Engine Controls (Troubleshooting & Diagnosis) -- 3.5L (L66): Overview Saturn VUE I

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 2: If other instrument panel cluster (IPC) functions are not working correctly check for an open fuse or for a lack of power and ground to the IPC.

Malfunction Indicator Lamp (MIL) Inoperative

Description

The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks but Does Not Run diagnostic table directs the service technician to the appropriate system diagnosis. In order for the engine to start and run, the correct amount of good quality fuel must be properly delivered to each cylinder. The timing of the valve train operation in relation to piston position is also critical, as is mechanical compression of the air/fuel mixture.

The Engine Cranks but Does Not Run diagnostic table assumes the following

1. The battery is completely charged. Refer to «Battery Inspection/Test (Side Terminal Battery)»(ref-188769-S19691870562005090200000) or «Battery Inspection/Test (Top Post Terminal Battery)»(ref-188769-S40041861132005090200000) in Engine Electrical.
2. The engine cranking speed is acceptable. Refer to «Engine Cranks Slowly»(ref-188769-S26173659362005090200000) in Engine Electrical.
3. There is adequate fuel in the fuel tank.

The numbers below refer to the step numbers on the diagnostic table.

1. 1: The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. 2: The listed DTCs can cause a no start. If a DTC is set, diagnose the DTC before using this diagnostic procedure.
3. 3: A theft deterrent system condition, may cause a no start. If a theft deterrent DTC is set, diagnose the DTC before using this diagnostic procedure.
4. 4: If a crankshaft position (CKP) sensor is disconnected, a no start condition occurs without setting a DTC. If there is a condition with both CKP sensor circuits, a no start condition occurs without setting a DTC.
5. 7: This step verifies if there is any fuel pressure. If there is no fuel pressure the fuel system diagnosis must be performed.
6. 9: This step verifies if the engine will start and run. The repair that may have led to this step may only have been a secondary cause of the no start condition, such as fouled spark plugs. The diagnostics in this table may need to be performed a second time in order to discover the root cause of the no start condition.

Engine Cranks but Does Not Run

Scheme 120

The numbers below refer to the step numbers on the diagnostic table

1. 3: Command both the ON and OFF states. Repeat the commands as necessary. This can be determined by listening for an audible hiss from the fuel pump when the fuel pump relay is commanded ON or a vibration in the fuel feed line.
2. 4: This step determines if the condition is located on the coil side or the switch side of the relay.
3. 6: This step determines if the fuel pump relay is stuck closed.
4. 8: This step tests for a grounded voltage supply circuit. The fuel pump fuse supplies power to fuel pump. Disconnecting the fuel pump in-line harness connector isolates the fuel pump voltage supply circuit.
5. 10: This step verifies that the PCM is providing voltage to the fuel pump relay.
6. 11: This step verifies that the fuel pump fuse is providing voltage to the fuel pump relay.
7. 12: This step tests for an open circuit or a short to ground causing an open Maxifuse.
8. 13: This step bypasses the fuel pump relay in order to activate the fuel pump.
9. 14: This step tests for an open in the fuel pump feed circuit between the in-line connector and the fuel pump relay.
10. 17: This step tests for an open or high resistance in the fuel pump ground circuit.
11. 19: This step determines if the condition with the circuit is intermittent. If the fuse does not open, inspect the supply voltage circuit between the fuse and the fuel pump for an intermittent condition.

Fuel Pump Electrical Circuit Diagnosis

System Description

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.

The numbers below refer to the step numbers in the diagnostic table.

1. 1: The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. 3: This step determines whether the fuel pump can provide fuel within the correct regulated pressure range.
3. 4: This step tests that the fuel system can maintain fuel pressure with the pump Off. A fuel pressure drop of more than 55 kPa (8 psi) within the specified time indicates a leak in the fuel system.
4. 6: This step determines whether the loss in fuel pressure is on the fuel tank side of the system, or the fuel rail side.
5. 7: This step tests the operation of the fuel pressure regulator. If the fuel pressure exceeds the specified value, the fuel pressure regulator is faulty.
6. 8: This step tests for a restriction in the fuel system.

Fuel System Diagnosis

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step tests each fuel injector resistance within a specific temperature range. If any of the fuel injectors display a resistance outside of the specified value, replace the fuel injector.
2. 4: This step determines if all of the fuel injectors are within 3 ohms of each other. If the highest resistance value is within 3 ohms of the lowest resistance value, then all of the fuel injector coil windings are OK.
3. 5: This step determines which fuel injector is faulty. After subtracting the highest and lowest resistance values from the average value, replace the fuel injector that has the greatest resistance difference from the average.

Fuel Injector Coil Test

Scheme 121

Injector Balance Test Example

The numbers below refer to the step numbers in the diagnostic table.

1. 3: The engine coolant temperature must be less than the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
2. 4: The engine coolant temperature must be less than the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
3. 5: This step checks that the fuel pressure is within the specified operating range.
4. 6: This step checks for a steady fuel pressure reading. A steady fuel pressure reading indicates that the fuel system is operating properly.
5. 7: The fuel injectors are flowing properly if the pressure drop value for each fuel injector is within 10 kPa (1.5 psi) of the average pressure drop value. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading. Refer to the examples in the preceding table.

Fuel Injector Balance Test with Special Tool

The scan tool is first used to energize the fuel pump relay. The scan tool is then used to pulse each injector for a precise amount of time allowing a measured amount of fuel into the manifold. This causes a drop in system fuel pressure that can be recorded and used to compare each injector.

Injector Balance Test Example

The number below refers to the step number on the diagnostic table.

1. 3: The engine coolant temperature (ECT) must be below the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
2. 4: The engine coolant temperature must be less than the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.
3. 5: This step checks that the fuel pressure is within the specified operating range of this fuel system.
4. 6: This step checks for a steady fuel pressure reading. A steady fuel pressure reading indicates that the fuel system is operating properly.
5. 7: The fuel injectors are flowing properly if the pressure drop value for each fuel injector is within 10 kPa (1.5 psi) of the average pressure drop value. Calculate the pressure drop value for each fuel injector by subtracting the second pressure reading from the first pressure reading. Refer to the examples in the preceding table.

Fuel Injector Balance Test with Tech 2

The fuel tank leak test is used to locate any fuel or fuel vapor escaping the fuel tank area. Fuel vapors escaping above the fuel level will be detected when the evaporative emission (EVAP) diagnostics complete one test cycle. The malfunction indicator lamp (MIL) will illuminate after the EVAP diagnostics complete two test cycles.

The numbers below refer to the step numbers on the diagnostic table.

1. 1: Perform this procedure in order to determine that no EVAP diagnostic trouble code (DTC) is present.
2. 3: This test locates fuel leakage in the fuel pipes.
3. 4: This tests for fuel leaks below the fuel tank fuel level.
4. 5: This test locates fuel vapors escaping above the fuel level in the fuel tank.

Fuel Tank Leak Test

The numbers below refer to the step numbers on the diagnostic table.

1. 4: If the PCM does not detect a signal from either CKP sensor, the engine will not start. Damage wiring or a sensor that is disconnect causes this condition. If an engine speed is observed, there is no voltage available to the ignition coils. An open fuse in the supply circuit causes a no start and no communication with the scan tool.
2. 5: This step is tests for a condition with the control circuit of the ignition coil. If the voltage is not within the specified range, There is a condition with the control circuit of the ignition coil.
3. 16: After replacing the PCM, a new minimum throttle position and idle speed must be established.

Electronic Ignition (EI) System Diagnosis

Several states require that a vehicle pass on-board diagnostic (OBD) system tests and the 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.

The numbers below refer to the step numbers on the diagnostic table.

1. 1: Any DTCs set, even those that are not listed in the Inspection/Maintenance System DTC Table, may prevent the required DTCs from running. If there is any question as to whether a set DTC is disabling the required I/M diagnostic, review the Conditions for Running in the diagnostic procedures for the DTC required by the I/M diagnostic. A list of disabling DTCs, if applicable, is contained in the supporting text for that DTC.
2. 2: Anytime a control module is reprogrammed or the diagnostic trouble codes are cleared as part of a repair procedure, all the I/M System Status indicators will reset to NO.
3. 3: Use discretion when determining whether the entire system set procedure needs to be performed. For example, if the only tests that have not run are those that require the engine to be at operating temperature, then only those individual tests need to be run. There is no need to allow the engine to completely cool in order to run these tests.

Inspection/Maintenance (I/M) System Check

The purpose of the 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 diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform this test when more than one or all of the I/M System Status indicators are set to NO.

The numbers below refer to the step numbers in the diagnostic table.

1. 1: Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 2: This step is to run the heated oxygen sensor (HO2S) Heater tests and evaporative emission (EVAP) System tests.
3. 3: This step is to run the Catalyst test. The Catalyst test runs during the specified cruise period.
4. 4: This step is to set up the Oxygen Sensor (O2S) tests. These tests run during the idle period immediately following a cruise period that meets a minimum calibrated RPM and time period.
5. 5: This step is to run the Oxygen Sensor tests and the EVAP Tests. These tests run during the idle period immediately following a cruise period that meets a minimum calibrated RPM and time period.
6. 6: Perform the individual system test for any of the systems that do not update to YES.
7. 7: The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

Inspection/Maintenance (I/M) Complete System Set Procedure

The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the Catalyst System. The test may be used to set the I/M System Status indicators to YES. Ensure the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.

The numbers below refer to the step numbers in the diagnostic table.

1. 1: Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 2: The Catalyst test runs during the specified cruise period.
3. 3: This step is to identify a first failure of a type B DTC. A DTC only appears on the I/M System Status display when the DTC becomes a MIL illuminating DTC. This occurs on the second failure of a type B DTC. A first failure of a type B DTC will not allow the I/M System Status to update to YES. Refer to Diagnostic Aids.
4. 4: This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running the DTC.
5. 5: The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any Emission Related DTC sets after the tests are complete, the DTC will require diagnosis.

Inspection/Maintenance (I/M) Catalyst System Set Procedure

The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the exhaust gas recirculation (EGR) System. The test may be used to set the I/M System Status indicators to YES. Ensure the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.

The numbers below refer to the step numbers in the diagnostic table.

1. 1: Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 2: The Catalyst test runs during the specified cruise period.
3. 3: This step is to identify a first failure of a type B DTC. A DTC only appears on the I/M System Status display when the DTC becomes a MIL illuminating DTC. This occurs on the second failure of a type B DTC. A first failure of a type B DTC will not allow the I/M System Status to update to YES. Refer to Diagnostic Aids.
4. 4: This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running the DTC.
5. 5: The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any Emission Related DTC sets after the tests are complete, the DTC will require diagnosis.

Inspection/Maintenance (I/M) Exhaust Gas Recirculation (EGR) System Set Procedure

The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the evaporative emission (EVAP) system. The test may be used to set the I/M System Status indicators to YES. Service Bay Tests are included on the scan tool for some systems depending upon vehicle make and model. The test is designed to allow the EVAP Diagnostic Tests to run in service bay conditions. Ensure the vehicle meets the requirements listed in Conditions for Running before performing either EVAP System Test. Failure to meet the necessary requirements may produce inaccurate test results.

The numbers below refer to the step numbers in the diagnostic table.

1. 1: Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 2: The EVAP System test runs immediately following the idle period.
3. 3: This step is to identify a first failure of a type B DTC. A DTC only appears on the I/M System Status display when the DTC becomes a MIL illuminating DTC. This occurs on the second failure of a type B DTC. A first failure of a type B DTC will not allow the I/M System Status to update to YES. Refer to Diagnostic Aids.
4. 4: This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running the DTC.
5. 5: The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

Inspection/Maintenance (I/M) Evaporative Emission (EVAP) System Set Procedure

The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the heated oxygen sensor (HO2S) system. The test may be used to set the I/M System Status to YES. Ensure the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.

The numbers below refer to the step numbers on the diagnostic table.

1. 1: Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 2: Preprogramming the scan tool will reduce the amount of time the oxygen sensor heaters operate while verifying the enable criteria. The HO2S Heater Tests may not complete when initiated from a cold start and may require running under a load in order to complete the tests.
3. 3: This step is to identify a first failure of a type B DTC. A DTC only appears on the I/M System Status display when the DTC t becomes a MIL illuminating DTC. This occurs on the second failure of a type B DTC. A first failure of a type B DTC will not allow the I/M System Status to update to YES. Refer to Diagnostic Aids.
4. 4: This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running the DTC.
5. 5: The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

Inspection/Maintenance (I/M) Heated Oxygen Sensor/Oxygen Sensor (HO2S/O2S) System Set Procedure

The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the oxygen sensor (O2S, HO2S) system. The test may be used to set the I/M System Status to YES. Ensure the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.

The numbers below refer to the step numbers in the diagnostic table.

1. 1: Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 2: The oxygen sensor tests begin during the idle period immediately following the cruise period.
3. 3: This step is to identify a first failure of a type B DTC. A DTC only appears on the I/M System Status display when the DTC becomes a MIL illuminating DTC. This occurs on the second failure of a type B DTC. A first failure of a type B DTC will not allow the I/M System Status to update to YES. Refer to Diagnostic Aids.
4. 4: This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running the DTC.
5. 5: The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any Emission Related DTC sets after the tests are complete, the DTC will require diagnosis.

Inspection/Maintenance (I/M) Heated Oxygen Sensor (HO2S) Heater System Set Procedure