Engine Control System - 1.8L (Lnk) - Troubleshooting: Overview Pontiac Vibe I рестайлинг

Test Description

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

1. 2: This step checks whether there is communication between the PCM and a scan tool device. If the PCM is unable to provide serial data to the scan tool, there will be no MIL control.
2. 3: If other instrument panel cluster (IPC) functions are not working correctly check for an open GAUGE fuse or for a lack of power and ground to the IPC.
3. 4: This step checks for an open MIL control circuit or for an internal PCM failure.
4. 5: An open fuse determines if a voltage is constantly being applied to the control circuit.

Malfunction Indicator Lamp (MIL) Inoperative

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

1. 1: The Diagnostic System Check - Vehicle 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: Disconnecting the PCM will determine whether the malfunction is caused by a short to ground in the MIL control circuit or a faulty PCM.

Malfunction Indicator Lamp (MIL) Always On

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»(ref-200056-S11062095632005102000000) in Engine Electrical.
2. The engine cranking speed is acceptable. Refer to «Engine Cranks Slowly»(ref-200056-S21039774072005102000000) 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 - Vehicle 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: If a fuse is found to be the cause of the no start, locate and repair any shorts that may have caused the fuse to open before replacing the fuse.
3. 3: If there is a fault in either the CKP sensor or CMP sensor circuits, the ignition system can malfunction. Repair the cause of a DTC P0335, P0339, P0340, or P0341 first.
4. 4: If there is a fault in the electrical circuits between the PCM and the ignition coil assemblies, a DTC P0351-P0354 will set. Use the DTC P0351-P0354 diagnostic table in order to repair the ignition system failure.
5. 5: The fuel mixture may be too rich or too lean to start the engine if the engine coolant temperature (ECT) sensor signal is incorrect.
6. 6: The fuel mixture may be too rich or too lean to start the engine if the throttle position (TP) sensor signal is incorrect.
7. 7: The fuel mixture may be too rich or too lean to start the engine if the mass air flow (MAF) sensor signal is incorrect.
8. 11: This step verifies if there is any fuel pressure. If there is no fuel pressure the fuel pump electrical circuit must be inspected.
9. 17: 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

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

1. 1: The Diagnostic System Check - Vehicle 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. 6: This step will verify the ground path for the EFI relay circuit.

Ignition Relay Diagnosis

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

1. 1: The Diagnostic System Check - Vehicle 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: This step checks for the operation of the fuel pump. Fuel pump operation is difficult to hear without seat cushion removal.
3. 5: This step checks for the operation of the circuit opening relay. The circuit opening relay is located in the Instrument Panel Fuse Block and makes an audible click when turning ON and OFF.
4. 7: This step checks the control circuit of the fuel pump relay.
5. 9: The most likely location of an open circuit is between the splice and circuit opening relay terminal 2. An inoperative EFI relay would cause no MIL operation. The EFI relay is diagnosed in the No Malfunction Indicator Lamp diagnostic table.
6. 10: This step checks for a fault in the fuel pump or the circuit from the circuit opening relay to the fuel tank. The vehicle should start and run if the only fault was with the circuit opening relay.

Fuel Pump Electrical Circuit Diagnosis

System Description

The fuel supply system is a returnless design that has most of the fuel system components located inside of the fuel tank. When the ignition switch is turned to the START position and the engine is cranking, the circuit opening relay will be energized in order to allow the fuel pump to operate and pressurize the system. The fuel pump will continue to operate if the powertrain control module (PCM) receives a reference signal when the engine is started. The fuel pump operates as long as the circuit opening relay is energized by the PCM. When the circuit opening relay is de-energized, the fuel pump will stop operating. The fuel pump delivers fuel to the fuel rail at high pressure. The fuel pressure regulator, located in the fuel tank, is responsible for keeping the fuel pressure at 301-347 kPa (44-50 psi).

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

1. 1: The Diagnostic System Check - Vehicle 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. 6: This step checks the fuel pump for a worn bearing or a binding impeller. The pump should have a smooth and steady low humming sound. A loud humming or growling noise may indicate a faulty fuel pump. Check a known good vehicle in order to compare pump operation.
3. 12: The fuel system can not maintain constant fuel pressure with a leak in any of the following areas

1. The fuel pump check valve
2. The valve or valve seat within the fuel pressure regulator
3. The fuel injectors

1. 17: This step checks whether the fuel system is leaking between the fuel pressure gage and the fuel injectors or between the fuel pressure gage and the fuel sender assembly.
2. 20: This step checks for additional conditions that can cause low fuel pressure other than a faulty fuel pump. Check for any restrictions or blockage in the fuel feed lines and hoses, including those inside the fuel tank. Check the fuel pump electrical circuit for excessive resistance. Proper fuel pump operation requires correct voltage and adequate current flow.
3. 23: Check for rust and other foreign materials in the fuel tank. Clean or replace the fuel tank as necessary.

Fuel System Diagnosis

Scheme 186

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

1. 2: The engine coolant temperature (ECT) affects the ability of the fuel injector tester to detect a faulty fuel injector. Therefore, the test results are only valid when the engine coolant temperature is between 10-35°C (50-95°F).
2. 3: The first second of the voltage displayed by the DMM may be inaccurate due to the initial current surge; therefore, record the lowest voltage displayed by the DMM after the first second of the test. The voltage displayed by the DMM should be within the specified range. Refer to the Example. The voltage displayed by the DMM may increase throughout the test as the fuel injector windings warm and the resistance of the fuel injector windings changes. An erratic voltage reading, or large fluctuations in voltage that do not stabilize, indicates an intermittent connection within the fuel injector.

Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Between 10-35 Degrees C (50-95 Degrees F)

Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Between 10-35 Degrees C (50-95 Degrees F)

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

1. 2: The engine coolant temperature (ECT) affects the ability of the fuel injector tester to detect a faulty fuel injector.
2. 3: The first second of the voltage displayed by the DMM may be inaccurate due to the initial current surge; therefore, record the lowest voltage displayed by the DMM after the first second of the test. The voltage displayed by the DMM may increase throughout the test as the fuel injector windings warm and the resistance of the fuel injector windings changes. An erratic voltage reading, or large fluctuations in voltage that do not stabilize, indicates an intermittent connection within the fuel injector. From the voltages recorded, identify the highest voltage, excluding any voltages of more than 9.5 volts. Subtract each voltage that is not more than 9.5 volts from the highest voltage. Record each subtracted value. Refer to the Example. The subtracted value for any fuel injector must not exceed 0.8 volt. A fuel injector with a subtracted value that is more than 0.6 volt is considered faulty and must be replaced. A fuel injector with a recorded voltage of more than 9.5 volts is also considered faulty and must be replaced.

Fuel Injector Coil Test Example

Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Outside 10-35 Degrees C (50-95 Degrees F)

Scheme 187

Injector Balance Test Example (Typical)

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

1. 4: 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. 5: The fuel pressure should be within the specified range. If the fuel pressure is not within the specified range, refer to Fuel System Diagnosis.
3. 6: The fuel pressure should reach a steady value. If the fuel pressure does not reach a steady value, refer to Fuel System Diagnosis.
4. 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 numbers below refer to the step numbers on the diagnostic table.

1. 1: The Diagnostic System Check - Vehicle 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: This step checks for fuel injector control signals from the PCM.
3. 3: This step checks for a fault that affects all the fuel injectors.
4. 5: This step checks for a short in the fuel injector control circuit.
5. 8: This step checks for ignition positive voltage.

Fuel Injector Circuit Diagnosis

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

1. 1: A Diagnostic System Check-Vehicle 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. 4: This step tests whether the PCM can operate the IAC valve with the scan tool. The IAC valve can be commanded to increase and/or decrease engine speed by using the scan tool RPM Control function. Remember to clear any DTCs and run the engine until the engine reaches a normal operating temperature before attempting RPM Control with the scan tool.
3. 5: This step checks the operation of both electrical load idle-up circuits. If there is no increase in the IAC Motor Command percentage when the electrical accessory is turned ON, the idle-up circuit may be inoperative or always ON.
4. 6: This step checks the operation of the A/C idle-up circuit. If there is no increase in the IAC Motor Command percentage when the A/C compressor is engaged, the idle-up circuit may be inoperative or always ON.
5. 10: This step simulates the pulse width modulated (PWM) signal supplied to the IAC valve by the PCM by rapidly grounding and un-grounding terminal 1 of the IAC valve.
6. 12: The most likely cause of no ignition positive voltage is an open circuit condition between the IAC valve connector terminal 2 and the splice. A shorted or inoperative EFI relay circuit will cause a no-start condition.

Idle Air Control (IAC) System Diagnosis

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

1. 2: This step verifies that the vent port of the solenoid is open.
2. 3: This step verifies that the vent port of the solenoid is now closed.
3. 7: This step tests the control circuit of the solenoid.

Auxiliary Intake Air System Diagnosis

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

1. 1: The Diagnostic System Check-Vehicle 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: This step verifies whether the PCM responds to the operation of the rear defogger. The IAC Motor Command Cycle percentage and the idle speed will increase when the rear defogger is turned ON if the idle-up system is OK.
3. 3: This step verifies whether the PCM responds to the operation of the taillights. The IAC Motor Command Cycle percentage and the idle speed will increase when the taillights are turned ON if the idle-up system is OK.
4. 4: This step verifies the operation of the A/C idle circuit. If the engine idle speed and IAC Motor Command cycle increase when the A/C is turned ON, the A/C idle circuit is functioning normally.
5. 5: This step verifies the operation of the power steering pressure (PSP) switch circuit. If the engine idle speed and IAC Motor Command increase when the steering wheel is turned to 90 percent, the PSP switch idle circuit is functioning normally.
6. 6: This step tests the PSP switch signal circuit for voltage from the PCM.
7. 7: This step tests the operation of the PSP switch.
8. 10: The A/C compressor clutch should not be engaged with the A/C switch Off. The PCM will not increase engine idle speed when the A/C compressor is supposed to be Off.
9. 13: If the A/C compressor clutch engages, the compressor clutch, the relay, and the control circuit are all OK. The PCM will then need to be replaced because there was no increase in the IAC motor command percentage during A/C operation in Step 4.
10. 22: This step tests for a short to ground in the Diagnostic Request circuit. A short to ground in the Diagnostic Request circuit can cause the PCM to ignore the idle-up signals to the PCM. A short in the Diagnostic Request circuit will cause the IAC Motor Command and the idle speed to remain fixed.

Electrical/Accessory Load Idle-Up Signal Diagnosis

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

1. 2: If there is a fault in either the crankshaft position (CKP) sensor or camshaft position (CMP) sensor circuits, the ignition system can malfunction. Repair the cause of a DTC P0335 or DTC P0340 first.
2. 3: If there is a fault in the electrical circuits between the PCM and the ignition coil assemblies, a DTC P0351-P0354 will set. Use the DTC P0351-P0354 diagnostic table in order to repair the ignition system failure.
3. 7: This step checks for a condition that can cause a loss of spark, even though the test in step 4 indicated that there was good spark.
4. 10: This step checks whether the engine will start and run. A repair that has been performed leading to this step may only have been a contributing cause of a no start condition. Returning to the Engine Cranks but Does Not Run diagnostic table will locate additional causes of the no start condition.

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 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 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 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 inspection/maintenance (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 inspection/maintenance (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 on the diagnostic table.

1. 1: Perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES.
2. 3: This step is to initiate the EVAP System Test and to determine whether or not the EVAP System Test has run. If the system is operating correctly, the scan tool indicates that the system is complete and the I/M System Status updates to YES. If the EVAP Service Bay Test aborts because of lost enable conditions, the test can be repeated once the enable criteria is met.
3. 5: The EVAP system uses an electric vacuum pump in order to pressurize the system for diagnostic testing. After the engine has been OFF for 5 hours, the pump and EVAP solenoids will be energized, if the diagnostic enabling conditions have been met. An I/M System Status of YES, indicates that the diagnostic has run. If no DTCs are set, the EVAP system has passed.
4. 6: An I/M System Status of NO, indicates that the EVAP system diagnostic did not run to completion.

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

The purpose of this test is to satisfy the enable criteria necessary to execute inspection/maintenance (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/Oxygen Sensor (HO2S/O2S) System Set Procedure

The purpose of this test is to satisfy the enable criteria necessary to execute inspection/maintenance (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 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

See also:
• Scan Tool Data List
• Scan Tool Output Controls