158°F).
3. The Engine Speed parameter is between 1,100-2,500 RPM.
4. The Ignition 1 Signal parameter is between 10-18 volts.
5. The Engine Run Time parameter is more than 202 seconds.
6. The Loop Status parameter is Closed.
7. The TP Indicated Angle parameter is more than 5 percent.
8. The Fuel Level Sensor parameter is more than 10 percent.
9. The BARO parameter is more than 70 kPa.
10. The MAF Sensor parameter is between 20-40 g/s.
11. These DTCs run once per drive cycle when the above conditions are met for 1 second.

DTC P0133 or P0153

1. The control module detects that the HO2S 1 rich-to-lean or lean-to-rich average response time is more than 0.14 second.
2. These DTCs set within 60 seconds when the above condition is met.

DTC P0134 or P0154

1. The control module detects that the HO2S 1 parameter is between 400-500 mV.
2. The Throttle Position (TP) Indicated Angle parameter changes more than 5 percent.
3. These DTCs set within 101 seconds when the above conditions are met.

DTC P0140 or P0160

1. The control module detects that the HO2S 2 parameter is between 400-500 mV.
2. The TP Indicated Angle parameter changes more than 5 percent 5 times.
3. These DTCs set within 101 seconds when the above conditions are met.

DTC P1133 or P1153

1. The control module detects that the HO2S 1 rich-to-lean counts the lean-to-rich counts are less than a calibrated value.
2. These DTCs set within 60 seconds when the above condition is met.

DTC P0133, P0134, P0140, P0153, P0154, P0160, P1133, P1153 are Type B DTCs.

DTC P0133, P0134, P0140, P0153, P0154, P0160, P1133, P1153 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Engine Controls Connector End Views»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)
5. «Heated Oxygen Sensor Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Scan Tool Data List

1. If any HO2S heater DTCs are set, perform those diagnostics first.
2. Allow the engine to reach operating temperature.
3. Engine running, observe the affected HO2S parameter with a scan tool. The pre-catalyst oxygen sensors value should vary from below 200 mV to above 800 mV and respond to fueling changes. The post-catalyst oxygen sensors value should change more than 200 mV when the throttle is quickly cycled 3 times from closed to wide open and back to closed after running the engine at 1,500 RPM for 30 seconds.
4. The affected HO2S may be damaged due to contamination. Prior to replacing the affected HO2S, inspect for the following sources of contamination: NOTE: Refer to «Silicon Contamination of Heated Oxygen Sensors Notice»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#cautions-and-notices__silicon-contamination-of-heated-oxygen-sensors) . A silicon contaminated HO2S Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-troubleshooting) . Engine oil consumption-Refer to «Oil Consumption Diagnosis»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction__oil-consumption-diagnosis) . Engine coolant consumption-Refer to «Loss of Coolant (LH2)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant-lh2) or «Loss of Coolant (LC3)»(/cadillac/xlr/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant-lc3) .

1. Ignition OFF, disconnect the scan tool and wait 60 seconds to ensure all modules are powered down.
2. Ignition OFF, disconnect the harness connector at the appropriate HO2S.
3. Ignition OFF, measure for less than 5 ohms resistance between the appropriate HO2S low signal circuit terminal A and ground. If more than the specified range, test the appropriate HO2S low signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
4. Ignition ON, verify the appropriate scan tool HO2S parameter is approximately 450 mV. If more than the specified value, test the appropriate HO2S high signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. If less than the specified value, test the appropriate HO2S high signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
5. Ignition ON, install a 3-amp fused jumper wire at the HO2S high signal circuit terminal B. Toggle the jumper wire between the HO2S low signal circuit terminal A and battery voltage. Verify the appropriate scan tool HO2S parameter toggles between 0 mV and approximately 1,000 mV. If the appropriate scan tool HO2S parameter does not toggle correctly, test the HO2S high signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
6. If all circuits test normal, replace the appropriate HO2S.

Note. Refer to Heated Oxygen Sensor Resistance Learn Reset Notice .

1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
4. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
5. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for ECM replacement, setup, and programming

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop (CL). During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During CL, the ECM adds HO2S inputs and level of purge to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicates a rich condition, the FT values will be below 0 percent. The short term FT values change rapidly in response to the HO2S voltage signals. The long term FT makes coarse adjustments in order to maintain an optimum air/fuel ratio. A block of memory cells contain information arranged in combinations of engine RPM and engine load for a full range of vehicle operating conditions. The long term FT diagnostic is based on an average of cells currently being used. The ECM selects the cells based on the engine speed and load. The FT diagnostic will conduct a test to determine if a rich failure actually exists or if excessive vapor from the evaporative emission (EVAP) canister is causing a rich condition.

If the ECM detects an excessively lean condition, DTC P0171 sets. If the ECM detects an excessively rich condition, DTC P0172 sets.

1. DTCs P0030, P0036, P0053, P0054, P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0120, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201-P0208, P0220, P0300, P0308, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0455, P0496, P0506, P0507, P1133, P1516, P2101, P2119, P2120, P2125, P2135, P2138, P2176, P2A00, P2A01 are not set.
2. The engine is in CL status.
3. The Fuel Trim Learn is enabled.
4. The engine coolant temperature (ECT) is between -38 and +150°C (-36.4 and +302°F).
5. The intake air temperature (IAT) is between -38 and +150°C (-36.4 and +302°F).
6. The manifold absolute pressure (MAP) is between 5-255 kPa (0.7-36.9 psi).
7. The vehicle speed is less than 134 km/h (83 mph).
8. The engine speed is between 400-6,000 RPM.
9. The mass air flow (MAF) is between 0.5-510 g/s.
10. The barometric pressure (BARO) is more than 70 kPa (10.1 psi).
11. The fuel level is more than 10 percent.
12. DTC P0171 or P0172 runs continuously when the above conditions have been met.

DTC P0171

1. The average long term FT value is equal to or greater than 24 percent.
2. The above condition is present for more than 2 minutes.
3. The diagnostic runs continuously.

DTC P0172

1. The average long term FT value is equal to or less than -23 percent.
2. The above condition is present for more than 2 minutes.
3. The diagnostic runs continuously.

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second ignition cycle the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. The control module illuminates the malfunction indicator lamp (MIL) when one of the following occur

1. The control module detects the same fuel trim failure during 2 consecutive trips.
2. The control module detects any fuel trim failure during any subsequent trip if the conditions at the time of failure meet the following criteria: The engine load is within 20 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.

1. The control module turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC and related Freeze Frame data clears after 40 warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Emission System Information Reference

1. «Evaporative Emissions Hose Routing Diagram»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Crankcase Ventilation System Inspection/Diagnosis»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction)

Engine Mechanical Information Reference

1. «Symptoms - Engine Mechanical»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction)
2. «Symptoms - Engine Exhaust»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust)

Fuel System Information Reference

1. «Fuel System Diagnosis»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-troubleshooting)
2. «Alcohol/Contaminants-in-Fuel Diagnosis»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-troubleshooting)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Allow the engine to reach operating temperature. With the engine running, observe the HO2S parameter with a scan tool. The HO2S 1 value should vary from approximately 40 mV to approximately 900 mV, and respond to fueling changes.
2. The normal Short Term FT parameter should be moving rapidly between +10 percent and -10 percent, with near 0 percent the optimum, with the engine running at operating temperature.
3. The Long Term FT parameter should be between +10 percent and -10 percent, with near 0 percent the optimum, with the engine running at operating temperature. A larger negative value may be present if EVAP purge is enabled.

DTC P0171

1. Allow the engine to reach operating temperature. With the engine running, observe the Long Term FT parameter with a scan tool. The value should be less than approximately 24 percent with the engine running at operating temperature.
2. If the value is more than 24 percent, inspect for the following: With the ignition ON and the engine OFF, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified for your altitude. Refer to «Altitude Versus Barometric Pressure»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__altitude-versus-barometric-pressure) . If the MAP sensor does not indicate the correct barometric pressure, refer to «DTC P0106»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) and «DTC P0107 or P0108»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
3. Vacuum hoses for splits, kinks, and proper connections
4. Insufficient fuel in the tank
5. A malfunctioning MAF-Refer to «DTC P0068 or P0121»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) or «DTC P0101»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
6. Low fuel pressure
7. Fuel contamination
8. Improperly functioning fuel injectors
9. Missing, loose leaking exhaust components from the HO2S forward
10. Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings
11. The air induction system and the air intake ducts for leaks or for a missing air filter element
12. Evaporative canister purge lines plugged or obstructed
13. Damage to the EVAP canister
14. The crankcase ventilation system for leaks
15. The HO2S for proper installation and for electrical wires or connectors that may have contacted the exhaust system
16. The HO2S signal circuit open, shorted to ground shorted to the low reference circuit
17. The HO2S sensor 1 low signal circuit for an open circuit or high resistance
18. Malfunctioning engine components

DTC P0172

1. Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The value should be more than -23 percent with the engine running at operating temperature.
2. If the value is less than -23 percent, inspect for the following: With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor parameter should be between 19-42 kPa. If the MAP sensor parameter is not between 19-42 kPa, refer to «DTC P0106»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) and «DTC P0107 or P0108»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
3. Vacuum hoses for splits, kinks, and proper connections
4. The inlet screen of the MAF sensor for blockage
5. A malfunctioning MAF-Refer to «DTC P0068 or P0121»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) or «DTC P0101»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
6. The air duct for being collapsed or restricted
7. The air filter for being dirty or restricted
8. Objects blocking the throttle body
9. Excessive fuel in the crankcase
10. A saturated evaporative canister, a stuck purge valve the fuel cap not sealing
11. The evaporative emissions control system for proper operation
12. Excessive fuel pressure
13. Improperly functioning fuel injectors
14. Fuel contamination
15. The HO2S for proper installation and for electrical wires or connectors that may have contacted the exhaust system
16. The HO2S signal circuit shorted to voltage

1. «Air Cleaner Assembly Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Air Cleaner Element Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Evaporative Emission Canister Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
4. «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
5. «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
6. «Evaporative Emission Hoses/Pipes Replacement - Chassis/Canister»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
7. «Fuel Injector and Fuel Rail Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
8. «Fuel Level Sensor Replacement - Left Side»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
9. «Fuel Level Sensor Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
10. «Fuel System Cleaning»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__fuel-system-cleaning)
11. «Fuel Tank Draining»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
12. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) and «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
13. «Manifold Absolute Pressure Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
14. «Throttle Body Assembly Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

1. Install any components that have been removed or replaced during diagnosis.
2. Perform any adjustments, programming setup procedures that are required when a component or module is removed or replaced.
3. Turn ON the ignition, with the engine OFF.
4. Clear the DTCs.
5. Turn OFF the ignition for 60 seconds.
6. Start the engine.
7. Duplicate the Conditions for Running the DTC and use Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) and perform the appropriate diagnostic procedure.

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop (CL). During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During CL, the ECM adds HO2S inputs and level of purge to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicates a rich condition, the FT values will be below 0 percent. The short term FT values change rapidly in response to the HO2S voltage signals. The long term FT makes coarse adjustments in order to maintain an optimum air/fuel ratio. A block of memory cells contain information arranged in combinations of engine RPM and engine load for a full range of vehicle operating conditions. The long term FT diagnostic is based on an average of cells currently being used. The ECM selects the cells based on the engine speed and load. The FT diagnostic will conduct a test to determine if a rich failure actually exists or if excessive vapor from the evaporative emission (EVAP) canister is causing a rich condition.

If the ECM detects an excessively lean condition, DTC P0174 sets. If the ECM detects an excessively rich condition, DTC P0175 sets.

1. DTCs P0050, P0056, P0059, P0060, P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0120, 0122, P0123, P0128, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0201-P0208, P0220, P0222, P0223, P0300, P0301-P0308, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0455, P0496, P0506, P0507, P1153, P1516, P2101, P2119, P2120, P2125, P2135, P2138, P2A03, P2A04 are not set.
2. The engine is in CL status.
3. The Fuel Trim Learn is enabled.
4. The engine coolant temperature (ECT) is between -38 and +150°C (-36.4 and +302°F).
5. The intake air temperature (IAT) is between -38 and +150°C (-36.4 and +302°F).
6. The manifold absolute pressure (MAP) is between 5-255 kPa (0.7-36.9 psi).
7. The vehicle speed is less than 134 km/h (83 mph).
8. The engine speed is between 400-6,000 RPM.
9. The mass air flow (MAF) is between 0.5-510 g/s.
10. The barometric pressure (BARO) is more than 70 kPa (10.1 psi).
11. The fuel level is more than 10 percent.
12. DTC P0174 or P0175 runs continuously when the above conditions have been met.

P0174

1. The average long term FT value is equal to or greater than 24 percent.
2. The above condition is present for more than 2 minutes.
3. The diagnostic runs continuously.

P0175

1. The average long term FT value is equal to or less than -23 percent.
2. The above condition is present for more than 2 minutes.
3. The diagnostic runs continuously.

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second ignition cycle the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. The control module illuminates the malfunction indicator lamp (MIL) when one of the following occur

1. The control module detects the same fuel trim failure during 2 consecutive trips.
2. The control module detects any fuel trim failure during any subsequent trip if the conditions at the time of failure meet the following criteria: The engine load is within 20 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.

1. The control module turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC and related Freeze Frame data clears after 40 warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Emission System Information Reference

1. «Evaporative Emissions Hose Routing Diagram»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Crankcase Ventilation System Inspection/Diagnosis»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction)

Engine Mechanical Information Reference

1. «Symptoms - Engine Mechanical»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-introduction)
2. «Symptoms - Engine Exhaust»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust)

Fuel System Information Reference

1. «Fuel System Diagnosis»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-troubleshooting)
2. «Alcohol/Contaminants-in-Fuel Diagnosis»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-troubleshooting)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Output Controls»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-1-of-2__scan-tool-output-controls)

1. Allow the engine to reach operating temperature. With the engine running, observe the HO2S parameter with a scan tool. The HO2S 1 value should vary from approximately 40 mV to approximately 900 mV, and respond to fueling changes.
2. The normal Short Term FT parameter should be moving rapidly between +10 percent and -10 percent, with near 0 percent the optimum, with the engine running at operating temperature.
3. The Long Term FT parameter should be moving slowly between +10 percent and -10 percent, with near 0 percent the optimum, with the engine running at operating temperature. A larger negative value may be present if EVAP purge is enabled

P0174

1. Allow the engine to reach operating temperature. With the engine running, observe the Long Term FT parameter with a scan tool. The value should be less than approximately 24 percent with the engine running at operating temperature.
2. If the value is more than 24 percent, inspect for the following: With the ignition ON and the engine OFF, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified for your altitude. Refer to «Altitude Versus Barometric Pressure»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__altitude-versus-barometric-pressure) . If the MAP sensor does not indicate the correct barometric pressure, refer to «DTC P0106»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) and «DTC P0107 or P0108»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
3. Vacuum hoses for splits, kinks, and proper connections
4. Insufficient fuel in the tank
5. A malfunctioning MAF-Refer to «DTC P0068 or P0121»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) or «DTC P0101»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
6. Low fuel pressure
7. Fuel contamination
8. Improperly functioning fuel injectors
9. Missing, loose leaking exhaust components from the HO2S forward
10. Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings
11. The air induction system and the air intake ducts for leaks or for a missing air filter element
12. Evaporative canister purge lines plugged or obstructed
13. Damaged EVAP canister
14. The crankcase ventilation system for leaks
15. The HO2S for proper installation and for electrical wires or connectors that may have contacted the exhaust system
16. The HO2S signal circuit open, shorted to ground shorted to the low reference circuit
17. The HO2S sensor 1 low signal circuit for an open circuit or high resistance
18. Malfunctioning engine components

P0175

1. Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The value should be more than -23 percent with the engine running at operating temperature.
2. If the value is less than -23 percent, inspect for the following: With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor parameter should be between 19-42 kPa. If the MAP sensor parameter is not between 19-42 kPa, refer to «DTC P0106»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) and «DTC P0107 or P0108»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
3. Vacuum hoses for splits, kinks, and proper connections
4. The inlet screen of the MAF sensor for blockage
5. A malfunctioning MAF-Refer to «DTC P0068 or P0121»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) or «DTC P0101»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-dtc-p0010-to-p0175) .
6. The air duct for being collapsed or restricted
7. The air filter for being dirty or restricted
8. Objects blocking the throttle body
9. Excessive fuel in the crankcase
10. A saturated evaporative canister, a stuck purge valve the fuel cap not sealing
11. The evaporative emissions control system for proper operation
12. Excessive fuel pressure
13. Improperly functioning fuel injectors
14. Fuel contamination
15. The HO2S for proper installation and for electrical wires or connectors that may have contacted the exhaust system
16. The HO2S signal circuit shorted to voltage

1. «Air Cleaner Assembly Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
2. «Air Cleaner Element Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
3. «Evaporative Emission Canister Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
4. «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
5. «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
6. «Evaporative Emission Hoses/Pipes Replacement - Chassis/Canister»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
7. «Fuel Injector and Fuel Rail Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
8. «Fuel Level Sensor Replacement - Left Side»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
9. «Fuel Level Sensor Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
10. «Fuel System Cleaning»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2__fuel-system-cleaning)
11. «Fuel Tank Draining»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
12. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) and «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
13. «Manifold Absolute Pressure Sensor Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)
14. «Throttle Body Assembly Replacement»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2)

1. Install any components that have been removed or replaced during diagnosis.
2. Perform any adjustments, programming setup procedures that are required when a component or module is removed or replaced.
3. Turn ON the ignition, with the engine OFF.
4. Clear the DTCs.
5. Turn OFF the ignition for 60 seconds.
6. Start the engine.
7. Duplicate the Conditions for Running the DTC and use Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) and perform the appropriate diagnostic procedure.

See also:
• Engine Controls Schematics
• Diagnostic System Check - Vehicle
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Circuit Testing
• Connector Repairs
• Control Module References
• Diagnostic Trouble Code (DTC) List - Vehicle
• Scan Tool Data List
• Scan Tool Data Definitions
• Diagnostic Repair Verification
• Camshaft Timing Drive Chain Alignment Diagram
• Oil Leak Diagnosis
• Oil Consumption Diagnosis
• Camshaft Cleaning and Inspection
• Coolant in Engine Oil
• Oil Pressure Diagnosis and Testing
• Engine Front Cover Disassemble
• Power Distribution Schematics
• Engine Control Module Description
• Heated Oxygen Sensor Resistance Learn Reset Notice
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Measuring Frequency
• Scan Tool Output Controls
• Altitude Versus Barometric Pressure
• DTC P1182
• Special Tools
• Temperature Versus Resistance
• Road Test Caution
• Restricted Exhaust
• Checking Aftermarket Accessories
• Diagnostic Trouble Code (DTC) Types
• Cooling System Leak Testing (Powertrain)
• Cooling System Leak Testing (Charge Air Cooling)
• Cooling System Draining and Filling (Static Fill)
• Cooling System Draining and Filling (GE 47716)
• Thermostat Diagnosis
• Silicon Contamination of Heated Oxygen Sensors Notice
• Alcohol/Contaminants-in-Fuel Diagnosis
• Loss of Coolant (LH2)
• Loss of Coolant (LC3)
• Symptoms - Engine Exhaust
• Fuel System Cleaning
• DTC P0106