Engine Control System & Fuel System - 2.8l, 3.0l - Symptom Troubleshooting and Diagnosis

Diagnostic Instructions

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.

Symptoms Description

Symptoms covers conditions that are not covered by DTCs. Certain conditions can cause multiple symptoms. These conditions are listed together under Symptoms Testing. Conditions that may only cause specific symptoms are listed separately under Additional Symptoms Testing. Perform the Symptoms Testing before using the Additional Symptoms Testing.

Symptoms Verification

Before using the Symptom tables, perform the following inspections

Ensure that the malfunction indicator lamp (MIL) is operating correctly. Use the scan tool to command the lamp ON and OFF.
Ensure that there are no DTCs that are stored.
Ensure that the scan tool data is within a normal operating range. Refer to «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for scan tool information.
Verify the customer concern.
Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.

Identifying Intermittent Conditions

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movements of a component. Refer to the following for a list of issues that may cause an intermittent condition

Moisture and water intrusion in connectors, terminals, and components
Incomplete connector mating
Poor terminal contact
High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
Harness that is too short or tight
Wire insulation that is chaffed or cut
High or low ambient temperature
High or low engine coolant temperatures
High underhood temperatures
Heat build up in component or circuit due to circuit resistance, poor terminal contact, or high electrical load
High or low system voltage
High vehicle load conditions
Rough road surfaces
Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
Incorrect installation of aftermarket, add on accessories

Visual/Physical Check

Ensure that the control module grounds are clean, tight, and correctly located.
Ensure that the vacuum hoses are not split or kinked, and are properly connected, as shown on the Vehicle Emission Control Information label.
Ensure that the air filter is clean and free from restrictions.
Ensure that there is no water intrusion in connectors terminals and components.
Inspect the air intake ducts for the following conditions: Collapsed Damaged areas Looseness Incorrect installation Leaking
Inspect for air leaks at the throttle body mounting area, the mass air flow (MAF) sensor and intake manifold sealing surfaces.
Inspect the wiring harness for the following conditions: Poor connections Pinches Cuts
Inspect for loose, damaged, unseated, or missing sensors/components.
Inspect the terminals for corrosion and correct contact.

Backfire, Cuts Out/Misses, Detonation/Spark Knock, Dieseling/Run-On, Hard Start, Hesitation/Sag/Stumble, Lack of Power/Sluggishness/Sponginess, Poor Fuel Economy, Rough, Unstable, or Incorrect Idle and Stalling, or Surges/Chuggles

Test the fuel system for the following: The fuel system for correct operation volume and pressure - Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . The fuel injectors for proper operation - Refer to «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . The fuel quality condition - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Test ignition system for the following: Spark plugs for incorrect heat range or an abnormal condition - Refer to «Spark Plug Inspection»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__spark-plug-inspection) and «Ignition System Specifications (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__ignition-system-specifications-lf1) . For diagnosis of coolant or oil fouled spark plugs - Refer to «Coolant in Combustion Chamber»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures__coolant-in-combustion-chamber) or «Oil Consumption Diagnosis»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures__oil-consumption-diagnosis) . Wet down the secondary ignition system with water from a spray bottle - Wetting down the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as the water is applied. Weak spark using the J 26792 Spark Tester - Refer to «Electronic Ignition System Diagnosis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Inspect for the following conditions: The proper operation of the transmission torque converter clutch (TCC) - The scan tool should indicate an engine speed drop when the TCC is commanded ON. Refer to «Torque Converter Diagnosis»(/cadillac/srx/ii-2009-2012/remont/automatic-trans/#automatic-transmission-6t706t75-symptom-troubleshooting-and-diagnosis) . The proper operation of the A/C compressor. An engine that runs lean or rich. Observe the Fuel Trim parameters with a scan tool. Inspect the heated oxygen sensors (HO2S). The HO2S should respond quickly to different throttle positions. CAUTION: Refer to «Heated Oxygen and Oxygen Sensor Caution»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#dangers-warnings-and-cautions__heated-oxygen-and-oxygen-sensor-caution) . Water intrusion in the HO2S connector NOTE: The embossed arrows on the mass air flow (MAF) sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Inspect the MAF sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Install the MAF in the proper direction. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . Inspect the mass air flow (MAF) sensor connections. Engine oil contaminated by fuel Vacuum hoses for splits or kinks - Verify that the routing and connections are as shown on the Vehicle Emission Control Information label. Knock sensor (KS) system for excessive spark retard activity - Observe the Knock Retard parameter on the scan tool for activity more than 0°.
The exhaust system components for the following: Physical damage or possible internal failure The three-way catalytic converters for a restriction For more information, refer to «Symptoms - Engine Exhaust»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
Electromagnetic interference (EMI) on the reference circuit can cause a misfire condition. You can usually detect EMI with a scan tool by monitoring the engine speed parameter. A sudden increase in the engine speed parameter with little change in actual engine speed indicates that EMI is present. Inspect the high voltage components near the ignition control circuit if a condition exists.
The crankcase ventilation valve for proper operation - Refer to «Crankcase Ventilation System Inspection/Diagnosis»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) .
Evaporative emission (EVAP) canister purge solenoid that is stuck open
The engine cooling system for the following conditions: The thermostat is the correct heat range. Refer to «Thermostat Diagnosis»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) . Proper engine coolant level - If the level is low, refer to «Loss of Coolant»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
The crankshaft position sensor for an intermittent condition - Observe the scan tool crankshaft position Resync parameter. The Resync parameter should remain at 0 during all operating conditions, and when moving the related harnesses and connectors between the crankshaft position sensor and the ECM.
Inspect the engine for the following mechanical failures: Refer to «Symptoms - Engine Mechanical»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) . Excessive oil in the combustion chamber or leaking valve seals Oil Consumption Incorrect cylinder compression Sticking or leaking valves Worn camshaft lobes Incorrect valve timing Worn rocker arms Broken valve springs Excessive carbon buildup in the combustion chambers - Clean the chambers with top engine cleaner. Follow the instructions on the can. Incorrect engine parts
If the above conditions do not address the symptom, refer to the «Additional Symptoms Tests»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Hard Start

Observe the Throttle Body Idle Airflow Compensation parameter with a scan tool. A value greater than 80% may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .
Test the engine coolant temperature (ECT) sensor. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__temperature-versus-resistance-engine-coolant) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
Verify that the fuel system has adequate pressure for engine start-up. Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) for fuel pressure specifications.
Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) .

Hesitation, Sag, Stumble

Test the fuel pressure. Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Test the generator. Refer to «Symptoms - Engine Electrical»(/cadillac/srx/ii-2009-2012/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) . Repair the charging system if the generator output voltage is less than 9 volts or more than 16 volts.
Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) .
Test the manifold absolute pressure (MAP) sensor. Refer to «DTC P0106 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) .
Engine warm and idling, verify the correct operation of the camshaft position actuator system. Command the intake and exhaust camshaft position actuator for each cylinder bank from 0 degrees to 25 degrees and back to zero while observing the appropriate scan tool Intake Camshaft Position Variance and Exhaust Camshaft Position Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters is greater than 2 degrees, inspect the suspect camshaft actuator and camshaft actuator solenoid valve and valve bore for contamination, obstruction, and damage. Refer to «Camshaft Timing Drive Components Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) and «Camshaft Actuator System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) for additional information.

Poor Fuel Economy

Heavy loads being carried or towed
Acceleration rate too much or too often
Inspect the brake system for brake drag.
Inspect for incorrect operation of the speedometer.
Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (LF1,LFW)»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__engine-control-module-scan-tool-information) list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__temperature-versus-resistance-engine-coolant) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Observe the Throttle Body Idle Airflow Compensation parameter with a scan tool. A value greater than 80% may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .

Detonation spark Knock

Inspect for excessive carbon buildup in the combustion chambers. Clean the chambers with Top Engine Cleaner. Follow the instructions on the can.
Test for an engine overheating condition. Refer to «Engine Overheating»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .
Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (LF1,LFW)»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__engine-control-module-scan-tool-information) list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__temperature-versus-resistance-engine-coolant) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicle minimum octane requirements.

Lack of Power, Hesitation, or Cut Out

Inspect the engine electrical system for correct operation. Refer to «Symptoms - Engine Electrical»(/cadillac/srx/ii-2009-2012/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) .
Verify that each injector harness is connected to the correct injector.
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Engine warm and idling, verify the correct operation of the camshaft position actuator system. Command the intake and exhaust camshaft position actuator for each cylinder bank from 0 degrees to 25 degrees and back to zero while observing the appropriate scan tool Intake Camshaft Position Variance and Exhaust Camshaft Position Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters is greater than 2 degrees, inspect the suspect camshaft actuator and camshaft actuator solenoid valve and valve bore for contamination, obstruction, and damage. Refer to «Camshaft Timing Drive Components Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) and «Camshaft Actuator System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) for additional information.

Rough, Unstable, or Incorrect Idle and Stalling

Observe the Throttle Body Idle Airflow Compensation parameter with a scan tool. A value greater than 80% may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Inspect the engine mounts.
Inspect the intake and exhaust manifolds for casting flash.
Inspect all cylinder 1 intake camshaft position sensor wiring for poor connections. Start the engine and observe for engine stalling while wiggling the cylinder 1 intake camshaft position sensor wiring harness. Refer to «Inducing Intermittent Fault Conditions»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) for further diagnosis.

Surges/Chuggles

Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Test the heated oxygen sensors (HO2S). The HO2S should respond quickly to a change in throttle position. If the HO2S do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The PCM reduces the amount of fuel delivered to the engine, causing a driveability condition.
Verify that each injector harness is connected to the correct injector.

Fuel Odor

Saturated EVAP canister - Refer to «Evaporative Emission Control System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) .
A condition with the internal components of the fuel tank assembly - Refer to «Fuel System Description (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) .
Inspect for damaged or deteriorated fuel lines.

ECM Commanded Reduced Engine Power

Review the Reduced Engine Power Indication History parameter with a scan tool to determine the reason for the last reduced engine power event.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.

Before using the Symptom tables, perform the following inspections

Ensure that the malfunction indicator lamp (MIL) is operating correctly. Use the scan tool to command the lamp ON and OFF.
Ensure that there are no DTCs that are stored.
Ensure that the scan tool data is within a normal operating range. Refer to «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for scan tool information.
Verify the customer concern.
Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.

Moisture and water intrusion in connectors, terminals, and components
Incomplete connector mating
Poor terminal contact
High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
Harness that is too short or tight
Wire insulation that is chaffed or cut
High or low ambient temperature
High or low engine coolant temperatures
High underhood temperatures
Heat build up in component or circuit due to circuit resistance, poor terminal contact, or high electrical load
High or low system voltage
High vehicle load conditions
Rough road surfaces
Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
Incorrect installation of aftermarket, add on accessories

Ensure that the control module grounds are clean, tight, and correctly located.
Ensure that the vacuum hoses are not split or kinked, and are properly connected, as shown on the Vehicle Emission Control Information label.
Ensure that the air filter is clean and free from restrictions.
Ensure that there is no water intrusion in connectors terminals and components.
Inspect the air intake ducts for the following conditions: Collapsed Damaged areas Looseness Incorrect installation Leaking
Inspect for air leaks at the throttle body mounting area, the mass air flow (MAF) sensor and intake manifold sealing surfaces.
Inspect the wiring harness for the following conditions: Poor connections Pinches Cuts
Inspect for loose, damaged, unseated, or missing sensors/components.
Inspect the terminals for corrosion and correct contact.

Test the fuel system for the following: The fuel system for correct operation volume and pressure - Refer to «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . The fuel injectors for proper operation - Refer to «Fuel Injector Solenoid Coil Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . The fuel quality condition - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Test ignition system for the following: Spark plugs for incorrect heat range or an abnormal condition - Refer to «Spark Plug Inspection»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__spark-plug-inspection) and «Ignition System Specifications (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__ignition-system-specifications-lau) . For diagnosis of coolant or oil fouled spark plugs - Refer to «Coolant in Combustion Chamber»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures__coolant-in-combustion-chamber) or «Oil Consumption Diagnosis»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures__oil-consumption-diagnosis) . Wet down the secondary ignition system with water from a spray bottle - Wetting down the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as the water is applied. Weak spark using the J 26792 Spark Tester - Refer to «Electronic Ignition System Diagnosis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Inspect for the following conditions: The proper operation of the transmission torque converter clutch (TCC) - The scan tool should indicate an engine speed drop when the TCC is commanded ON. Refer to «Torque Converter Diagnosis»(/cadillac/srx/ii-2009-2012/remont/automatic-trans/#automatic-transmission-6t706t75-symptom-troubleshooting-and-diagnosis) . The proper operation of the A/C compressor. An engine that runs lean or rich. Observe the Fuel Trim parameters with a scan tool. Inspect the heated oxygen sensors (HO2S). The HO2S should respond quickly to different throttle positions. CAUTION: Refer to «Heated Oxygen and Oxygen Sensor Caution»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#dangers-warnings-and-cautions__heated-oxygen-and-oxygen-sensor-caution) . Water intrusion in the HO2S connector NOTE: The embossed arrows on the mass air flow (MAF) sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Inspect the MAF sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Install the MAF in the proper direction. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . Inspect the mass air flow (MAF) sensor connections. Engine oil contaminated by fuel Vacuum hoses for splits or kinks - Verify that the routing and connections are as shown on the Vehicle Emission Control Information label. Knock sensor (KS) system for excessive spark retard activity - Observe the Knock Retard parameter on the scan tool for activity more than 0°.
The exhaust system components for the following: Physical damage or possible internal failure The three-way catalytic converters for a restriction For more information, refer to «Symptoms - Engine Exhaust»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
Electromagnetic interference (EMI) on the reference circuit can cause a misfire condition. You can usually detect EMI with a scan tool by monitoring the engine speed parameter. A sudden increase in the engine speed parameter with little change in actual engine speed indicates that EMI is present. Inspect the high voltage components near the ignition control circuit if a condition exists.
The crankcase ventilation valve for proper operation - Refer to «Crankcase Ventilation System Inspection/Diagnosis»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) .
Evaporative emission (EVAP) canister purge solenoid that is stuck open
The engine cooling system for the following conditions: The thermostat is the correct heat range. Refer to «Thermostat Diagnosis»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) . Proper engine coolant level - If the level is low, refer to «Loss of Coolant»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
The crankshaft position sensor for an intermittent condition - Observe the scan tool crankshaft position Resync parameter. The Resync parameter should remain at 0 during all operating conditions, and when moving the related harnesses and connectors between the crankshaft position sensor and the ECM.
Inspect the engine for the following mechanical failures: Refer to «Symptoms - Engine Mechanical»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) . Excessive oil in the combustion chamber or leaking valve seals Oil Consumption Incorrect cylinder compression Sticking or leaking valves Worn camshaft lobes Incorrect valve timing Worn rocker arms Broken valve springs Excessive carbon buildup in the combustion chambers - Clean the chambers with top engine cleaner. Follow the instructions on the can. Incorrect engine parts
If the above conditions do not address the symptom, refer to the «Additional Symptoms Tests»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .
Test the engine coolant temperature (ECT) sensor. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__temperature-versus-resistance-engine-coolant) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
Verify that the fuel system has adequate pressure for engine start-up. Refer to «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) for fuel pressure specifications.
Test the operation of the auxiliary coolant pump. An inoperative auxiliary coolant pump may cause fuel to boil in the fuel rail resulting in a vapor lock condition after a brief hot-soak - Refer to «After Boil Coolant Pump Inoperative»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) or «After Boil Coolant Pump Malfunction»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system) .
Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) .

Test the fuel pressure. Refer to «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Test the generator. Refer to «Symptoms - Engine Electrical»(/cadillac/srx/ii-2009-2012/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) . Repair the charging system if the generator output voltage is less than 9 volts or more than 16 volts.
Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) .
Engine warm and idling, verify the correct operation of the camshaft position actuator system. Command the intake and exhaust camshaft position actuator for each cylinder bank from 0 degrees to 25 degrees and back to zero while observing the appropriate scan tool Intake Camshaft Position Variance and Exhaust Camshaft Position Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters is greater than 2 degrees, inspect the suspect camshaft actuator and camshaft actuator solenoid valve and valve bore for contamination, obstruction, and damage. Refer to «Camshaft Timing Drive Components Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) and «Camshaft Actuator System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) for additional information.

Heavy loads being carried or towed
Acceleration rate too much or too often
Inspect the brake system for brake drag.
Inspect for incorrect operation of the speedometer.
Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (LAU)»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__engine-control-module-scan-tool-information) list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__temperature-versus-resistance-engine-coolant) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) or «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .

Detonation/Spark Knock

Inspect for excessive carbon buildup in the combustion chambers. Clean the chambers with Top Engine Cleaner. Follow the instructions on the can.
Test for an engine overheating condition. Refer to «Engine Overheating»(/cadillac/srx/ii-2009-2012/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .
Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (LAU)»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__engine-control-module-scan-tool-information) list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__temperature-versus-resistance-engine-coolant) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicle minimum octane requirements.

Ensure that the turbocharger air inlet and outlet ducts are tightly sealed and that the air passages are not obstructed. Inspect the turbocharger moving components for looseness, binding, wear, and damage. Refer to «Turbocharger System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation__turbocharger-system-description) and «Turbocharger Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-1-of-5__turbocharger-cleaning-and-inspection) .
Inspect the engine electrical system for correct operation. Refer to «Symptoms - Engine Electrical»(/cadillac/srx/ii-2009-2012/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) .
Verify that each injector harness is connected to the correct injector.
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Engine warm and idling, verify the correct operation of the camshaft position actuator system. Command the intake and exhaust camshaft position actuator for each cylinder bank from 0 degrees to 25 degrees and back to zero while observing the appropriate scan tool Intake Camshaft Position Variance and Exhaust Camshaft Position Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters is greater than 2 degrees, inspect the suspect camshaft actuator and camshaft actuator solenoid valve and valve bore for contamination, obstruction, and damage. Refer to «Camshaft Timing Drive Components Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) and «Camshaft Actuator System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) for additional information.

Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .
Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Inspect the engine mounts.
Inspect the intake and exhaust manifolds for casting flash.
Inspect all cylinder 1 intake camshaft position sensor wiring for poor connections. Start the engine and observe for engine stalling while wiggling the cylinder 1 intake camshaft position sensor wiring harness. Refer to «Inducing Intermittent Fault Conditions»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) for further diagnosis.

Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Test the heated oxygen sensors (HO2S). The HO2S should respond quickly to a change in throttle position. If the HO2S do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The PCM reduces the amount of fuel delivered to the engine, causing a driveability condition.
Verify that each injector harness is connected to the correct injector.

Saturated EVAP canister - Refer to «Evaporative Emission Control System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) .
A condition with the internal components of the fuel tank assembly - Refer to «Fuel System Description (LAU or LY7)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) .
Inspect for damaged or deteriorated fuel lines.

Review the Reduced Engine Power Indication History parameter with a scan tool to determine the reason for the last reduced engine power event.

Poor Fuel Fill Quality

Problem	Causes
DEFINITION: During the fueling process a continual, occasional or no fuel nozzle shut-off condition has occurred.
Difficult to fill	Fuel fill limiter vent valve stuck closed Evaporative emission (EVAP) canister restricted EVAP vent valve stuck closed Hose between canister and canister vent solenoid twisted or kinked if applicable High fuel temperature Fuel filler hose is kinked Faulty dispensing nozzle Ignition switch ON, vent valve closed
Over fill	Fill limiter vent valve stuck open or leaking Fuel inlet check valve stuck open
Pre-mature shut-off of the fuel dispensing nozzle occurs immediately after engaging dispensing nozzle, tank empty	Restricted vapor lines or fuel fill pipe High fuel temperature Inlet check valve at tank stuck closed, fill pipe full of fuel Fuel tank full, gauge not accurate
Pre-mature shut-off of the fuel dispensing nozzle, more than 1/8 of tank capacity dispensed	Kinked, pinched or plugged lines in fuel tank vent system EVAP vent valve stuck closed or restricted EVAP canister restricted Fuel limiting vent valve stuck closed or obstruction at top of fuel tank
Fuel Spitback	Restricted EVAP canister High fuel temperature Ignition switch ON, EVAP vent valve closed

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

Ignition voltage is supplied to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control circuit.

Diagnostic Aids

If the condition is intermittent, move the related harnesses and connectors with the engine operating. Monitor the scan tool Circuit Test Status parameters for the component. The Circuit Test Status parameter will change from OK or Not run to Fault if there is a condition with the circuit or a connection.

Reference Information

Schematic Reference

«Instrument Cluster Schematics»(/cadillac/srx/ii-2009-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
«Engine Controls Schematics (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-schematic-routing-diagrams) or «Engine Controls Schematics (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-schematic-routing-diagrams)

Connector End View Reference

Component Connector End Views

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool MIL Circuit Test Status parameters. Each of the MIL circuit test status parameters should display OK or Not Run.
Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

If any other IPC indicators or gauges are inoperative, refer to «Instrument Cluster Gauges Inoperative»(/cadillac/srx/ii-2009-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges) .
Ignition OFF, disconnect the ECM harness connectors. Ignition ON, the MIL should not illuminate. If the MIL is illuminated, test the MIL control circuit terminal 12-X2 for a short to ground. If the circuit tests normal, replace the IPC.
Ignition ON, connect a 3 A fused jumper wire between the MIL control circuit terminal 12-X2 and ground. The MIL should illuminate. If the MIL does not illuminate, test the MIL control circuit for a short to voltage, or an open/high resistance. If the circuit test normal, replace the IPC/bulb.
If all circuits/connections test normal, replace the ECM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references)
«Instrument Cluster Replacement»(/cadillac/srx/ii-2009-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This Engine Cranks but Does Not Run diagnostic procedure is an organized approach to identify a condition which causes the engine to crank but not start. This diagnostic procedure directs the technician to the appropriate system diagnosis.

Inspect for any of the following conditions

When attempting to start the engine, the mechanical portion of the vehicle key must be locked in the fully extended position with the fob parallel to the key. Leaving the key partially retracted or folded over when starting may interrupt transponder authentication and result in an intermittent no-start condition. In such instances, DTC B3055 may also be set. If an intermittent no-start complaint is received, it may be necessary to discuss with the customer their starting habits and verify they are locking the key in the fully extended position, fob parallel to the key, before starting.
The engine control module (ECM) uses the camshaft position (CMP) sensors to determine engine speed and position when there is a crankshaft position (CKP) sensor condition.
The engine will operate with a CKP sensor condition only if the ECM has stored the learned reference position of the camshafts in memory. With a CKP sensor condition in the signal circuit, the engine will go into a limp home mode after a hard restart. The ECM then calculates engine speed from one of the CMP sensors.
The fuel pump control module controls and monitor. When attempting to start the engine, the mechanical portion of the vehicle key must be locked in the fully extended position with the fob parallel to the key. Leaving the key partially retracted or folded over when attempting to start the engine may interrupt transponder authentication and result in an intermittent engine cranks but does not run condition. In such instances, DTC B3055 may also be set. If an intermittent engine cranks but does not run complaint is received, it may be necessary to discuss with the customer their starting habits and verify they are locking the key in the fully extended position, fob parallel to the key, before attempting to start the engine, check the operation of the in-tank fuel pump. If the fuel pump control module detects a fault, a DTC sets in the fuel pump control module. The fuel pump control module will then send a serial data message to the engine control module (ECM) requesting the illumination of the malfunction indicator lamp (MIL).
Insufficient fuel can cause a no start condition. Thoroughly inspect the fuel delivery system for sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.
Fuel injectors with partially blocked and restricted nozzles, or a malfunctioning solenoid, can cause a no start condition. Refer to «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
There may be fuel spray at the fuel injectors and the indicated fuel pressure may be correct, yet there may not be enough fuel to start the engine. If the fuel injectors and the injector circuit are OK, and fuel spray is detected, the fuel injector ON time may be inadequate. If the engine control module (ECM) receives incorrect inputs from the various information sensors, the fuel delivered by the fuel injectors may be inadequate to start the engine. Check all the engine data parameters with a scan tool and compare the values indicated with the expected values or the values from a known good vehicle.
Inspect the engine for good secure electrical grounds.
Water or foreign material in the fuel can cause a no start or engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 min in a heated repair shop. The malfunction may not recur until parked overnight in freezing temperatures. Extreme weather conditions can cause contaminated fuel to prevent the vehicle from starting.
A vehicle that starts and runs after being brought to the repair shop for a no start condition, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and the wiring in order to check for an engine starting or will not stay running concern.

Schematic Reference

Engine Controls Schematics (LF1)

Connector End View Reference

Component Connector End Views

Description and Operation

«Electronic Ignition System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation__electronic-ignition-system-description)
«Fuel System Description (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation) .
«Immobilizer Description and Operation»(/cadillac/srx/ii-2009-2012/remont/door-locks-anti-theft-systems/#immobilizer-system__immobilizer-description-and-operation)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Verify there is adequate fuel in the fuel tank.
Ignition ON, test the fuses that are supplied voltage by the powertrain relay. The test lamp should illuminate for each test point of the fuses. If the test lamp does not illuminate for at least one test point of each fuse, refer to «DTC P0685 or P0690 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0455-to-dtc-p150cp1400) for powertrain relay system diagnosis.
Engine cranking, observe the Engine Speed parameter with a scan tool. The reading should show engine speed greater than 175 RPM. If the cranking speed is slow, refer to «Engine Cranks Slowly»(/cadillac/srx/ii-2009-2012/remont/charging-system/#battery-charging-system-and-starting-system) . If engine speed reading is 0 RPM, refer to «DTC P0335 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0300-to-dtc-p0455) for crankshaft position sensor diagnosis.
Ignition ON, observe the ECM, fuel pump control module, and theft deterrent module DTC information with a scan tool. No DTCs should be set. If there are any DTCs set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for diagnosis.
Disconnect the B75B mass airflow (MAF) sensor. Attempt to start the engine. The ECM will ignore MAF sensor input, default to calculated airflow, and the engine should start and run if the MAF sensor is faulted. If the engine starts and runs, and the MAF sensor circuits test OK, replace the B75B MAF sensor.
Ignition OFF, inspect the engine air filter, intake duct, and B75B MAF sensor. The air way should be clear. If the intake duct is blocked or collapsed, or the filter is restricted or water saturated, repair or replace as necessary. If the MAF sensor is damaged or contains water, replace it.
Observe the Throttle Body Idle Airflow Compensation parameter with a scan tool. The reading should be less than 80%. If the reading is greater than 80%, inspect the Q38 throttle body bore for excessive carbon deposits and clean the throttle body. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .
Ignition ON, observe the BARO parameter with a scan tool. Determine your altitude and compare the BARO reading to the «Altitude Versus Barometric Pressure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__altitude-versus-barometric-pressure) table. The reading should be within the range specified. If the reading is not within the specified range in the table, and the barometric pressure sensor circuits test OK, replace the B17 barometric pressure sensor.
Perform the «Electronic Ignition System Diagnosis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) to verify the ignition system provides spark to the cylinders.
Ignition OFF, remove and inspect the engine spark plugs. They should be dry. If the spark plugs are coolant fouled, refer to «Coolant in Combustion Chamber»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures__coolant-in-combustion-chamber) . If the spark plugs are fuel fouled, replace the spark plugs.
Collect a fuel sample from the fuel tank. The sample should be bright and clear, free of water, dirt, or other debris. Also, verify the fuel is the correct type for this engine. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . If the fuel is contaminated with water, dirt, or other debris, replace the fuel filter and refer to «Fuel System Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-system-cleaning) . If the fuel is not the correct type, drain the fuel system and the fuel tank and replace with the correct type.
Perform the «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) to verify proper fuel pump operation and fuel pressure.
Ignition ON, observe the ECT Sensor parameter with a scan tool. Compare the parameter reading to the actual engine coolant temperature. The readings should be within ±3°C (±5°F). If the temperature readings are not within the ±3°C (±5°F) of each other and the ECT sensor circuits test OK, replace the B34 ECT sensor.
Test the engine compression. Refer to «Engine Compression Test»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) . The compression should be within specification. If engine compression is not within specification, repair the engine as necessary.
Inspect the exhaust system. The exhaust system should be free of restrictions. Refer to «Restricted Exhaust»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system) . If a restriction or blockage is found, repair the exhaust system as necessary.
Ignition OFF, inspect the timing chain and sprockets. They should be properly aligned, free of damage, with minimal wear. Refer to «Setting Camshaft Timing»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-on-vehicle-2-of-2__setting-camshaft-timing) and «Camshaft Timing Drive Components Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) . If a condition is found, repair the engine as necessary.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Air Cleaner Element Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Air Cleaner Outlet Duct Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
«Spark Plug Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Engine Coolant Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Inspect for any of the following conditions

When attempting to start the engine, the mechanical portion of the vehicle key must be locked in the fully extended position with the fob parallel to the key. Leaving the key partially retracted or folded over when starting may interrupt transponder authentication and result in an intermittent no-start condition. In such instances, DTC B3055 may also be set. If an intermittent no-start complaint is received, it may be necessary to discuss with the customer their starting habits and verify they are locking the key in the fully extended position, fob parallel to the key, before starting.
The engine control module (ECM) uses the camshaft position sensors to determine engine speed and position when there is a crankshaft position sensor condition.
The engine will operate with a crankshaft position sensor condition only if the ECM has stored the learned reference position of the camshafts in memory. With a crankshaft position sensor condition in the signal circuit, the engine will go into a limp home mode after a hard restart. The ECM then calculates engine speed from one of the camshaft position sensors.
The fuel pump control module controls and monitors the operation of the in-tank fuel pump. If the fuel pump control module detects a fault, a DTC sets in the fuel pump control module. The fuel pump control module will then send a serial data message to the engine control module (ECM) requesting the illumination of the malfunction indicator lamp (MIL).
Insufficient fuel can cause a no start condition. Thoroughly inspect the fuel delivery system for sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.
Fuel injectors with partially blocked and restricted nozzles, or a malfunctioning solenoid, can cause a no start condition. Refer to «Fuel Injector Solenoid Coil Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
There may be fuel spray at the fuel injectors and the indicated fuel pressure may be correct, yet there may not be enough fuel to start the engine. If the fuel injectors and the injector circuit are OK, and fuel spray is detected, the fuel injector ON time may be inadequate. If the engine control module (ECM) receives incorrect inputs from the various information sensors, the fuel delivered by the fuel injectors may be inadequate to start the engine. Check all the engine data parameters with a scan tool and compare the values indicated with the expected values or the values from a known good vehicle.
Inspect the engine for good secure electrical grounds.
Water or foreign material in the fuel can cause a no start or engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 min in a heated repair shop. The malfunction may not recur until parked overnight in freezing temperatures. Extreme weather conditions can cause contaminated fuel to prevent the vehicle from starting.
A vehicle that starts and runs after being brought to the repair shop for a no start condition, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and the wiring in order to check for an engine starting or will not stay running concern.

Schematic Reference

Engine Controls Schematics (LAU)

Connector End View Reference

Component Connector End Views

Description and Operation

«Electronic Ignition System Description»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation__electronic-ignition-system-description)
«Fuel System Description (LAU or LY7)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-description-operation)
«Immobilizer Description and Operation»(/cadillac/srx/ii-2009-2012/remont/door-locks-anti-theft-systems/#immobilizer-system__immobilizer-description-and-operation)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Verify there is adequate fuel in the fuel tank.
Ignition ON, test the fuses that are supplied voltage by the powertrain relay. The test lamp should illuminate for each test point of the fuses. If the test lamp does not illuminate for at least one test point of each fuse, refer to «DTC P0685, P0686, P0687, P0689, or P0690 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0455-to-dtc-p150cp1400) for powertrain relay system diagnosis.
Engine cranking, observe the Engine Speed parameter with a scan tool. The reading should show engine speed greater than 175 RPM. If the cranking speed is slow, refer to «Engine Cranks Slowly»(/cadillac/srx/ii-2009-2012/remont/charging-system/#battery-charging-system-and-starting-system) . If engine speed reading is 0 RPM, refer to «DTC P0335 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0300-to-dtc-p0455) for crankshaft position sensor diagnosis.
Ignition ON, observe the ECM, fuel pump control module, and theft deterrent module DTC information with a scan tool. No DTCs should be set. If there are any DTCs set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for diagnosis.
Disconnect the B75B mass airflow (MAF) sensor. Attempt to start the engine. The ECM will ignore MAF sensor input, default to calculated airflow, and the engine should start and run if the MAF sensor is faulted. If the engine starts and runs, and the MAF sensor circuits test OK, replace the B75B MAF sensor.
Ignition OFF, inspect the engine air filter, intake duct, and B75B MAF sensor. The air way should be clear. If the intake duct is blocked or collapsed, or the filter is restricted or water saturated, repair or replace as necessary. If the MAF sensor is damaged or contains water, replace it.
Inspect the Q38 throttle body. The throttle body should be clean and free of carbon deposits. Refer to «Throttle Body Inspection and Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__throttle-body-inspection-and-cleaning) .
Ignition ON, observe the BARO parameter with a scan tool. Determine your altitude and compare the BARO reading to the «Altitude Versus Barometric Pressure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__altitude-versus-barometric-pressure) table. The reading should be within the range specified. If the reading is not within the specified range in the table, and the ECM atmospheric vent is free of moisture and debris, replace the K20 ECM.
Perform the «Electronic Ignition System Diagnosis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) to verify the ignition system provides spark to the cylinders.
Ignition OFF, remove and inspect the engine spark plugs. They should be dry. If the spark plugs are coolant fouled, refer to «Coolant in Combustion Chamber»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures__coolant-in-combustion-chamber) . If the spark plugs are fuel fouled, replace the spark plugs.
Collect a fuel sample from the fuel tank. The sample should be bright and clear, free of water, dirt, or other debris. Also, verify the fuel is the correct type for this engine. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . If the fuel is contaminated with water, dirt, or other debris, replace the fuel filter and refer to «Fuel System Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-system-cleaning) . If the fuel is not the correct type, drain the fuel system and the fuel tank and replace with the correct type.
Perform the «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) to verify proper fuel pump operation and fuel pressure.
Ignition ON, observe the ECT Sensor parameter with a scan tool. Compare the parameter reading to the actual engine coolant temperature. The readings should be within ±3°C (±5°F). If the temperature readings are not within the ±3°C (±5°F) of each other and the ECT sensor circuits test OK, replace the B34 ECT sensor.
Test the engine compression. Refer to «Engine Compression Test»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) . The compression should be within specification. If engine compression is not within specification, repair the engine as necessary.
Inspect the exhaust system. The exhaust system should be free of restrictions. Refer to «Restricted Exhaust»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system) . If a restriction or blockage is found, repair the exhaust system as necessary.
Ignition OFF, inspect the timing chain and sprockets. They should be properly aligned, free of damage, with minimal wear. Refer to «Setting Camshaft Timing»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-on-vehicle-2-of-2__setting-camshaft-timing) and «Camshaft Timing Drive Components Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-2-of-5) . If a condition is found, repair the engine as necessary.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Air Cleaner Element Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Air Cleaner Inlet Duct Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Engine Control Module Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Air Cleaner Outlet Duct Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Spark Plug Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Engine Coolant Temperature Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) or «Engine Coolant Temperature Sensor Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

Diagnostic Fault Information

Circuit	Short to Ground	Open or High Resistance	Short to Voltage	Signal Performance
Fuel Pump High Signal	P0231	P023F	P0232	P023F, P2635
Fuel Pump Low Signal		P023F		P023F, P2635

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module remains active for two seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump control module closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

Schematic Reference

Engine Controls Schematics (LAU) or Engine Controls Schematics (LF1)

Connector End View Reference

Component Connector End Views

Description and Operation

Fuel System Description (LF1) or Fuel System Description (LAU or LY7)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the fuel pump ON and OFF using the scan tool ECM output control. The fuel pump should turn on and off.

Ignition OFF, disconnect the harness connector at the G12 fuel pump.
Connect a test lamp between the control circuit terminal A and ground.
Ignition ON, command the G12 fuel pump ON and OFF using a scan tool ECM fuel pump output control. The test lamp should turn ON and OFF, as commanded. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
Ignition OFF, connect a test lamp between the control circuit terminal A and the low reference circuit terminal B.
Ignition ON, command the G12 fuel pump ON using a scan tool. The test lamp should illuminate. If the test lamp does not illuminate, test the low reference circuit terminal A for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
If all circuits test normal, replace the G12 fuel pump.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for fuel pump control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is ON. The voltage from the ECM to the fuel pump control module remains active for two seconds, unless the engine is in Crank or Run. While this voltage is being received, the fuel pump control module closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank module in order to maintain the desired fuel rail pressure.

The fuel system is an electronic returnless on-demand design. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.

An electric turbine style fuel pump attaches to the primary fuel pump module inside the fuel tank. The fuel pump supplies fuel through the fuel filter and the fuel feed pipe to the high pressure fuel pump. The high pressure fuel pump supplies fuel to a variable-pressure fuel rail. Fuel enters the combustion chamber through precision multi-hole fuel injectors. The high pressure fuel pump, fuel rail pressure, fuel injection timing, and injection duration are controlled by the engine control module (ECM).

The primary fuel tank module also contains a primary jet pump and a secondary jet pump. Fuel pump flow loss, caused by vapor expulsion in the pump inlet chamber, is diverted to the primary jet pump and the secondary jet pump through a restrictive orifice located on the pump cover. The primary jet pump fills the reservoir of the primary fuel tank module. The secondary jet pump creates a venturi action which causes the fuel to be drawn from the secondary side of the fuel tank, through the fuel transfer pipe, to the primary side of the fuel tank.

Description and Operation

Fuel System Description (LF1) or Fuel System Description (LAU or LY7)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

CH 48027: Digital Pressure Gauge
J 37287: Fuel Line Shut-off Adapter
For equivalent regional tools, refer to «Special Tools»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-special-tools-equipment) .

Note. Repair all fuel system related DTCs before performing this diagnostic. Inspect the fuel system for damage or external leaks before proceeding. Verify that adequate fuel is in the fuel tank before proceeding. The Fuel Pump Enable may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. Before proceeding with this test review the User Manual CH 48027-5 for Safety Information and Instructions.

Ignition OFF, all accessories OFF, install a CH 48027: Gauge. Refer to «Fuel Pressure Gauge Installation and Removal»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Ignition ON, engine OFF, command the fuel pump ON with a scan tool. Verify the fuel pressure is between 276-448 kPa (40-65 psi) and does not decrease more than 34 kPa (5 psi) in 1 min.
Engine idling at normal operating temperature, verify the scan tool Fuel Pump Control Module Fuel Pressure Sensor parameter is between 297-400 kPa (43-58 psi).

Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool and observe the fuel pressure gauge while the fuel pump is operating. Verify the fuel pressure is between 276-448 kPa (40-65 psi). If the fuel pressure is greater than the specified range test for a restriction in the return side of the fuel filter. If the fuel filter tests normal, replace the primary fuel tank module. If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Restricted or plugged fuel filter Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 min. If the fuel pressure decreases more than the specified value, perform the following procedure: Ignition OFF, relieve the fuel pressure. Refer to «Fuel Pressure Relief»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-pressure-relief) . Install the J 37287: Adapter between the chassis fuel feed hose and the engine compartment fuel feed pipe. Open the valve on the J 37287: Adapter. Ignition ON, command the Fuel Pump Enable ON with a scan tool and bleed the air from the CH 48027: Gauge. Command the Fuel Pump Enable ON and then OFF with a scan tool. Close the valve on the J 37287: Adapter. Monitor the fuel pressure for 1 min. If the fuel pressure does not decrease more than 34 kPa (5 psi) within the specified time, replace the primary fuel tank module.
Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 min. If the fuel pressure decreases more than the specified value, replace the primary fuel tank module.
Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027: Gauge. The fuel pressure should not drop off during acceleration, cruise or hard cornering. If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Restricted or plugged fuel filter Inspect the harness connectors and the ground circuits of the fuel pump for poor connections
If the fuel system tests normal, refer to «Symptoms - Engine Controls (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) and «Fuel Injector Balance Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Feed Pipe Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Filter Replacement (China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Line Replacement - Chassis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Primary Fuel Tank Module Replacement (NT7, NU5)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) or or «Primary Fuel Tank Module Replacement (China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

An electric turbine style fuel pump attaches to the primary fuel pump module inside the fuel tank. The fuel pump supplies fuel through the fuel feed pipe to the high pressure fuel pump. The high pressure fuel pump supplies fuel to a variable-pressure fuel rail. Fuel enters the combustion chamber through precision multi-hole fuel injectors. The high pressure fuel pump, fuel rail pressure, fuel injection timing, and injection duration are controlled by the engine control module (ECM).

Description and Operation

Fuel System Description (LF1) .

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

CH 48027: Digital Pressure Gauge
J 37287: Fuel Line Shut-off Adapter

Ignition OFF, all accessories OFF, install a CH 48027: Gauge. Refer to «Fuel Pressure Gauge Installation and Removal»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Ignition ON, engine OFF, command the fuel pump ON with a scan tool. Verify the fuel pressure is between 276-448 kPa (40-65 psi) and does not decrease more than 34 kPa (5 psi) in 1 min.
Engine idling at normal operating temperature, verify the scan tool Fuel Pump Control Module Fuel Pressure Sensor parameter is between 297-400 kPa (43-58 psi).

Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool and observe the fuel pressure gauge while the fuel pump is operating. Verify the fuel pressure is between 276-448 kPa (40-65 psi). If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 min. If the fuel pressure decreases more than the specified value, perform the following procedure: Ignition OFF, relieve the fuel pressure. Refer to «Fuel Pressure Relief»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-pressure-relief) . Install the J 37287: Adapter between the chassis fuel feed hose and the engine compartment fuel feed pipe. Open the valve on the J 37287: Adapter. Ignition ON, command the Fuel Pump Enable ON with a scan tool and bleed the air from the CH 48027: Gauge. Command the Fuel Pump Enable ON and then OFF with a scan tool. Close the valve on the J 37287: Adapter. Monitor the fuel pressure for 1 min. If the fuel pressure does not decrease more than 34 kPa (5 psi) within the specified time, replace the primary fuel tank module.
Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 min. If the fuel pressure decreases more than the specified value, replace the primary fuel tank module.
Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027: Gauge. The fuel pressure should not drop off during acceleration, cruise or hard cornering. If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections
If the fuel system tests normal, refer to «Symptoms - Engine Controls (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) and «Fuel Injector Balance Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Feed Pipe Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Line Replacement - Chassis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Primary Fuel Tank Module Replacement (NT7, NU5)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

An electric turbine style fuel pump attaches to the primary fuel tank module inside the fuel tank. The fuel pump supplies fuel through the fuel filter and the fuel feed pipe to the fuel injection system. The primary fuel tank module contains a reverse flow check valve. The check valve maintains fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.

Description and Operation

Fuel System Description (LF1) .

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

CH 48027: Digital Pressure Gauge
J 37287: Fuel Line Shut-off Adapter
For equivalent regional tools, refer to «Special Tools»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-special-tools-equipment) .

Ignition OFF, all accessories OFF, install a CH 48027: Gauge. Refer to «Fuel Pressure Gauge Installation and Removal»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Ignition ON, engine OFF, command the Fuel Pump Enable with a scan tool. Verify the fuel pressure is between 276-448 kPa (40-65 psi) and does not decrease more than 34 kPa (5 psi) in 1 min.
Engine idling at normal operating temperature, verify the scan tool Fuel Pump Control Module Fuel Pressure Sensor parameter is between 297-400 kPa (43-58 psi).
High fuel pressure readings may result due to hot soak fuel boiling. With the engine OFF, the fuel pressure may increase to the setting of the pressure relief regulator valve, approximately 580 kPa (84 psi).

Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool and observe the fuel pressure gauge while the fuel pump is operating. Verify the fuel pressure is between 276-448 kPa (40-65 psi). If the fuel pressure is greater than the specified range test for a restriction in the return side of the fuel filter. If the fuel filter tests normal, replace the primary fuel tank module. If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Restricted or plugged fuel filter Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 min. If the fuel pressure decreases more than the specified value, perform the following procedure: Ignition OFF, relieve the fuel pressure. Refer to «Fuel Pressure Relief»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-pressure-relief) . Install the J 37287: Adapter between the chassis fuel feed hose and the engine compartment fuel feed pipe. Open the valve on the J 37287: Adapter. Ignition ON, command the Fuel Pump Enable ON with a scan tool and bleed the air from the CH 48027: Gauge. Command the Fuel Pump Enable ON and then OFF with a scan tool. Close the valve on the J 37287: Adapter. Monitor the fuel pressure for 1 min. If the fuel pressure decreases more than 34 kPa (5 psi) within the specified time, locate and replace the leaking fuel injector(s). If the fuel pressure does not decrease more than 34 kPa (5 psi) within the specified time, replace the primary fuel tank module.
Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 min. If the fuel pressure decreases more than the specified value, replace the primary fuel tank module.
Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027: Gauge. The fuel pressure should not drop off during acceleration, cruise or hard cornering. If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Restricted or plugged fuel filter Inspect the harness connectors and the ground circuits of the fuel pump for poor connections
If the fuel system tests normal, refer to «Symptoms - Engine Controls (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Filter Replacement (China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Line Replacement - Chassis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Primary Fuel Tank Module Replacement (China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

An electric turbine style fuel pump attaches to the primary fuel tank module inside the fuel tank. The fuel pump supplies fuel through the fuel filter, contained in the fuel tank module, and the fuel feed pipe to the fuel injection system. The primary fuel tank module contains a reverse flow check valve. The check valve maintains fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.

Description and Operation

Fuel System Description (LAU or LY7)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

CH 48027: Digital Pressure Gauge
J 37287: Fuel Line Shut-off Adapter

Ignition OFF, all accessories OFF, install a CH 48027: Gauge. Refer to «Fuel Pressure Gauge Installation and Removal»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool. Verify the fuel pressure is between 276-448 kPa (40-65 psi) and does not decrease more than 34 kPa (5 psi) in 1 min.
Engine idling at normal operating temperature, verify the scan tool Fuel Pump Control Module Fuel Pressure Sensor parameter is between 297-400 kPa (43-58 psi).

Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool and observe the fuel pressure gauge while the fuel pump is operating. Verify the fuel pressure is between 276-448 kPa (40-65 psi). If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 min. If the fuel pressure decreases more than the specified value, perform the following procedure: Ignition OFF, relieve the fuel pressure. Refer to «Fuel Pressure Relief»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-pressure-relief) . Install the J 37287: Adapter between the chassis fuel feed hose and the engine compartment fuel feed pipe. Open the valve on the J 37287: Adapter. Ignition ON, command the Fuel Pump Enable ON with a scan tool and bleed the air from the CH 48027: Gauge. Command the Fuel Pump Enable ON and then OFF with a scan tool. Close the valve on the J 37287: Adapter. Monitor the fuel pressure for 1 min. If the fuel pressure decreases more than 34 kPa (5 psi) within the specified time, locate and replace the leaking fuel injector(s). If the fuel pressure does not decrease more than 34 kPa (5 psi) within the specified time, replace the primary fuel tank module.
Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 min. If the fuel pressure decreases more than the specified value, replace the primary fuel tank module.
Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027: Gauge. The fuel pressure should not drop off during acceleration, cruise or hard cornering. If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the primary fuel tank module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections
If the fuel system tests normal, refer to «Symptoms - Engine Controls (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Line Replacement - Chassis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Primary Fuel Tank Module Replacement (China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The control module enables the appropriate fuel injector pulse for each cylinder. The ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. A fuel injector control circuit DTC may not set, but a misfire may be apparent. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

Schematic Reference

Engine Controls Schematics (LAU) .

Connector End View Reference

«Component Connector End Views»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index)
«Inline Harness Connector End Views»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views-x100-through-x801)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Component Testing

Verify the resistance of each fuel injector with one of the following methods

If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each fuel injector should be 11-14 ohms. If the injectors measure OK, perform the Fuel Injector Balance Test. Refer to «Fuel Injector Balance Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . If not within the specified range, replace the fuel injector.
If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3 ohms. If the difference is equal to or less than 3 ohms, perform the Fuel Injector Balance Test. Refer to «Fuel Injector Balance Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . If the difference is more than 3 ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies a separate high voltage supply circuit and a high voltage control circuit for each fuel injector. The injector high voltage supply circuit and the high voltage control circuit are both controlled by the ECM. The ECM energizes each fuel injector by grounding the control circuit. The ECM controls each fuel injector with 65 V. This is controlled by a boost capacitor in the ECM. During the 65 V boost phase, the capacitor is discharged through an injector, allowing for initial injector opening. The injector is then held open with 12 V. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

Schematic Reference

Engine Controls Schematics (LF1)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Note. The resistance test must be performed at the fuel injector or mis-diagnosis will occur. The DMM and test leads must be calibrated to 0 ohms in order to prevent mis-diagnosis.

Test for 1.9-2.3 ohms at 20°C (68°F) between the high voltage supply circuit terminal 2 and the high voltage control circuit terminal 1 at the Q17 fuel injector. If not within the specified range, replace the Q17 fuel injector.
Measure the resistance between each terminal at the Q17 fuel injector and the Q17 fuel injector housing/case. The DMM should display OL ohms. If less than the specified value, replace the Q17 fuel injector.
If the injectors measure OK, perform the Fuel Injector Balance Test. Refer to «Fuel Injector Balance Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The CH-47976 Active Fuel Injector Tester (AFIT) is used to test the fuel pump, fuel system leak down, and the fuel injectors. See Special Tools . The on screen prompts or selections will indicate the steps required to perform each of the available tests. The tester will perform all of the tests automatically and display results of the test. The results can also be down loaded for storage and printing. Refer to the User Guide, CH 47976-11 for more information.

Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.

Schematic Reference

Engine Controls Schematics (LF1)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

CH-47976 Active Fuel Injector Tester (AFIT). See «Special Tools»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-special-tools-equipment) .
EL-39021-460 Fuel Injector Test Adapter. See «Special Tools»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-special-tools-equipment) .

Fuel Injector Balance Test with Special Tool

Ignition ON, verify that the scan tool engine coolant temperature (ECT) parameter is less than 94°C (201°F). If the ECT is greater than 94°C (201°F) allow the engine to cool before proceeding.
Turn OFF all accessories.
Turn OFF the ignition.
Install the AFIT. Refer to the AFIT User Guide.
Turn ON the AFIT and select the vehicle.
Turn ON the ignition and perform the Injector Test. If the AFIT aborts testing due to fuel pressure or fuel leak down, refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
View the test results. If any injector exceeds the recommended tolerance, replace the injector(s).

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

When performing the fuel injector balance test with the fuel injector tester or the scan tool, the scan tool is first used to energize the fuel pump relay. The fuel injector tester or the scan tool is then used to pulse each injector for a precise amount of time, allowing a measured amount of fuel to be injected. This causes a drop in the system fuel pressure that can be recorded and used to compare each injector.

The Active Fuel Injector Tester, CH 47976, is used to test the fuel pump, fuel system leak down, and the fuel injectors. Following the User Guide, CH 47976-11, and the on screen prompts or selections, will indicate the steps required to perform each of the available tests. The tester will perform all of the tests automatically and display results of the test. The results can also be down loaded for storage and printing.

Monitoring the Current Misfire Counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.

Schematic Reference

Engine Controls Schematics (LAU) .

Connector End View Reference

«Component Connector End Views»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-component-connector-end-views-index)
«Inline Harness Connector End Views»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-inline-harness-connector-end-views-x100-through-x801)

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

CH 47976: Active Fuel Injector Tester
CH 47976-60: J-Tool Adapter
CH 48027: Digital Pressure Gauge
EL 39021-460: Fuel Injector Test Adapter
J 39021: Fuel Injector Coil and Balance Tester
J 39021-210: Injector Tester Adapter Box

Note. DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). Irregular fuel pressure readings may result due to hot soak fuel boiling. Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. Before proceeding with this test review the User Manual CH 48027-5 for Safety Information and Instructions.

Fuel Injector Balance Test-Fuel Pressure Test

Install a fuel pressure gauge. Refer to «Fuel Pressure Gauge Installation and Removal»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
Turn ON the ignition, with the engine OFF.
Command the fuel pump relay ON with a scan tool.
Observe the fuel pressure gauge with the fuel pump commanded ON. The fuel pressure should be 345-414 kPa (50-60 psi). If the fuel pressure is not within the specified range, refer to «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Monitor the fuel pressure gauge for one minute. The fuel pressure should not decrease more than 34 kPa (5 psi). If the fuel pressure decreases more than 34 kPa (5 psi), refer to «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Perform the Fuel Injector Balance Test with Special Tool, the Fuel Injector Balance Test with Tech 2, or the Fuel Injector Balance Test with the Active Fuel Injector Tester.

Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 A position.
Disconnect the multi-way harness connector of the fuel injectors.
Connect the J 39021: Fuel Injector Coil and Balance Tester, the J 39021-210: Injector Tester Adapter Box, and the EL 39021-460: Fuel Injector Test Adapter to the fuel injector multi-way harness connector.
Command the fuel pump relay ON and then OFF three times with a scan tool. On the last command, as the fuel pressure begins to slowly degrade and stabilize, select a fuel pressure within 34 kPa (5 psi) of the maximum pump pressure. Record this fuel pressure. This is the starting pressure at which you will pulse each injector.
Command the fuel pump relay ON one more time and energize the fuel injector by depressing the Push to Start Test button on the J 39021: Fuel Injector Coil and Balance Tester at the previously selected pressure.
After the injector stops pulsing, select Min from the Display Mode on the CH 48027: Gauge and record the Min pressure.
Clear the Min/Max results on the CH 48027: Gauge.
Select Normal from the Display Mode on the CH 48027: Gauge.
Repeat steps 5 through 8 for each fuel injector.
Subtract the minimum pressure from the starting pressure for one fuel injector. The result is the pressure drop value.
Obtain a pressure drop value for each fuel injector.
Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 psi). If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 psi), replace the fuel injector.

Fuel Injector Balance Test with Tech 2

Command the fuel pump relay ON and then OFF three times with a scan tool. On the last command, as the fuel pressure begins to slowly degrade and stabilize, select a fuel pressure within 34 kPa (5 psi) of the maximum pump pressure. Record this fuel pressure. This is the starting pressure at which you will pulse each injector.
With a scan tool, select the Fuel Injector Balance Test function within the Special Functions menu.
Select an injector to be tested.
Press Enter to prime the fuel system.
Energize the fuel injector by depressing the Pulse Injector button on the scan tool at the previously selected pressure.
After the injector stops pulsing, select Min from the Display Mode on the CH 48027: Gauge and record the Min pressure.
Clear the Min/Max results on the CH 48027: Gauge.
Select Normal from the Display Mode on the CH 48027: Gauge.
Press Enter on the scan tool to bring you back to the Select Injector screen.
Repeat steps 3 through 9 for each fuel injector.
Subtract the minimum pressure from the starting pressure for one fuel injector. The result is the pressure drop value.
Obtain a pressure drop value for each fuel injector.
Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 psi). If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 psi), replace the fuel injector.

Fuel Injector Balance Test with the Active Fuel Injector Tester

Turn OFF all accessories.
Turn OFF the ignition.
Install the Active Fuel Injector Tester. Refer to the Active Fuel Injector Tester User Guide.
Turn ON the Active Fuel Injector Tester and select the vehicle.
Turn ON the ignition and perform the Injector Test. If the Active Fuel Injector Tester aborts testing due to fuel pressure or fuel leak down, refer to «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
View the test results. If any injector exceeds the recommended tolerance, replace the injector(s).

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The fuel injector balance test is performed while the engine is running at idle. The scan tool pressurizes the fuel rail to a predetermined pressure before each injector is pulsed for a precise amount of time allowing a measured amount of the fuel to be injected. This causes a drop in the system fuel pressure that is recorded and used to compare each injector.

Monitoring the Current Misfire Counters may help to isolate the fuel injector that is causing the condition.
Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.

Note. DO NOT perform this test if the engine coolant temperature (ECT) is above 60°C (140°F). Irregular fuel pressure readings may result due to hot soak fuel boiling. Verify that adequate fuel is in the fuel tank and that the battery is fully charged before proceeding with this diagnostic. It may be necessary to install a battery charger.

Fuel Injector Balance Test

Verify the correct low side fuel pressure. Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Engine running at normal operating temperature. With a scan tool, select the Fuel Injector Balance function within the Output Controls menu.
Select and test an injector. Repeat for each injector in order to obtain a pressure drop value for each injector.
After all injectors are tested, record the fuel pressure drops.
Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop.
Multiply the average pressure drop by 0.20. This is the acceptable variance from the average pressure drop, 20 percent. If the difference between any individual pressure drop and the average pressure drop is more than the acceptable variance, replace the fuel injector.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Description

Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system, and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust or deterioration.

Ethanol concentrations of greater than 10 percent can cause driveability conditions and fuel system deterioration. Fuel with greater than 10 percent ethanol could result in driveability conditions such as hesitation, lack of power, stalling, or no start. Excessive concentrations of ethanol used in vehicles not designed for it may cause fuel system corrosion, deterioration of rubber components, and fuel filter restriction.

Test Procedure

Test the fuel composition using J 44175 Fuel Composition Tester and J44175-3 Instruction Manual. See «Special Tools»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-special-tools-equipment) .
If water appears in the fuel sample clean the fuel system, refer to «Fuel System Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-system-cleaning) .
Subtract 50 from the reading on the DMM in order to obtain the percentage of alcohol in the fuel sample. Refer to the examples in the Fuel Composition Test Examples table.
If the fuel sample contains greater than 15 percent ethanol, add fresh, regular gasoline to the vehicle's fuel tank.
Test the fuel composition.
If testing shows the ethanol percentage is still greater than 15 percent, replace the fuel in the vehicle. Refer to «Fuel Tank Draining»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .

	Frequency (Hz)	Subtract 50	Ethanol Percent
Example A	50 Hz	50	0
Example B	65 Hz	50	15
Example C	129 Hz	50	79

Fuel Composition Test Examples

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel rail, and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust, or deterioration.

Alcohol concentrations greater than 10 percent in the fuel can be detrimental to fuel system components. Alcohol contamination may cause fuel system corrosion, deterioration of rubber components, and subsequent fuel filter restriction. Fuel contaminated with alcohol may cause driveability conditions such as hesitation, lack of power, stalling, or no start. Some types of alcohol are more detrimental to fuel system components than others.

Alcohol in Fuel Testing Procedure

The fuel sample should be drawn from the bottom of the tank so that any water present in the tank will be detected. The sample should be bright and clear. If alcohol contamination is suspected then use the following procedure to test the fuel quality.

Using a 100 ml (3.38 oz.) specified cylinder with 1 ml (0.34 oz.) graduation marks, fill the cylinder with fuel to the 90 ml (3.04 oz.) mark.
Add 10 ml (0.34 oz.) of water in order to bring the total fluid volume to 100 ml (3.38 oz.) and install a stopper.
Shake the cylinder vigorously for 10-15 seconds.
Carefully loosen the stopper in order to release the pressure.
Re-install the stopper and shake the cylinder vigorously again for 10-15 seconds.
Put the cylinder on a level surface for approximately 5 minutes in order to allow adequate liquid separation.

If alcohol is present in the fuel, the volume of the lower layer, that now contains both alcohol and water, will be greater than 10 ml (0.37 oz.). For example, if the volume of the lower layer is increased to 15 ml (0.51 oz.), this indicates at least 5 percent alcohol in the fuel. The actual amount of alcohol may be somewhat more because this procedure does not extract all of the alcohol from the fuel.

Particulate Contaminants in Fuel Testing Procedure

The fuel sample should be drawn from the bottom of the tank so that any contaminants present in the tank will be detected. The sample should be bright and clear. If the sample appears cloudy or contaminated with water as indicated by a water layer at the bottom of the sample, use the following procedure to diagnose the fuel.

Using an approved fuel container, draw approximately 0.5 liter (0.53 qt) of fuel.
Place the cylinder on a level surface for approximately 5 minutes in order to allow settling of the particulate contamination.

Particulate contamination will show up in various shapes and colors. Sand will typically be identified by a white or light brown crystals. Rubber will appear as black and irregular particles. If particles are found, clean the entire fuel system thoroughly. Refer to Fuel System Cleaning .

Vehicle Setup

Engine OFF, open the hood. Position a large fan to blow air under the vehicle onto the fuel tank area.
Connect the red battery clip from the tester to the positive battery terminal.
Connect the black battery clip from the tester to chassis ground.

Flowmeter Test - Leak Detection

Open the Nitrogen tank valve and turn the NITROGEN/SMOKE valve on the front control panel to NITROGEN.
Connect the hose to the correct test orifice on the bottom front of the tester. For orifice size, refer to the GM Service manual for the vehicle being tested. The vehicle specific information can be found in service procedures for DTCs that relate to evaporative emission (EVAP) system leaks.
Press and release the remote switch to activate the tester.
Position the sliding red flag on the flowmeter to align with the floating indicator. When the red flag is set, press and release the remote switch to deactivate the tester.
Remove the hose from the test orifice and install the hose onto the vehicle. For proper connection location, and the special tool numbers for any adapters that may be required, refer to the service procedures for DTCs that relate to EVAP system leaks.
Ignition ON, seal the EVAP system per instructions in the service procedures for DTCs that relate to EVAP system leaks. Most systems can be sealed using a scan tool output control for the EVAP canister vent solenoid valve, other systems require that the vent system be plugged.
Press and release the remote switch to activate the nitrogen flow and fill the system.
Compare the stable floating indicator position to the red flag. ABOVE the red flag, the result is UNACCEPTABLE, FAIL - Go to «Smoke Procedure - Locate the Leak»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis__smoke-procedure-locate-the-leak) BELOW the red flag, the result is ACCEPTABLE, PASS - Test complete
Press and release the remote switch to deactivate the tester.

Smoke Procedure - Locate the Leak

Turn OFF any fans that may cause air movement around or near the vehicle.
Connect the nitrogen/smoke hose to the vehicle as directed in the service procedures. Some vehicles require that the nitrogen/smoke hose be connected at the front of the EVAP system at the EVAP service port. An adapter may be necessary. Other vehicles require the connection be made at the rear of the system using an adapter at the fuel fill cap. Consult the service procedures for DTCs that relate to evaporative emission (EVAP) system leaks for vehicle specific instructions regarding connection location and adapters.
Open the nitrogen tank valve and turn the NITROGEN/SMOKE valve on the control panel to SMOKE.
Press and release the remote switch to activate the tester and inject smoke into the EVAP system.
Verify smoke has filled the EVAP system by opening the system opposite the end where smoke is injected. When injecting smoke at the service port, remove the fuel fill cap, or temporarily leave the EVAP canister vent valve open, until smoke is observed. Then close the system and continue testing. If using a special tool fuel fill cap adapter at the filler neck, vent the system at the service port until smoke is observed then close the system to continue with the test.
Press and release the remote switch to deactivate the tester.
Introduce smoke into the system for an additional 60 seconds. Continue introducing smoke at 15-second intervals, as necessary.
Using the a high-intensity white light, inspect the entire EVAP system path, and look for the source of the leak indicated by the exiting smoke. Introduce smoke at 15-second intervals, as needed, until leak source is identified.

The Concern

Ideal circumstances for conducting the EVAP Flowmeter Test require equal temperatures between the nitrogen gas and the vehicle EVAP system. Significant differences in temperature between them can result in a flow or pressure change during testing, causing misleading results. Typically, the Evaporative Emissions System Tester is stored indoors, approximately 21°C (70°F). Vehicles brought in for diagnosis may have an EVAP system at significantly different temperatures -40 to +43°C (-40 to +110°F).

For Example

Note. With no temperature difference between the nitrogen gas and EVAP system, the resulting vehicle EVAP system pressure will remain stable at 13 inches H2O once pressurized, providing no leaks are present.

When the EVAP Flowmeter Tests are performed with significant differences in temperature between the nitrogen gas and the vehicle EVAP system, the following results can occur

An increase in flow during the flowmeter test can be caused by a vehicle's warm EVAP system cooling down.
A decrease in flow during the flowmeter test can be caused by a vehicle's cool EVAP system warming up.

The Solution

When working on a vehicle with significant temperature differences between the vehicle EVAP system and the nitrogen gas, allow the vehicle EVAP system temperature to stabilize as close as possible to the temperature of the nitrogen gas before conducting the Flowmeter Test.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ignition system on this engine uses individual ignition coils and ignition control circuits for each cylinder. Ignition voltage is supplied to each bank of ignition coils. The engine control module (ECM) controls the ignition system operation. The ECM controls each coil using the ignition control circuits. The ECM commands the ignition control circuit low when a spark event is requested. The sequencing and timing are controlled by the ECM.

The ignition coils for each bank are fused separately. If a fuse opens or the ignition voltage circuit opens between the fuse and the splice, all the ignition coils for one bank of the engine would be inoperative. If the ground circuit opens at the engine block, the ignition coils would be inoperative for one bank of the engine.
Inspect the ignition coils for aftermarket devices. An aftermarket device connected to the ignition coil circuits, may cause a condition with the ignition coils.

Schematic Reference

Engine Controls Schematics (LAU) or Engine Controls Schematics (LF1)

Connector End View Reference

Component Connector End Views

Description and Operation

Electronic Ignition System Description

Electrical Information Reference

«Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL 26792: Spark Tester
For equivalent regional tools, refer to «Special Tools»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-special-tools-equipment) .

Ignition OFF, disconnect the harness connector of the affected T8 ignition coil.
Ignition ON, test for battery voltage between the ignition voltage circuit terminal D or 2 and ground. If less than B+, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition voltage circuit and replace as necessary.
Crank or start the engine. Test for 200-400 mV between the appropriate ignition control circuit terminal C or 1 and ground. If less than the specified value, test the ignition control circuit for a short to ground or an open/high resistance. If the circuit/connection tests normal, replace the K20 ECM. If greater than the specified value, test the ignition control circuit for a short to voltage. If the circuit/connection tests normal, replace the K20 ECM.
Ignition OFF, all vehicle systems OFF, this may take up to 2 min, test for less than 5 ohms between the low reference circuit terminal B or 3 and the K20 ECM housing. If greater than the specified value, test for an open/high resistance in the low reference circuit. If the circuit/connection tests normal, replace the K20 ECM.
Test for less than 5 ohms between the ground circuit terminal A or 4 and ground. If greater than the specified value, test for an open, or high resistance in the ground circuit.
Remove the T8 ignition coil from the engine. Connect the harness.
Remove the fuse for the fuel pump or the fuel pump control module, if equipped.
Crank the engine and test for strong spark using the EL 26792: Tester. If no spark or weak spark is observed, replace the T8 ignition coil.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Ignition Coil Replacement - Bank 1»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Ignition Coil Replacement - Bank 2»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
«Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Several states require that a vehicle pass on-board diagnostic (OBD) system tests and the inspection/maintenance (I/M) emission inspection in order to renew license plates. This is accomplished by viewing the I/M System Status display on a scan tool. Using a scan tool, the technician can observe the I/M System Status in order to verify that the vehicle meets the criteria that complies with the local area requirements. While testing in the I/M System Status mode, some DTCs may occur that are called I/M Test DTCs. An I/M Test DTC is defined as a fault code that is currently commanding the MIL ON, and is stored in non-volatile memory. The intended use of this data is to prevent vehicles from passing I/M inspection without proper repair to the vehicle. These fault codes are not erasable from any scan tool command or erasable by disconnecting power to the controller. The I/M Test DTCs will be supported by all emissions related ECUs such as ECMs, TCMs, FPCMs, etc. An I/M Test DTC will not be stored or erased from the ECU except at the end of trip processing which occurs 5 s after ignition OFF.

Conditions for Updating the I/M System Status

Each system requires at least one, and sometimes several, diagnostic tests. The results of these tests are reported by a diagnostic trouble code (DTC). A system monitor is complete when either all of the DTCs comprising the monitor have Run and Passed, or any one of the DTCs comprising the monitor have illuminated the malfunction indicator lamp (MIL). Once all of the tests are completed, the I/M System Status display will indicate YES in the Completed column.

For example, when the HO2S Heater Status indicates YES, either all of the oxygen sensor heater tests have passed or one of the tests has illuminated the MIL. If the vehicle has four heated oxygen sensors, either all four heater circuit tests have passed or one of the heater circuit tests has illuminated the MIL. The I/M System Status will indicate NO under the Completed column when any of the required tests for that system have not run. The following is a list of conditions that would set the I/M System Status indicator to NO

The vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
The battery has been disconnected or discharged below operating voltage.
The control module power or ground has been interrupted.
The control module has been reprogrammed.
The control module DTCs have been cleared as part of a service procedure.

Conditions for Clearing I/M Test DTCs

Only the OBD II System can erase the I/M Test DTC. The OBD II system must determine that the malfunction that caused the I/M Test DTC to be stored is no longer present and is not commanding the MIL. Each of the following represents ways to clear an I/M Test DTC: If the MIL goes out due to 3 passing drive cycles, scan tool code clear is not used, the I/M Test DTC is erased at power down of the last drive cycle. If a scan tool code clear is used to turn OFF the MIL, the I/M Test DTC is not erased, the DTC must PASS and not FAIL. The I/M Test DTC is erased at power down of the drive cycle. If the controller is reflashed/reprogrammed, all I/M Test DTCs are erased.
For the OBD II System to run a single drive cycle for clearing an I/M Test DTC, all of the following conditions must occur: Cumulative time of engine run time is greater than 600 s. Cumulative vehicle operation above 41 kPa (25 mph) for over 300 s. Continuous vehicle idle for greater than 30 s. Turn ignition OFF for 5 s and allow the code to clear.

Monitored Emission Control Systems

The OBD II system monitors all emission control systems that are on-board. Not all vehicles need every possible emission control system. For example, a vehicle may not be equipped with secondary air injection (AIR) or exhaust gas recirculation (EGR). The OBD II regulations require monitoring of the following; if equipped

The air conditioning system
The catalytic converter efficiency
Comprehensive component monitoring - Emission related inputs and outputs
The evaporative emission (EVAP) system
The fuel delivery system
Heated catalyst monitoring
Misfire monitoring
The oxygen sensor system (O2S or HO2S)
The oxygen sensor heater system (HO2S heater)

For the specific DTCs required for each system, refer to Inspection/Maintenance (I/M) Test DTC Table . Systems such as misfire and comprehensive components may not be listed in a system status list. These tests run continuously and do not require an I/M System Status indicator.

The I/M System Status display provides an indication of when the control module has completed the required tests. This does not necessarily mean that the test has passed, only that a decision was made. If the diagnostic fails, a DTC will indicate the failure. If a failure indication is present for a DTC associated with one of the I/M regulated systems, it may prevent other required tests from running. For example, a DTC for the control circuit of the EVAP purge solenoid may not be listed in the Inspection/Maintenance System DTC Table because it is a continuous test. If this DTC is set, the Active Tests for the EVAP system may not run.

The I/M System Status information may be useful for a technician to determine if diagnostics have run when verifying repairs.

Review the I/M System Status indicators. All I/M System Status indicators should report YES, and no I/M Test DTCs should be present.

Observe the Engine DTC information with a scan tool. Verify no DTCs are present. If a DTC is set that would prevent the I/M System Status tests from completing, diagnose that DTC before continuing. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Review applicable service bulletins for software updates that would prevent the I/M System Status tests from completing. If a control module re-program or other repair is required, perform the «Inspection/Maintenance Complete System Set Procedure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Observe the I/M System Status indicators. If any I/M System Status indicators report NO, perform the «Inspection/Maintenance Complete System Set Procedure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Observe the I/M Test DTC information with a scan tool. Verify there are no I/M Test DTCs present. If an I/M Test DTC is set and all of the I/M System Status indicators are Yes, there is no need to perform the Complete System Set Procedure. Diagnose the DTC using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) and refer to Conditions for Clearing the I/M Test DTCs. If an I/M Test DTC is set and the I/M System Status indicators are NO, diagnosis the DTC and perform the «Inspection/Maintenance Complete System Set Procedure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .

Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The purpose of the Inspection/Maintenance (I/M) complete system set procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics and complete the trips for those particular diagnostics. When all I/M monitored diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform the Inspection/Maintenance (I/M) Complete System Set Procedure if any I/M System Status indicators are set to NO.

Conditions for Meeting a Cold Start

The ignition voltage between 10 and 15 V.
The barometric pressure (BARO) is more than 75 kPa (10.9 psi).
The engine coolant temperature (ECT) at start-up is less than 42°C (108°F).
The intake air temperature (IAT) is between 2-32°C (36-90°F).
The engine is OFF for greater than 6 hours or the following conditions must be met: The start-up IAT minus start-up ECT are within 12°C (22°F). The start-up ECT minus start-up IAT are within 50°C (90°F).
Fuel level is between 25 and 75 %.

Review the Inspection/Maintenance (I/M) System Status indicators. All I/M System Status indicators should report YES, and no I/M Test DTCs should be present.

Inspection/Maintenance (I/M) System Set Procedure

Ensure that the vehicle meets the conditions for a cold start listed above. If the EVAP I/M System Status indicator displays NO, perform the EVAP Service bay test if applicable.
Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc., and open the hood.
Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
Start and idle the engine for 2 min.
Close the hood, release the parking brake and Accelerate at part throttle to 72-80 km/h (45-50 mph) with this speed maintained until the engine reaches operating temperature, 8-10 min.
Continue operation under these conditions for an additional 6 min.
Accelerate at part throttle to 90 km/h (55 mph) with this speed maintained for 2 min.
Release the accelerator pedal for at least 10 s. This will allow the vehicle to enter the decel fuel cut off.
Safely stop the vehicle, with the engine in drive for automatic or neutral with the clutch pedal depressed and parking brake applied for manual. Allow the vehicle to idle for 2 min.
Shift the vehicle to park for automatic and neutral for manual. Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 45 min.
Observe the Inspection/Maintenance (I/M) System Status with a scan tool. All of the I/M System Status indicators should display YES. If the EVAP I/M System Status indicator displays NO, turn OFF the ignition, ensure that the vehicle meets the conditions for a cold start, and repeat steps 6-11 three more times, or until the EVAP I/M System Status indicator transitions to YES. If the indicator continues to display NO, refer to the «Inspection/Maintenance (I/M) Test DTC Table»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis__inspectionmaintenance-im-test-dtc-table) to identify the DTCs that did not run. If any of the I/M System Status indicators display NO, refer to the «Inspection/Maintenance (I/M) Test DTC Table»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis__inspectionmaintenance-im-test-dtc-table) for the indicator which did not display YES. The I/M System DTC Table identifies the DTCs associated with each I/M System Status Indicator.
Observe the I/M Test DTC information with a scan tool. Verify there are no I/M Test DTCs present. If an I/M Test DTC is set, diagnose the DTC using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) and refer to «Inspection/Maintenance System Check»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
Observe the engine DTC information with a scan tool. Verify no DTCs are present. If a DTC is set, diagnose using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . After repairs, perform the «Inspection/Maintenance Complete System Set Procedure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) to verify no further DTCs are set.

Inspection/Maintenance (I/M) Test DTC Table

System	DTCs Required to Set System Status to YES
If an I/M System Status indicator did NOT update to YES during the Inspection/Maintenance Complete System Set Procedure , review each indicator and reference this table to determine each DTC associated with the I/M System Status Indicator. Each DTC listed below has specific conditions that must be met for the diagnostic to run. Included within the conditions are additional DTCs, which if set, may inhibit the DTCs listed below from running. Reviewing and operating the vehicle within the Conditions for Running for each DTC listed below will allow the I/M System Status Indicators to transition to YES.
Catalyst	DTC P0420 or P0430
EVAP	DTC P0442 DTC P0446 DTC P0450 or P0451 (LAU) for LAU DTC P0451-P0454 (LF1) for LF1 DTC P0455 or P0497 (LAU) for LAU DTC P0455 (LF1) for LF1 DTC P0496
Oxygen Sensor	DTC P0130 (Without LF1) for LAU DTC P0131, P0132, or P0134 (Without LF1) for LAU DTC P0133, P013A, or P013E (Without LF1) for LAU DTC P0137, P0138, or P0140 (Without LF1) for LAU DTC P2270 (Without LF1) for LAU DTC P2271 (Without LF1) for LAU DTC P0131, P0132, P0137, P0138, P0151, P0152, P0157, P0158, P2A00, P2A01, P2A03, or P2A04 (LF1) for LF1 DTC P0133, P013A-P013F, P014A, P014B, P0153, P1133, or P1153 (LF1) for LF1 DTC P0134, P0140, P0154, or P0160 (LF1) for LF1 DTC P2270 or P2272 (LF1) for LF1 DTC P2271 or P2273 (LF1) for LF1
Oxygen Sensor Heater	DTC P0030, P0031, P0032, P0036, P0037, or P0038 (Without LF1) for LAU DTC P0135 or P0141 (Without LF1) for LAU DTC P0030, P0036, P0050, P0053, P0054, P0056, P0059, P0060, P0135, P0141, P0155, or P0161 (LF1) for LF1
Camshaft System	DTC P000A-P000D, P0011, P0014, P0021, or P0024 (Without LF1, LFW) for LAU DTC P0011, P0014, P0021, or P0024 (LF1, LFW) for LF1
AIR	DTC P2431-P2433 for LAU DTC P0418, P2257, or P2258 for LAU DTC P0411 for LAU

Engine Control System & Fuel System - 2.8l, 3.0l - Symptom Troubleshooting and Diagnosis Cadillac SRX II

Diagnostic Instructions

Symptoms Description

Symptoms Verification

Identifying Intermittent Conditions

Visual/Physical Check

Backfire, Cuts Out/Misses, Detonation/Spark Knock, Dieseling/Run-On, Hard Start, Hesitation/Sag/Stumble, Lack of Power/Sluggishness/Sponginess, Poor Fuel Economy, Rough, Unstable, or Incorrect Idle and Stalling, or Surges/Chuggles

Hard Start

Hesitation, Sag, Stumble

Poor Fuel Economy

Detonation spark Knock

Lack of Power, Hesitation, or Cut Out

Rough, Unstable, or Incorrect Idle and Stalling

Surges/Chuggles

Fuel Odor

ECM Commanded Reduced Engine Power

Detonation/Spark Knock

Poor Fuel Fill Quality

Circuit/System Description

Diagnostic Aids

Reference Information

Circuit/System Verification

Circuit/System Testing

Repair Procedures

Diagnostic Fault Information

Component Testing

Fuel Injector Balance Test with Special Tool

Fuel Injector Balance Test-Fuel Pressure Test

Fuel Injector Balance Test with Tech 2

Fuel Injector Balance Test with the Active Fuel Injector Tester

Fuel Injector Balance Test

Description

Test Procedure

Alcohol in Fuel Testing Procedure

Particulate Contaminants in Fuel Testing Procedure

Vehicle Setup

Flowmeter Test - Leak Detection

Smoke Procedure - Locate the Leak

The Concern

For Example

The Solution

Conditions for Updating the I/M System Status

Conditions for Clearing I/M Test DTCs

Monitored Emission Control Systems

Conditions for Meeting a Cold Start

Inspection/Maintenance (I/M) System Set Procedure

Inspection/Maintenance (I/M) Test DTC Table

More articles — Engine Performance

Login / Signup

Enter the code

You have successfully logged in!