Engine Controls and Fuel - 3.6l - Troubleshooting & Diagnosis Cadillac STS I рестайлинг

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Symptoms Description

Driveability symptoms do not set DTCs. The driveability symptoms are defined below. Certain conditions can cause multiple symptoms. These conditions are listed together. Additional conditions that may only cause certain symptoms are listed separately. Perform the Symptoms Testing before using the Additional Symptoms Tests.

Symptoms Verification

1. The engine control module (ECM) and the malfunction indicator lamp (MIL) are operating correctly.
2. There are no DTCs stored.
3. The scan tool data is within the normal operating range.
4. Bulletins are not available for the current symptom.
5. The ECM grounds are clean, tight, and in the correct locations.
6. The vehicle tires are correctly inflated and meet original equipment specifications.
7. The air filter element is not restricted.

Symptoms Testing

1. Test for the following conditions: The fuel system for the following: Correct fuel pressure-Refer to «Fuel System Diagnosis»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) . Fuel injectors that are leaking or improper operation-Refer to «Fuel Injector Solenoid Coil Test (w/LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) . Contaminated or a poor fuel quality condition-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (w/o Special Tool)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) . The ignition system for the following: Spark plugs for incorrect heat range or an abnormal condition-Refer to «Spark Plug Inspection»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . For diagnosis of coolant or oil fouled spark plugs-Refer to «Loss of Coolant (LH2, LY7, LLT)»(/cadillac/sts/i-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant-lh2-ly7-llt) or «Oil Consumption Diagnosis»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-1-of-6__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 (EI) System Diagnosis (w/LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) . The operation of the transmission torque converter clutch (TCC)-The scan tool should indicate an engine speed drop when the TCC is commanded ON. The operation of the A/C compressor Items that can cause an engine to run lean or rich-Refer to «DTC P2178, P2180, P2188, or P2190»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-dtc-p0856-to-dtc-p2636) . The crankshaft position (CKP) sensor for the correct resistance-The CKP sensor resistance may be out of range after a hot soak. The resistance should be between 700-1200 ohms. The engine for the following mechanical failures-Refer to «Symptoms - Engine Mechanical»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-1-of-6) . Excessive oil in the combustion chamber or leaking valve seals Incorrect cylinder compression Sticking or leaking valves Worn camshaft lobes Incorrect valve timing 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 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-Refer to «Knock Sensor (KS) System Description»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__knock-sensor-ks-system-description) and «DTC P0326, P0327, P0328, P0331, P0332, or P0333»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-dtc-p0201-to-dtc-p0700) . 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/sts/i-2007-2011/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. Inspect the positive crankcase ventilation (PCV) system and all connections for leaks or restrictions. 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/sts/i-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system) . Proper engine coolant level-Refer to «Cooling System Draining and Filling (GE 47716)»(/cadillac/sts/i-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill)»(/cadillac/sts/i-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system) .
2. If the above conditions do not address the symptom, refer to the «Additional Symptoms Tests»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis__additional-symptoms-tests) .

Additional Symptoms Tests

Hard Start

1. 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/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__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»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . If the sensor is within the specification, test the ECT circuits for a high resistance.
2. Test the fuel pump relay operation. The fuel pump should turn ON for 2 seconds when the ignition is turned ON. Refer to «Fuel Pump Electrical Circuit Diagnosis»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .

Hesitation, Sag, Stumble

1. Test the fuel pressure. Refer to «Fuel System Diagnosis»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
2. Test the generator. Refer to «Symptoms - Engine Electrical»(/cadillac/sts/i-2007-2011/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.

Poor Fuel Economy

1. Heavy loads being carried or towed
2. Acceleration rate too much or too often
3. Inspect for foreign material accumulation in the throttle bore, and for carbon deposits on the throttle plate and shaft. Also inspect for throttle body tampering.

Poor Fuel Fill Quality

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

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

Diagnostic Aids

Inspect for any of the following conditions

1. 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.
2. 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.
3. 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.
4. 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 (w/LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
5. 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.
6. Inspect the engine for good secure electrical grounds.
7. 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 minutes 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.
8. 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.

Reference Information

Schematic Reference

Engine Controls Schematics

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. CH-48027 Digital Pressure Gage. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. J 26792 Spark Tester. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

Circuit/System Verification

1. Crank or start the engine. Observe the DTC information with a scan tool. Verify that DTCs P0116, P0118, P0119, P0201-P0206, P0335, P0336, P0337, P0338, P0351-P0356, P0601, P0602, P0604, P0606, P0627, P0628, P0629, P1629, P1631, P1632, or P2105 do not set. If any of the listed DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-trouble-code-dtc-list) .
2. Ignition ON, observe the Theft Deterrent parameter with a scan tool. The parameter should display Disabled. If Enabled is displayed, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-trouble-code-dtc-list) .
3. Test the ignition system for spark. Refer to «Electronic Ignition (EI) System Diagnosis (w/LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
4. Ignition ON, command the fuel pump ON with a scan tool. You should hear the fuel pump turn ON. If the fuel pump does not turn ON, refer to «Fuel Pump Electrical Circuit Diagnosis»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
5. Ignition OFF, install the CH-48027 . See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
6. Ignition ON, command the fuel pump ON with a scan tool. The fuel pressure should be between 380-410 kPa (55-60 psi). If the fuel pressure is not within range, refer to «Fuel System Diagnosis»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
7. Verify that the following conditions do not exist: Disconnect the MAF sensor. The engine control module (ECM) will ignore the MAF sensor and default to the calculated air flow. If disconnecting the MAF sensor corrects the condition and the connections are OK, replace the MAF sensor. Refer to «Mass Airflow Sensor/Intake Air Temperature Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
8. Collapsed air intake duct to the throttle body
9. Restricted air filter element
10. Spark plugs for being gas or coolant fouled-Refer to «Spark Plug Inspection»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
11. A skewed engine coolant temperature (ECT) sensor-Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__temperature-versus-resistance-engine-coolant) .
12. Exhaust system restricted-Refer to «Restricted Exhaust»(/cadillac/sts/i-2007-2011/remont/exhaust/#engine-exhaust-system) .
13. Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (w/o Special Tool)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
14. Engine mechanical condition, for example, worn timing chain and gears, low compression-Refer to «Symptoms - Engine Mechanical»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-1-of-6) .

1. If you find any of the above conditions, repair as necessary.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) provides ignition voltage to the coil side of the fuel pump relay whenever the engine is cranking or running. The control module enables the fuel pump relay as long as the engine is cranking or running, and ignition system reference pulses are received. If no ignition system reference pulses are received, the control module turns OFF the fuel pump. The fuel pump relay control circuit is equipped with a feedback circuit that is pulled up to 2.5 volts within the ECM. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

The following conditions may cause the fuel pump fuse to open

1. The fuse is faulty.
2. There is an intermittent short to ground in the supply voltage circuit of the fuel pump.
3. The fuel pump has an intermittent internal condition.

Schematic Reference

Engine Controls Schematics

Description and Operation

Fuel System Description (With LLT)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 43244 Relay Puller Pliers. See Special Tools .

1. Ignition ON, command the fuel pump relay ON with a scan tool. You should hear the fuel pump operate for 3-5 seconds and then turn OFF.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

Circuit/System Testing

1. Ignition OFF, the fuel pump should not be operating. If the fuel pump operates continuously, test for a short to voltage in supply voltage circuit of the fuel pump. If the circuit/connections test normal, replace the fuel pump relay.
2. Test the fuel pump fuse. The fuse should not be open. If the fuel pump fuse is open, test for a short to ground in the supply voltage circuit of the fuel pump. If the circuit/connections test normal, replace the fuel pump.
3. Ignition OFF, remove the fuel pump relay from the electrical center.
4. Ignition ON, test for battery voltage between the B+ voltage circuit of the fuel pump relay and ground. If less than B+, repair the B+ voltage circuit of the fuel pump relay for an open/high resistance.
5. Connect a 15A fused jumper wire between the B+ circuit of the fuel pump relay and the supply voltage circuit of the fuel pump. The fuel pump should operate. If the fuel pump does not operate, test for the following conditions: An open/high resistance in the supply voltage circuit of the fuel pump An open/high resistance in the ground circuit of the fuel pump If the above circuit/connections test normal, replace the fuel pump.
6. If all circuit/connections test normal, test or replace the fuel pump relay.

Component Testing

1. Measure for 135-185 ohms between terminals 85 and 86 of the fuel pump relay. If the resistance is not within the specified range, replace the fuel pump relay.
2. Measure for infinite resistance between the following terminals of the fuel pump relay: 30 and 86 30 and 87 30 and 85 85 and 87 If continuity is detected, replace the fuel pump relay.
3. Connect a 15A fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negative terminal of the battery to relay terminal 86. Measure for less than 2 ohms between terminals 30 and 87 of the relay. If the resistance measures more than 2 ohms, replace the fuel pump relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction)
2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.

The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the primary fuel tank module, eliminating the need for a return pipe from the engine. 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 tank module inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter, past the fuel pressure regulator, and through the fuel feed pipe to the fuel injection system. The fuel pressure regulator has a T-joint that diverts the needed fuel to the fuel rail with the unused fuel dropping back into the reservoir of the primary fuel tank module. The primary fuel tank module contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.

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.

1. A vehicle that runs out of fuel above empty may indicate a condition with the siphon jet pump, or transfer lines between the fuel tanks. Inspect for blockage, foreign objects or restrictions in all related hardware.
2. A vehicle that runs out of fuel above empty may be caused by an inaccurate fuel level sender. Inspect the float arm for binding, or obstructions.

Description and Operation

Fuel System Description (With LLT)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools Required

1. CH-48027 Fuel Pressure Gage. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. J 37287 Fuel Line Shut-Off Adapters. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Ignition ON, command the fuel pump relay ON with a scan tool. You should hear the fuel pump turn ON and OFF for 3-5 seconds. If the fuel pump does not operate, refer to «Fuel Pump Electrical Circuit Diagnosis»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
2. Ignition OFF, all accessories OFF, install the J 37287 and CH-48027 . See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Ignition ON, command the fuel pump relay ON with a scan tool. Verify the fuel pressure is between 380-410 kPa (55-60 psi) and remains steady for 5 minutes.
4. Operate the vehicle within the conditions of the customers concern while monitoring fuel related parameters with a scan tool. If the scan tool parameters do not indicate a lean condition, refer to «Symptoms - Engine Controls»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .

1. Ignition ON, command the fuel pump relay ON with a scan tool and observe the fuel pressure while the fuel pump is operating. Verify the fuel pressure is between 380-410 kPa (55-60 psi). If the fuel pressure is more than the specified range, replace the fuel pump. If the fuel pressure is less than the specified range, remove the fuel tank and test/inspect for the following: Restricted fuel feed pipe Restricted or plugged fuel filter Restricted or plugged strainer Stuck or binding fuel level float Restricted siphon jet pump Restricted transfer lines between fuel tanks Faulty fuel pressure regulator Poor connections at the harness connectors and ground circuits of the fuel pump If you find a condition, repair as necessary. If all components test normal, replace the fuel pump.
2. Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 minute. 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 (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) . Install the J 37287 between the fuel feed pipe and the fuel rail. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . Open the valve on the J 37287 . See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . Bleed the air from the fuel pressure gage. Close the valve on the J 37287 . See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 minute. If the fuel pressure remains constant, replace the fuel pump. If the fuel pressure drops, locate and replace the leaking fuel injector.
3. 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 minutes. If the fuel pressure decreases more than the specified value, replace the fuel pump.
4. Remove the J 37287 and CH-48027 . See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
5. Operate the vehicle within the conditions of the customer concern while monitoring fuel related parameters with a scan tool. If the scan tool parameters indicate a lean condition, test/inspect for the following: Restricted fuel feed pipe Restricted fuel filter Restricted siphon jet pump Restricted transfer lines between fuel tanks Faulty fuel pressure regulator Poor connections at the harness connectors and ground circuits of the fuel pump If all components test normal and the scan tool parameters indicate a lean condition, replace the fuel pump.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) enables the appropriate fuel injector pulse for each cylinder. The ECM supplies a high voltage control circuit and a low control circuit to each of the fuel injectors. The control module controls each fuel injector 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. 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.

1. Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
2. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection.

Schematic Reference

Engine Controls Schematics

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Note. The engine coolant must be within the specified range or mis-diagnosis will occur. 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.

1. Engine coolant between 10-32°C (50-90°F).
2. Test for 1.30-1.73 ohms between the terminals of the fuel injector. The resistance of each fuel injector should be 1.30-1.73 ohms. If not within the specified range, replace the fuel injector.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Fuel Injector Replacement (LLT)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__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 more 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

1. Test the fuel composition using J 44175 Fuel Composition Tester and J44175-3 Instruction Manual. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. If water appears in the fuel sample clean the fuel system, refer to «Fuel System Cleaning»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-system-cleaning) .
3. 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.
4. If the fuel sample contains more than 15 percent ethanol, add fresh, regular gasoline to the vehicle's fuel tank.
5. Test the fuel composition.
6. If testing shows the ethanol percentage is still more than 15 percent, replace the fuel in the vehicle. Refer to «Fuel Tank Draining»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

Fuel Composition Test Examples

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__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 more 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.

1. 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.
2. 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.
3. Shake the cylinder vigorously for 10-15 seconds.
4. Carefully loosen the stopper in order to release the pressure.
5. Re-install the stopper and shake the cylinder vigorously again for 10-15 seconds.
6. 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 more 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.

1. Using an approved fuel container, draw approximately 0.5 liter (0.53 qt) of fuel.
2. 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 .

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ignition system on this engine uses individual ignition coils and ignition control (IC) 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 IC circuits. The ECM commands the IC circuit low when a spark event is requested. The sequencing and timing are controlled by the ECM.

1. 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.
2. 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

Description and Operation

Electronic Ignition (EI) System Description

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. J 26792 Spark Tester. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. J 43244 Relay Puller Pliers. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Ignition OFF, disconnect the harness connector of the ignition coil.
2. Ignition ON, load test for battery voltage between the ignition voltage circuit terminal 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.
3. Crank or start the engine. Test for 200-400 mV between the appropriate IC circuit terminal 1 and ground. If less than the specified value, test the IC circuit for a short to ground or an open/high resistance. If the circuit/connection tests normal, replace the ECM. If greater than the specified value, test the IC circuit for a short to voltage. If the circuit/connection tests normal, replace the ECM.
4. Connect a test lamp between the each of the ground circuits terminal 3, and terminal 4, and B+. The test lamp should illuminate on each circuit. If the test lamp does not illuminate, test the suspected circuit for an open/high resistance.
5. Test for 5 ohms or less between the ground circuit terminal A and ground. If greater than the specified value, repair the open, or high resistance in the ground circuit.
6. If all circuits/connections test normal, replace the ignition coil.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__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.

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

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

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

1. The air conditioning system
2. The catalytic converter efficiency
3. Comprehensive component monitoring-Emission related inputs and outputs
4. The evaporative emission (EVAP) system
5. The fuel delivery system
6. Heated catalyst monitoring
7. Misfire monitoring
8. The oxygen sensor system (O2S or HO2S)
9. The oxygen sensor heater system (HO2S heater)

For the specific DTCs required for each system, refer to Inspection/Maintenance (I/M) System DTC Table . Systems such as fuel delivery, 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.

1. Observe the Engine DTC information with a scan tool. If a DTC is set that would prevent the I/M System Status tests from completing, diagnose that DTC before continuing. Refer to «Inspection/Maintenance (I/M) System DTC Table»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis__inspectionmaintenance-im-system-dtc-table) .
2. 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 (I/M) Complete System Set Procedure»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .
3. Observe the I/M System Status indicators. If any I/M System Status indicators report NO, perform the «Inspection/Maintenance (I/M) Complete System Set Procedure»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis) .

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__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

1. The ignition voltage between 10 and 15 volts.
2. The barometric pressure (BARO) is more than 75 kPa.
3. The engine coolant temperature (ECT) at start-up is less than 42°C (108°F).
4. The intake air temperature (IAT) is between 2-32°C (36-90°F).
5. 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).
6. Fuel level is between 25 and 75 percent.

Review the Inspection/Maintenance (I/M) System Status indicators. All I/M System Status indicators should report YES.

Inspection/Maintenance (I/M) System Set Procedure

1. 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.
2. Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc., and open the hood.
3. Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
4. Start and idle the engine for 2 minutes.
5. 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 minutes.
6. Continue operation under these conditions for an additional 6 minutes.
7. Accelerate at part throttle to 90 km/h (55 mph) with this speed maintained for 2 minutes.
8. Release the accelerator pedal for at least 10 seconds. This will allow the vehicle to enter the decel fuel cut off.
9. 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 minutes.
10. 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 minutes.
11. 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) System DTC Table»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis__inspectionmaintenance-im-system-dtc-table) to identify the DTCs that did not run.

1. If any of the I/M System Status indicators display NO, refer to the «Inspection/Maintenance (I/M) System DTC Table»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-troubleshooting-diagnosis__inspectionmaintenance-im-system-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.

Inspection/Maintenance (I/M) System DTC Table

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Spark Plug Inspection
• Loss of Coolant (LH2, LY7, LLT)
• Oil Consumption Diagnosis
• DTC P2178, P2180, P2188, or P2190
• Symptoms - Engine Mechanical
• Knock Sensor (KS) System Description
• DTC P0326, P0327, P0328, P0331, P0332, or P0333
• Symptoms - Engine Exhaust
• Thermostat Diagnosis
• Engine Mount Inspection
• Temperature Versus Resistance - Engine Coolant Temperature Sensor
• Symptoms - Engine Electrical
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Battery Inspection/Test
• Engine Cranks Slowly
• Diagnostic Trouble Code (DTC) List - Vehicle
• Restricted Exhaust
• Diagnostic Repair Verification
• Relay Replacement (Attached to Wire Harness)
• Fuel Pressure Relief (With High Pressure Pump - LLT)
• Fuel System Cleaning
• Electronic Ignition (EI) System Description
• Road Test Warning
• DTC P0130 or P0150
• Symptoms Testing
• Fuel System Diagnosis
• Additional Symptoms Tests
• Inspection/Maintenance (I/M) System DTC Table