MIL Operation
The MIL is located on the IPC.
MIL Function
- The MIL informs the driver that a malfunction has occurred and the vehicle should be taken in for service as soon as possible.
- The MIL illuminates during a bulb test and a system test.
- A DTC will be stored if a MIL is requested by the ECM.
MIL Illumination
- The MIL will illuminate with the ignition switch ON and the engine not running.
- The MIL will turn OFF when the engine is started.
- The MIL will remain ON if the self-diagnostic system has detected a malfunction.
- The MIL may turn OFF if the malfunction is not present.
- If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated as long as the ignition switch is ON.
- If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition switch is cycled OFF, then ON.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Turn ON the ignition, with the engine OFF. Is the instrument cluster completely inoperative? | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console | Go to Step 3 | |
| 3 | Turn ON the ignition, with the engine OFF. Command the MIL ON and OFF with a scan tool. Does the malfunction indicator lamp (MIL) turn ON and OFF when commanded with a scan tool? | Go to Intermittent Conditions | Go to Step 4 | |
| 4 | Inspect the fuse that supplies voltage to the cluster. Is the fuse open? | Go to Step 11 | Go to Step 5 | |
| 5 | Turn OFF the ignition. Remove the fuse that supplies voltage to the cluster. Disconnect the engine control module (ECM). Turn ON the ignition with the engine OFF. Measure the voltage from the MIL control circuit in the ECM harness connector to a good ground. Is the voltage less than the specified value? | 1 V | Go to Step 6 | Go to Step 12 |
| 6 | Turn OFF the ignition. Install the fuse that supplies voltage to the cluster. Turn ON the ignition with the engine OFF. Connect a 3-amp fused jumper wire between the MIL control circuit in the ECM harness connector and a good ground. Is the MIL illuminated? | Go to Step 10 | Go to Step 7 | |
| 7 | Turn OFF the ignition. Remove the instrument panel cluster (IPC). Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console. Turn ON the ignition. Probe the voltage supply circuit of the IPC harness connector with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 8 | Go to Step 13 | |
| 8 | Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition? | Go to Step 16 | Go to Step 9 | |
| 9 | Test for an intermittent and for a poor connection at the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 14 | |
| 10 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 15 | |
| 11 | Test all circuits and components that use this voltage supply for excessive current draw. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | ||
| 12 | Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 16 | ||
| 13 | Repair the open in the voltage supply circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 16 | ||
| 14 | Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement? | Go to Step 16 | ||
| 15 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 16 | ||
| 16 | Turn the ignition OFF for 30 seconds. Start the engine. Does the MIL operate correctly? | Go to Step 17 | Go to Step 2 | |
| 17 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
Malfunction Indicator Lamp (MIL) Inoperative
The MIL is located on the IPC.
MIL Function
- The MIL informs the driver that a malfunction has occurred and the vehicle should be taken in for service as soon as possible.
- The MIL illuminates during a bulb test and a system test.
- A DTC will be stored if a MIL is requested by the diagnostic.
MIL Illumination
- The MIL will illuminate with the ignition switch ON and the engine not running.
- The MIL will turn OFF when the engine is started.
- The MIL will remain ON if the self-diagnostic system has detected a malfunction.
- The MIL may turn OFF if the malfunction is not present.
- If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated as long as the ignition switch is ON.
- If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition switch is cycled OFF, then ON.
Test Description
The number below refers to the step number on the diagnostic table.
- 2: This step determines if the condition is with the MIL control circuit or the ECM.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Turn OFF the ignition. Disconnect the engine control module (ECM). Turn ON the ignition, with the engine OFF. Observe the malfunction indicator lamp (MIL). Is the MIL illuminated? | Go to Step 3 | Go to Step 5 |
| 3 | Remove the instrument panel cluster (IPC). Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console. Test the MIL control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 6 | Go to Step 4 |
| 4 | Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement? | Go to Step 6 | |
| 5 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 6 | |
| 6 | Turn the ignition OFF for 30 seconds. Start the engine. Does the MIL operate correctly? | Go to Step 7 | Go to Step 2 |
| 7 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
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 to not start. The diagnostic table directs the service technician to the appropriate system diagnosis. The diagnostic table assumes the following conditions are met
- The battery is completely charged. Refer to «Battery Inspection/Test»(ref-197559-S36532900252005101200000) in Engine Electrical.
- The engine cranking speed is acceptable. Refer to «Engine Cranks Slowly»(ref-197559-S07571509602005101200000) in Engine Electrical.
- There is adequate fuel in the fuel tank.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the DTC information with a scan tool. Does the scan tool display DTCs P0102, P0113, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0261, P0264, P0267, P0270, P0273, P0276, P0279, P0282, P0335, P0336, P0601, P0602, P0604, P0606, P0628, P0629, P0686, P0687, P0689, P0690, P1626, P1631, or P1636? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 | |
| 3 | Does the scan tool display any body control module (BCM) vehicle theft deterrent (VTD) DTCs? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 4 | |
| 4 | Turn ON the ignition, with the engine OFF. Probe both test points of the V8 ECM fuse located in the underhood electrical center using a test lamp connected to a good ground. Does the test lamp illuminate on at least one test point of the fuse? | Go to Step 5 | Go to Powertrain Relay Diagnosis | |
| 5 | Observe the engine speed parameter on the scan tool, while cranking the engine. Does the scan tool display 0 RPM? | Go to Step 9 | Go to Step 6 | |
| 6 | Turn OFF the ignition. Remove the ignition coil assembly from either bank. DO NOT disconnect any electrical connectors from the ignition coil assembly. Refer to Ignition Coil(s) Replacement - Bank 1 or Ignition Coil(s) Replacement - Bank 2 . Install the J 36012-A Ignition Diagnostic Harness. See Special Tools . Install the J 26792 Spark Tester on one of the spark plug jumper wires. Attach the clamp end of the spark tester to a good ground. Crank the engine with the remaining spark plug jumper wires connected. Repeat steps 5-7 for each remaining cylinder on this bank. Repeat the procedure for the opposite bank. Reassemble the vehicle after performing the procedure. Did the spark tester spark on all cylinders? | Go to Step 7 | Go to Electronic Ignition (EI) System Diagnosis | |
| 7 | IMPORTANT: 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. Install a J 34730-1A Fuel Pressure Gage. Refer to Fuel Pressure Gage Installation and Removal . Turn ON the ignition, with the engine OFF. IMPORTANT: The fuel pump may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. Command the fuel pump ON with a scan tool. Observe the fuel pressure while the fuel pump is operating. Is the fuel pressure within the specified range? | 380-410 kPa (55-60 psi) | Go to Step 8 | Go to Fuel System Diagnosis |
| 8 | Inspect for the following conditions: A collapsed air intake duct A restricted air filter element - Refer to Air Cleaner Element Replacement . Fouled spark plugs - Refer to Spark Plug Replacement and Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition. Contaminated fuel - Refer to Alcohol/Contaminants-in-Fuel Diagnosis (W/Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (W/O Special Tool) . An engine mechanical condition, for example, broken timing chain, low compression - Refer to Setting Camshaft Timing and Engine Compression Test in Engine Mechanical. A restricted exhaust system - Refer to Restricted Exhaust in Engine Exhaust. An ECT sensor that has shifted in value - Refer to Temperature vs Resistance . Proper operation of the MAP sensor - Refer to DTC P0106 . Did you complete the action? | Go to Step 15 | ||
| 9 | Turn ON the ignition with the engine OFF. Test for a short between the mass air flow (MAF) sensor 12-volt reference circuit and the following circuits: The intake air temperature (IAT) 5-volt reference circuit The IAT low reference circuit Refer to Circuit Testing in Wiring Systems. Did you find and correct the condition. | Go to Step 15 | Go to Step 10 | |
| 10 | Disconnect a camshaft position sensor. Install a DMM between the camshaft position sensor 12-volt reference circuit and a good ground. Monitor the DMM while disconnecting the MAF/IAT sensor. If the voltage changes while disconnecting the MAF/IAT sensor, replace the MAF/IAT sensor. Did you replace the sensor? | Go to Step 15 | Go to Step 11 | |
| 11 | Disconnect the MAF sensor. Install a DMM between the MAF sensor 12-volt reference circuit and a good ground. Monitor the DMM while disconnecting all other sensors connected to the 12-volt reference circuit, one at a time. If the voltage changes when one of the sensors are disconnected, replace the sensor. Did you replace a sensor? | Go to Step 15 | Go to Step 12 | |
| 12 | Test the 12-volt reference circuits of the following components for a short to ground. Refer to Circuit Testing in Wiring Systems. MAF/IAT airflow sensor Crankshaft position (CKP) Sensor CMP sensor bank 1 (right) exhaust CMP sensor bank 2 (left) exhaust CMP sensor bank 1 (right) Intake CMP sensor bank 2 (left) Intake Did you find and correct the condition? | Go to Step 15 | Go to Step 13 | |
| 13 | Test for shorted terminals and poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 14 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 15 | ||
| 15 | With a scan tool, clear the DTCs. Attempt to start the engine. Does the engine start and continue to operate? | Go to Step 16 | Go to Step 2 | |
| 16 | Idle the engine. Allow the engine to reach operating temperature. Observe the DTC information with a scan tool. Are any DTCs displayed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK | |
| IMPORTANT |
|---|
| 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. |
| IMPORTANT |
|---|
| The fuel pump may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. |
Engine Cranks but Does Not Run
The numbers below refer to the step numbers on the diagnostic table
- 2: Command both the ON and OFF states. Repeat the commands as necessary.
- 3: This step determines if the condition is located on the coil side or the switch side of the circuit.
- 7: 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.
- 9: This step verifies that the fuel pump fuse is providing voltage to the fuel pump relay.
- 10: This step jumps the fuel pump relay in order to activate the fuel pump.
- 15: 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.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Turn ON the ignition, with the engine OFF. Command the fuel pump relay ON and OFF with a scan tool. Does the fuel pump turn ON and OFF? | Go to Diagnostic Aids | Go to Step 3 |
| 3 | Command the fuel pump relay ON and OFF with a scan tool. Do you hear a click when you command the fuel pump relay ON and OFF? | Go to Step 4 | Go to Step 16 |
| 4 | Turn ON the ignition, with the engine OFF. Does the fuel pump operate continuously? | Go to Step 5 | Go to Step 6 |
| 5 | Turn OFF the ignition. Remove the rear seat. Refer to 7288 3 in Seats. Disconnect the fuel pump relay. Turn ON the ignition, with the engine OFF. Does the fuel pump operate continuously? | Go to Step 17 | Go to Step 20 |
| 6 | Is the fuel pump fuse open? | Go to Step 7 | Go to Step 9 |
| 7 | Disconnect the fuel pump harness in-line connector located near the fuel tank. Refer to Power and Grounding Connector End Views in Wiring Systems. Test the supply voltage circuit of the fuel pump for a grounded circuit. Refer to Wiring Repairs and Connector Repairs in Wiring Systems. Replace the fuel pump fuse, if necessary. Did you find and correct the condition? | Go to Step 21 | Go to Step 8 |
| 8 | Lower the fuel tank, if necessary. Refer to Fuel Tank Replacement . Test or inspect the fuel tank electrical harness for the following conditions: Damage to the harness A grounded circuit - Refer to Circuit Testing and Wiring Repairs in Wiring Systems Replace the fuel pump fuse, if necessary. Did you find and correct the condition? | Go to Step 21 | Go to Step 15 |
| 9 | Turn OFF the ignition. Disconnect the fuel pump relay. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the fuel pump relay with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 10 | Go to Step 18 |
| 10 | Connect a 15-amp fused jumper wire between the battery positive voltage circuit and the fuel pump supply circuit of the fuel pump relay. Does the fuel pump operate? | Go to Step 16 | Go to Step 11 |
| 11 | Disconnect the fuel pump harness in-line connector located near the fuel tank. Refer to Power and Grounding Connector End Views in Wiring Systems. Test the supply voltage circuit of the fuel pump for an open or for high resistance between the fuel pump relay and the in-line connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 21 | Go to Step 12 |
| 12 | IMPORTANT: Inspect the ground circuit for being tight, for corrosion on the terminals, or for damage to the wiring harness. Test the ground circuit of the fuel pump for an open or for high resistance between the body pass through connector and the ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition? | Go to Step 21 | Go to Step 13 |
| 13 | Inspect for poor connections at the fuel pump in-line connector to the body pass through connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 21 | Go to Step 14 |
| 14 | Lower the fuel tank. Refer to Fuel Tank Replacement . Test or inspect the fuel tank electrical harness for the following conditions: Damage to the harness An open circuit - Refer to Circuit Testing and Wiring Repairs in Wiring Systems Did you find and correct the condition? | Go to Step 21 | Go to Step 19 |
| 15 | Connect all disconnected components. Install a new fuel pump fuse. Command the fuel pump ON with a scan tool. Is the fuel pump fuse open? | Go to Step 19 | Go to Diagnostic Aids |
| 16 | Inspect for poor connections at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 21 | Go to Step 20 |
| 17 | Repair the supply voltage circuit of the fuel pump for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 21 | |
| 18 | Repair the battery positive voltage circuit of the fuel pump relay for an open. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 21 | |
| 19 | IMPORTANT: Inspect for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump. Replace the fuel tank module. Refer to Fuel Tank Module Replacement - Primary . Replace the fuel pump fuse, if necessary. Did you complete the replacement? | Go to Step 21 | |
| 20 | Replace the fuel pump relay. Did you complete the replacement? | Go to Step 21 | |
| 21 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
| IMPORTANT |
|---|
| Inspect the ground circuit for being tight, for corrosion on the terminals, or for damage to the wiring harness. |
| IMPORTANT |
|---|
| Inspect for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump. |
Fuel Pump Electrical Circuit Diagnostic
System Description
When you turn the ignition switch to the ON position, the control module enables the fuel pump relay, which in turn powers the fuel pump. The fuel pump remains ON as long as the engine is cranking or running and the control module receives ignition reference pulses. If there are no ignition reference pulses, the control module shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position, or if the engine stops.
The fuel tank stores the fuel supply. The fuel pump is an electric pump that is attached to the primary fuel tank module assembly. The fuel pump also supplies fuel to the siphon jet pump, also attached to the primary fuel tank module. The siphon jet pump draws fuel from the secondary side of the fuel tank to the primary side of the fuel tank. The fuel pump is designed to provide fuel at a pressure above the pressure that is needed by the fuel injectors. A fuel pressure regulator, which is also located in the fuel tank, is attached to the primary fuel tank module. The fuel pressure regulator keeps the fuel available to the fuel injectors at a regulated pressure. The port on the fuel pressure regulator is an atmospheric vent. The fuel pressure regulator does not compensate for changes in intake manifold vacuum. Unused fuel is returned from the fuel filter to the fuel tank by a separate fuel return pipe.
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step verifies that the fuel pump is operating.
- 4: This step verifies that the vehicle is not out of fuel. If the right fuel sender is below 0.8 volts, and the left fuel sender is above 0.8 volts, a fuel transfer condition exists.
- 7: This step tests for an internal fuel leak. If the fuel pressure drops during this test, then an internal loss of pressure is indicated.
- 10: This step isolates the condition. Replace the primary fuel tank module assembly, if the fuel pressure remains constant, after closing the valve on the fuel pipe shut-off adapter. Locate and replace the leaking fuel injector if the pressure continues to decrease after closing the valve on the adapter.
- 13: This step isolates the condition. Replace the primary fuel tank module assembly for a stuck open or leaking fuel pressure regulator, if the fuel pressure increases above the specified value.
- 16: This step verifies that a circuit condition is not the cause of a fuel pressure concern. Inspect all fuel pump electrical circuits thoroughly.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Fuel Hose/Pipes Routing Diagram | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | IMPORTANT: Inspect the fuel system for the following conditions before proceeding with this diagnostic procedure: Damage to the fuel system External fuel leaks Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Does the fuel pump operate? | Go to Step 3 | Go to Fuel Pump Electrical Circuit Diagnosis | |
| 3 | Observe the fuel level sensor left voltage with a scan tool. Is the fuel level sensor left voltage less than the specified value? | 0.8 V | Go to Step 4 | Go to Step 6 |
| 4 | Observe the fuel level sensor right voltage with a scan tool. Is the fuel level sensor right voltage less than the specified value? | 0.8 V | Go to Step 5 | Go to Step 14 |
| 5 | Add the specified amount of fuel. Operate the vehicle within the conditions of the customer's concern. Monitor the fuel trim related parameters with a scan tool. Refer to Scan Tool Data List . Do any of the scan tool parameters indicate a lean condition? | 19 L (5 gal) | Go to Step 15 | Go to Symptoms - Engine Controls |
| 6 | Turn OFF the ignition. Install the fuel pressure gage. Refer to Fuel Pressure Gage Installation and Removal . Turn ON the ignition, with the engine OFF. IMPORTANT: The fuel pump may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. DO NOT start the engine. Command the fuel pump ON with a scan tool. Observe the fuel pressure gage while the fuel pump is operating. Is the fuel pressure within the specified range? | 380-410 kPa (55-60 psi) | Go to Step 7 | Go to Step 11 |
| 7 | IMPORTANT: The fuel pressure will drop when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Allow the fuel pressure to stabilize. Monitor the fuel pressure gage for 1 minute. Does the fuel pressure decrease by more than the specified value? | 34 kPa (5 psi) | Go to Step 10 | Go to Step 8 |
| 8 | Relieve the fuel pressure to the first specified value. Monitor the fuel pressure gage for 5 minutes. Does the fuel pressure decrease by more than the second specified value? | 69 kPa (10 psi) 14 kPa (2 psi) | Go to Step 19 | Go to Step 9 |
| 9 | Operate the vehicle within the conditions of the customer's concern. Monitor the fuel related parameters with a scan tool. Do any of the scan tool parameters indicate a lean condition? | Go to Step 15 | Go to Symptoms - Engine Controls | |
| 10 | Turn OFF the ignition. Relieve the fuel pressure. Refer to Fuel Pressure Relief Procedure . Disconnect the fuel feed pipe from the fuel rail. Refer to Quick Connect Fitting(s) Service (Metal Collar) . Install the appropriate J 37287 Fuel Line Shut-Off Adapters between the fuel feed pipe and the fuel rail inlet. Open the valve on the fuel feed pipe shut-off adapter. Command the fuel pump ON with a scan tool. Bleed the air from the fuel system. Close the fuel pipe shut-off valve. Monitor the fuel pressure gage for 1 minute. Does the fuel pressure remain constant? | Go to Step 19 | Go to Step 18 | |
| 11 | Is the fuel pressure more than the specified value? | 410 kPa (60 psi) | Go to Step 12 | Go to Step 13 |
| 12 | Inspect the fuel return hose/pipe for a restriction. Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 13 | Turn OFF the ignition. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure . Disconnect the fuel return hose from the fuel return outlet of the fuel filter. Refer to Quick Connect Fitting(s) Service (Plastic Collar) . Install the appropriate J 37287 between the return outlet of the fuel filter and the fuel return hose. Open the valve in the fuel pipe shut-off adapter. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Bleed the air from the fuel system. Monitor the fuel pressure gauge. Slowly close the valve in the fuel pipe shut-off adapter. Command the fuel pump ON with a scan tool. Does the fuel pressure increase to more than the specified value? | 380-410 kPa (55-60 psi) | Go to Step 19 | Go to Step 15 |
| 14 | Remove both fuel tank modules. Refer to Fuel Tank Module Replacement - Primary and Fuel Tank Module Replacement - Secondary . Inspect the feed fuel pipe of the siphon jet pump for a restriction. Inspect the fuel strainer for contaminants. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (W/Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (W/O Special Tool) . Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 15 | Inspect the following components for a restriction: The fuel filter The fuel feed pipe Did you find and correct the condition? | Go to Step 20 | Go to Step 16 | |
| 16 | Inspect the harness connectors and ground circuits of the fuel pump for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 17 | |
| 17 | Remove the primary fuel tank module. Refer to Fuel Tank Module Replacement - Primary . Inspect the following items: The fuel pump flex hose for damage The in-tank fuel pump harness connectors for poor connections The fuel strainer for a restriction For contaminates in the fuel tank Refer to Alcohol/Contaminants-in-Fuel Diagnosis (W/Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (W/O Special Tool) . Did you find and correct the condition? | Go to Step 20 | Go to Step 19 | |
| 18 | Turn OFF the ignition. Raise the fuel rail, with the fuel lines connected. Refer to Fuel Injectors and Fuel Rail Replacement . Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Locate and replace the leaking fuel injector. Refer to Fuel Injectors and Fuel Rail Replacement . Did you complete the replacement? | Go to Step 20 | ||
| 19 | Replace the primary fuel tank module. Refer to Fuel Tank Module Replacement - Primary . Did you complete the replacement? | Go to Step 20 | ||
| 20 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 | |
| IMPORTANT |
|---|
| Inspect the fuel system for the following conditions before proceeding with this diagnostic procedure: Damage to the fuel system External fuel leaks |
| IMPORTANT |
|---|
| The fuel pump may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. DO NOT start the engine. |
| IMPORTANT |
|---|
| The fuel pressure will drop when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. |
Fuel System Diagnosis
The scan tool is first used to energize the fuel pump. The fuel injector tester 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.
| Cylinder | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| 1st Reading | 380 kPa (55 psi) | 380 kPa (55 psi) | 380 kPa (55 psi) | 380 kPa (55 psi) |
| 2nd Reading | 215 kPa (31 psi) | 201 kPa (29 psi) | 208 kPa (30 psi) | 229 kPa (33 psi) |
| Amount of Drop | 165 kPa (24 psi) | 179 kPa (26 psi) | 172 kPa (25 psi) | 151 kPa (22 psi) |
| Average Range: 156-176 kPa (22.5-25.5 psi) | Injector OK | Replace fuel injector - too much fuel pressure drop | Injector OK | Replace fuel injector - too little fuel pressure drop |
Fuel Injector Balance Test Example (Typical)
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check- Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Did you perform the Fuel Injector Coil Test? | Go to Step 3 | Go to Fuel Injector Coil Test | |
| 3 | IMPORTANT: DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). IMPORTANT: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. Install the fuel pressure gage. Refer to Fuel Pressure Gage Installation and Removal . Turn ON the ignition, with the engine OFF. IMPORTANT: The fuel pump may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure. Command the fuel pump ON with a scan tool. Observe the fuel pressure gage, with the fuel pump operating. Is the fuel pressure within the specified range? | 380-427 kPa (55-62 psi) | Go to Step 4 | Go to Fuel System Diagnosis |
| 4 | IMPORTANT: The fuel pressure will decrease when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Monitor the fuel pressure gage for 5 minutes.Does the fuel pressure decrease to less than the specified value? | 350 kPa (51 psi) | Go to Fuel System Diagnosis | Go to Step 5 |
| 5 | NOTE: Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding. Connect the J 39021 Fuel Injector Tester to a fuel injector using the J 44602 Injector Test Adapter. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position. Command the fuel pump ON and OFF with a scan tool. Record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the first pressure reading. IMPORTANT: Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. Do not record the higher fuel pressure value. Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester. Record the fuel pressure indicated by the fuel pressure gage after the fuel injector has stopped pulsing. This is the second fuel pressure reading. Repeat steps 1 through 6 for each fuel injector. Subtract the second pressure reading from the first pressure reading for one fuel injector. The result is the pressure drop value. Obtain a pressure drop value for each fuel injector. Add all of the individual pressure drop values. This is the total pressure drop. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop. Is the difference between any individual pressure drop and the average pressure drop more than the specified value? | 10 kPa (1.5 psi) | Go to Step 6 | Go to Symptoms - Engine Controls |
| 6 | Replace the affected fuel injector. Refer to Fuel Injectors and Fuel Rail Replacement . Did you complete the replacement? | Go to Step 7 | ||
| 7 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Symptoms - Engine Controls |
| IMPORTANT |
|---|
| DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). |
| IMPORTANT |
|---|
| Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. |
| IMPORTANT |
|---|
| The fuel pump may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure. |
| IMPORTANT |
|---|
| The fuel pressure will decrease when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. |
| NOTE |
|---|
| Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding. |
| IMPORTANT |
|---|
| Record the fuel pressure value immediately after the fuel injector stops pulsing. The fuel pressure may rise after the fuel injector stops pulsing. Do not record the higher fuel pressure value. |
Fuel Injector Balance Test with Special Tool
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 emissions (EVAP) leak diagnostic completes one test cycle. The malfunction indicator lamp (MIL) will illuminate after the EVAP leak diagnostic completes two test cycles only when a condition is detected.
- 3: This step tests for location of fuel leakage in the fuel lines.
- 4: This step tests for fuel leaks below the fuel level in the fuel tank.
- 5: This step tests for a location of fuel vapors escaping above the fuel level in the fuel tank.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | CAUTION: Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Inspect the fuel tanks and the fuel pipes for damage or external leaks. Did you find fuel leaking from the fuel tank? | Go to Step 7 | Go to Step 3 |
| 3 | Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Inspect for fuel leaking from the fuel pipe. Did you locate a fuel leak from the fuel pipes? | Go to Step 8 | Go to Step 4 |
| 4 | Install the J 41415-40 or GE-41415-50 Fuel Tank Cap Adapter. See Special Tools . Connect the J 41413-200 Evaporative Emissions System Tester (EEST) to the J 41415-40 or GE-41415-50 . See Special Tools . Command the evaporative emissions (EVAP) vent valve ON with a scan tool. Pressurize the fuel tank with the J 41413-200 . Inspect for a fuel leak from the fuel tank. Did you locate a fuel leak from the fuel tank? | Go to Step 7 | Go to Step 5 |
| 5 | Turn the Nitrogen/Smoke valve on the J 41413-200 control panel to SMOKE. Use the remote switch to introduce smoke into the sealed system. Inspect the entire system with the with the J 41413-SPT High Intensity White Light for exiting smoke. Did you locate a leak source? | Go to Step 6 | Go to Diagnostic Aids |
| 6 | Repair the system as necessary. Did you complete the repair? | System OK | |
| 7 | Replace the fuel tank. Refer to Fuel Tank Replacement . Did you complete the repair? | System OK | |
| 8 | Replace the leaking fuel pipe. Refer to Fuel Hoses/Pipes Replacement - Filter to Tank and Fuel Hose/Pipes Replacement - Chassis . Did you complete the replacement? | System OK |
| CAUTION |
|---|
| Refer to Gasoline/Gasoline Vapors Caution in Cautions and Notices. |
Fuel Tank Leak Test
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.
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.
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 comply with the local area requirements.
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 on the diagnostic table.
- 2: This step runs the HO2S Heater Tests and initiate the EVAP System Test. Preprogramming the scan tool will reduce the amount of time the oxygen sensor heaters operate while verifying the enable criteria.
- 3: This step runs the EVAP, AIR, and the oxygen sensor (O2S) tests. The EVAP test begins once the engine coolant reaches a calibrated temperature. The AIR test, if equipped, begins shortly after Closed Loop and the indicated speed is achieved. The oxygen sensor tests begin once the engine is at operating temperature, in Closed Loop fuel control, and a calibrated amount of time has elapsed.
- 5: The I/M System Status only reports on whether or not a diagnostic has run, not the outcome of the test. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Inspection/Maintenance (I/M) System Check? | Go to Step 2 | Go to Inspection/Maintenance (I/M) System Check | |
| 2 | IMPORTANT: Whenever the ignition is turned ON, ignition positive voltage is supplied to the heated oxygen sensor (HO2S) heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Once the engine is started, DO NOT turn the engine OFF for the remaining portion of the set procedure. Preprogram the scan tool with the vehicle information before the ignition is turned ON. Ensure that the vehicle is within the Conditions for Running specified in the supporting text. Turn OFF all of the accessories, e.g., A/C, blower fan, etc. Set the vehicle parking brake. Verify the transmission is in Park for automatic transmissions and Neutral for manual transmissions. Start the engine and allow the engine to idle for the specified time Is the action complete? | 2 minutes | Go to Step 3 | |
| 3 | CAUTION: Refer to Road Test Caution in Cautions and Notices. In order for the next group of tests to run, the vehicle must operate in the following conditions: Acceleration at part throttle to 90 km/h (55 mph). Continued operation under these conditions for an additional 15 minutes. Is the action complete? | Go to Step 3 | ||
| 4 | Observe the I/M System Status display with a scan tool. Did all of the I/M System Status indicators update to YES? | Go to Step 5 | Go to the I/M System Set Procedure for the indicated systems. | |
| 5 | Observe the Emission Related DTC portion of the I/M System Status display with a scan tool. Does the scan tool indicate any Emission Related DTCs set? | Go to Inspection/Maintenance (I/M) System DTC Table | System OK |
| IMPORTANT |
|---|
| Whenever the ignition is turned ON, ignition positive voltage is supplied to the heated oxygen sensor (HO2S) heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Once the engine is started, DO NOT turn the engine OFF for the remaining portion of the set procedure. |
| CAUTION |
|---|
| Refer to Road Test Caution in Cautions and Notices. |
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.
The purpose of this test is to satisfy the enable criteria necessary to execute the inspection/maintenance (I/M) readiness diagnostics for the Evaporative Emission (EVAP) System. The test may be used in order to set the I/M System Status indicators to YES. The I/M System Status Display on the scan tool provides an indication of when the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the other tests for that system have not run. If a small leak is detected, a minimum of 3 drive cycles may be required before the I/M System Status will update to YES. Performing a visual inspection prior to running the EVAP test may prevent having to repeat the test. A failed or aborted test will require the vehicle to cool down in order to meet the enable criteria to run another test.
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)/oxygen sensor (O2S) System. The test may be used to set the I/M System Status to YES.
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.