MIL Operation
The MIL is located on the instrument panel cluster (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.
Test Description
The number below refers to the step number on the diagnostic table.
- 4: This step tests for a short to voltage on the MIL control circuit. With the fuse removed there should be no voltage on the MIL control circuit.
| 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 - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Verify whether the instrument cluster is operational. If the instrument panel (I/P) is completely inoperative, refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gages and Console. Command the malfunction indicator lamp (MIL) ON and OFF with a scan tool. Does the MIL turn ON and OFF when commanded with a scan tool? | Go to Intermittent Conditions | Go to Step 3 | |
| 3 | Inspect the fuse that supplies battery voltage to the cluster. Is the fuse open? | Go to Step 10 | Go to Step 4 | |
| 4 | Turn OFF the ignition. Remove the fuse that supplies battery 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 5 | Go to Step 11 |
| 5 | Turn OFF the ignition. Install the fuse that supplies battery 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 9 | Go to Step 6 | |
| 6 | Turn OFF the ignition. Remove the instrument panel cluster (IPC). Refer to Instrument Panel (I/P) Assembly Replacement in Instrument Panel, Gages, and Console. Turn ON the ignition, with the engine OFF. Probe the battery voltage 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 7 | Go to Step 12 | |
| 7 | 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 15 | Go to Step 8 | |
| 8 | 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 15 | Go to Step 13 | |
| 9 | Test for an intermittent and for a poor connection at the ECM. Refer to 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 | |
| 10 | Test all circuits and components that are supplied by this fuse 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 15 | Go to Intermittent Conditions | |
| 11 | 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 15 | ||
| 12 | Repair the open or the short to ground in the battery voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 15 | ||
| 13 | Replace the IPC. Refer to Instrument Panel (I/P) Assembly Replacement in Instrument Panel, Gages and Console. Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the ECM. Refer to Engine Control Module (ECM) Replacement . Did you complete the replacement? | Go to Step 15 | ||
| 15 | Turn OFF the ignition for 30 seconds. Start the engine. Does the MIL operate correctly? | Go to Step 16 | Go to Step 2 | |
| 16 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List | System OK | |
Malfunction Indicator Lamp (MIL) Inoperative
The MIL is located on the instrument panel (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 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 so 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.
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 PCM.
| 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-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls |
| 2 | Turn OFF the ignition. Disconnect the ECM. Turn ON the ignition, with the engine OFF. Observe the MIL. Is the MIL illuminated? | Go to Step 3 | Go to Step 5 |
| 3 | Remove the instrument panel cluster (IPC). Refer to Instrument Panel (I/P) Assembly 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 (I/P) Assembly Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement? | Go to Step 6 | |
| 5 | Replace the ECM. Refer to Engine Control Module (ECM) Replacement . Did you complete the replacement? | Go to Step 6 | |
| 6 | Turn the ignition OFF for 30 seconds. Start the engine. Does the vehicle operate correctly without any MIL illumination, and without any stored DTCs? | System OK | Go to Diagnostic System Check - Engine Controls |
Malfunction Indicator Lamp (MIL) Always On
The numbers below refer to the step numbers on the diagnostic table.
- 5: This step tests for an ignition 1 voltage supply to the engine control module (ECM).
- 6: If there is fuel in the engine oil, fuel may be leaking from the fuel injector or fuel injection pump into the crankcase.
- 7: If the fuel system will not even briefly prime to 10 psi and will not start, the check valve in the fuel filter/heater element housing is stuck open.
- 8: This step determines if the fuel system is bleeding down causing a no start. The fuel pressure will slowly drop to 0 psi, but should still be above 8 psi 10 seconds after pressurizing the fuel system.
- 9: In some cases, no compression, possibly with excessive fuel, in a single cylinder can cause a no start.
- 10: This step determines if the problem is a stuck open or broken fuel injector. If fuel vapors come out of any of the glow plug holes, excessive fuel is being sent into a cylinder, and not being distributed to all of the fuel injectors.
- 11: The engine will not run without an actual fuel rail pressure more than 10 MPa (1,450 psi).
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the DTC Information with a scan tool. Does the scan tool display DTC P0090, P0193, P0335, P0336, P0340, P0370, P0374, P0601, P0602, P0603, P0604, P0611, P0612, P0642, P0643, P0670, P0698, P0699, P1621, P1626, P1631, P1683, P1687, or U0105? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3 | |
| 3 | Is the customer concern with a fuel smell or fuel leak? | Go to Fuel Leaks | Go to Step 4 | |
| 4 | Observe the Actual Fuel Rail Pressure parameter with a scan tool. Is the pressure within the specified range? | 1-1.8 MPa | Go to Step 5 | Go to Step 15 |
| 5 | Observe the Ignition 1 signal parameter with a scan tool. Is the Ignition 1 signal parameter at the specified value? | B+ | Go to Step 6 | Go to Step 18 |
| 6 | Inspect for the following conditions: Excessive fuel in the engine oil-Refer to Fuel in Engine Oil in Engine Mechanical. Fuel specific gravity-Refer to Contaminants-in-Fuel Diagnosis . Did you find and correct the condition? | Go to Step 26 | Go to Step 7 | |
| 7 | Install the J 44638 Vacuum Gage to the fuel system service port on the right front side of the engine. Attempt to hand prime the fuel manager 30 times or until the specified pressure is reached. Can you prime the system to the specified value? | 8 psi | Go to Step 8 | Go to Step 23 |
| 8 | Does the pressure measure more than the specified value for more than 2 minutes? | 2 psi | Go to Step 9 | Go to Step 12 |
| 9 | Perform the Engine Compression Test. Refer to Engine Compression Test in Engine Mechanical. Repair the engine as necessary. Did you find and correct the condition? | Go to Step 27 | Go to Step 10 | |
| 10 | Did any of the cylinders emit any fuel vapor during the Engine Compression Test? | Go to Step 22 | Go to Step 11 | |
| 11 | Crank the engine for 15 seconds. Observe the Actual Fuel Rail Pressure parameter with a scan tool. Is the Actual Fuel Rail Pressure parameter more than the specified value? | 10 MPa (1,450 psi) | Go to Step 13 | Go to Step 12 |
| 12 | Prime the fuel manager to 10 psi. Attempt to start the engine while the prime is still above 8 psi. Does the engine start? | Go to Fuel System Diagnosis | Go to Fuel System Diagnosis - High Pressure Side | |
| 13 | IMPORTANT: If there is high resistance in the signal or low reference circuits of the crankshaft position (CKP) sensor the Engine Speed parameter of the scan tool will display a value more than 0. It will not be an accurate measure of engine speed, and can cause an Engine Cranks but does Not Run condition. Test the CKP sensor signal and low reference circuits for high resistance. Refer to Circuit Testing in Wiring Systems.Did you find and correct the condition? | Go to Step 26 | Go to Step 14 | |
| 14 | Inspect for the following conditions: A plugged air filter A collapsed air intake duct The fuel heater is inoperative. If the customer concern is that the engine will not start when ambient temperatures are less than 2-4°C (35-40°F), refer to Fuel Heater Inoperative . A restricted exhaust system-Refer to Symptoms - Engine Exhaust in Engine Exhaust. Did you find and correct the condition? | Go to Step 26 | Go to Diagnostic Aids | |
| 15 | Disconnect the fuel rail pressure (FRP) sensor. Observe the Actual Fuel Rail Pressure parameter on the scan tool. Does the Actual Fuel Rail Pressure parameter measure more than the specified value? | 175 MPa | Go to Step 17 | Go to Step 16 |
| 16 | Test the FRP sensor signal circuit for a short to ground. Refer to Circuit Testing in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 21 | |
| 17 | Test the FRP sensor circuits for high resistance. Refer to Circuit Testing in Wiring Systems. Did you find and correct the condition? | Go to Step 26 | Go to Step 19 | |
| 18 | Test the ignition 1 voltage circuit of the engine control module (ECM) for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Replace the fuse if necessary. Did you find and correct the condition? | Go to Step 26 | Go to Step 20 | |
| 19 | Test for an intermittent or for a poor connection at the FRP sensor. 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 26 | Go to Step 24 | |
| 20 | Clean and tighten the ECM shared ground. Refer to Power and Grounding Component Views in Wiring Systems. Attempt to start the engine. Does the engine start? | Go to Step 26 | Go to Step 21 | |
| 21 | 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 26 | Go to Step 25 | |
| 22 | IMPORTANT: When the fuel injector pressure lines are removed, debris will fall on the fuel injector inlet fitting. Vacuum the debris from the area to prevent the debris from falling in the fuel injector. Replace the fuel injectors on the affected cylinders. Refer to Fuel Injector Replacement (Left) or Fuel Injector Replacement (Right) .Did you complete the replacement? | Go to Step 26 | ||
| 23 | IMPORTANT: Before replacing the fuel filter/heater element housing, inspect the fuel vent screw for damage or cross threading. Replace the vent screw w/O-ring if either condition is found. Replace the fuel filter/heater element housing. Refer to Fuel Filter/Heater Element Housing Replacement .Did you complete the replacement? | Go to Step 26 | ||
| 24 | Replace the FRP sensor. Refer to Fuel Rail Pressure (FRP) Sensor Replacement . Did you complete the replacement? | Go to Step 26 | ||
| 25 | Replace the ECM. Refer to Engine Control Module (ECM) Replacement . Did you complete the replacement? | Go to Step 26 | ||
| 26 | Clear any DTCs with a scan tool. Attempt to start the engine. Does the engine start and continue to run? | Go to Step 27 | Go to Step 2 | |
| 27 | Allow the engine to idle until normal operating temperature is reached. Observe the DTC Information with a scan tool. Are any DTCs displayed? | Go to Diagnostic Trouble Code (DTC) List | System OK |
| IMPORTANT |
|---|
| If there is high resistance in the signal or low reference circuits of the crankshaft position (CKP) sensor the Engine Speed parameter of the scan tool will display a value more than 0. It will not be an accurate measure of engine speed, and can cause an Engine Cranks but does Not Run condition. |
| IMPORTANT |
|---|
| When the fuel injector pressure lines are removed, debris will fall on the fuel injector inlet fitting. Vacuum the debris from the area to prevent the debris from falling in the fuel injector. |
| IMPORTANT |
|---|
| Before replacing the fuel filter/heater element housing, inspect the fuel vent screw for damage or cross threading. Replace the vent screw w/O-ring if either condition is found. |
Engine Cranks but Does Not Run
Fuel System Description
Fuel is drawn by the supply pump through a pre-filter screen in the tank and to the engine through the fuel supply lines. There is no lift pump in the fuel tanks or on the frame. The fuel passes through the base plate of the fuel injector control module (FICM) to cool the module. From the FICM the fuel flows to the fuel filter/heater element housing, which combines a water separator, a prime pump, a fuel heater element and a filter element. The fuel is then delivered to the high-pressure pump. An integrated hand pump is used to prime the fuel system after changing the fuel filter or servicing the fuel system. The fuel injection pump at the front of the engine valley includes the fuel supply pump and the high-pressure pump. If the fuel system is not suppling enough fuel, a driveability concern may occur. If air is being drawn into the fuel injection system, a Cranks But Will Not Run or Hart Start symptom could exist.
Fuel is drawn by the supply pump through a pre-filter screen in the tank and to the engine through the fuel supply lines. There is no lift pump in the fuel tanks or on the frame. The fuel passes through the base plate of the fuel injector control module (FICM) to cool the module. From the FICM the fuel flows to the fuel filter/heater element housing, which combines a water separator, a prime pump, fuel heater element and a filter element. The fuel is then delivered to the high-pressure pump. An integrated hand pump is used to prime the fuel system after changing the fuel filter or servicing the fuel system. The fuel injection pump at the front of the engine valley includes the fuel supply pump and the high-pressure pump. If the fuel system is not suppling enough fuel a driveability concern may occur. If air is being drawn into the fuel injection system, a Cranks But Will Not Run or Hart Start symptom could exist.
The numbers below refer to the step numbers on the diagnostic table.
- 4: The balance rate adjustments are utilized by the ECM only at idle. The balance rates are the fuel adjustments for each individual cylinder based on the variations in engine crankshaft speed. A positive value indicates that fuel is being added to each cylinder event, such as with poor engine compression or a fuel injector that is not flowing enough fuel. A negative value indicates fuel being removed from each cylinder event, such as a fuel injector that is flowing too much fuel. The balance rates will change depending on if the transmission is in Neutral or Drive.
- 5: This step determines if the ECM can control a stable fuel pressure. A high balance rate may be caused by a fuel injector or compression only if the ECM can control fuel pressure.
- 6: The Cylinder Power Balance Test may be performed at any engine speed or load from idle to wide-open throttle (WOT). There is a 5 minute time limit for each test. The ECM and scan tool must both be powered down to reset the timer.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Are any DTCs set other than P0300, P0301-P0308? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3 | |
| 3 | Does the customer concern occur at idle or during tip-in acceleration off-idle? | Go to Step 4 | Go to Step 6 | |
| 4 | Start and run the engine until the engine coolant temperature is more than 82°C (180°F). Turn OFF all accessories. Hold the brake pedal in the fully applied position. A hiss will be noticeable when the brake is fully applied. Place the transmission in Drive. Idle the engine for more than 30 seconds. Record the Balancing Rate Cyl.1-8 parameters from the scan tool while the engine is at idle speed. Repeat steps 2-6 with the transmission in Neutral. Are all of the Balancing Rate parameters within the first specified range in Drive, and the second specified range in Neutral? | 6 mm 3 and +6 mm 3 -4 mm 3 and +4 mm 3 | Go to Step 6 | Go to Step 5 |
| 5 | Graph the Fuel Pressure Regulator. Refer to Fuel Pressure Regulator Diagnosis . Is the fuel pressure regulator graph normal? | Go to Step 7 | Go to Step 9 | |
| 6 | IMPORTANT: The fuel Cylinder Power Balance Test must be performed under the conditions for which the concern occurred. The concern must be duplicated during the test. IMPORTANT: Do not operate the cruise control during this test. Cruise control reactivation after the test may cause a brief extreme increase in engine speed. Observe the cylinder power contribution or other customer concern. Perform the Cylinder Power Balance Test in Special Functions. Do any of the cylinders indicate a different cylinder power contribution than the others, or lessen the customer concern? | Go to Step 7 | System OK | |
| 7 | IMPORTANT: A fuel injector leak into the combustion chamber may result in mechanical damage to the cylinder. If any fuel spray comes out of a glow plug hole during the compression test, replace the fuel injector of the affected cylinder. Perform the Engine Compression Test. Refer to Engine Compression Test in Engine Mechanical - 6.6L.Do any of the cylinders have low compression? | Go to Symptoms - Engine Mechanical in Engine Mechanical - 6.6L | Go to Step 8 | |
| 8 | IMPORTANT: Refer to Injection System Components in Engine Controls Component Views . Failure to correctly identify the cylinder positions may result in the replacement of the wrong fuel injector. Replace the fuel injectors on the cylinders that had poor cylinder power contribution, high balance rates, or a noise/smoke change. Refer to Fuel Injector Replacement (Left) or Fuel Injector Replacement (Right) .Did you complete the replacements? | Go to Step 10 | ||
| 9 | Replace the fuel pressure regulator. Refer to Fuel Pressure Regulator Replacement . Did you complete the replacement? | Go to Step 10 | ||
| 10 | Operate the vehicle under the conditions in which the concern occurred. Does the system operate normally, with no DTCs or symptoms? | System OK | Go to Symptoms - Engine Controls |
| IMPORTANT |
|---|
| The fuel Cylinder Power Balance Test must be performed under the conditions for which the concern occurred. The concern must be duplicated during the test. |
| IMPORTANT |
|---|
| Do not operate the cruise control during this test. Cruise control reactivation after the test may cause a brief extreme increase in engine speed. |
| IMPORTANT |
|---|
| A fuel injector leak into the combustion chamber may result in mechanical damage to the cylinder. If any fuel spray comes out of a glow plug hole during the compression test, replace the fuel injector of the affected cylinder. |
| IMPORTANT |
|---|
| Refer to Injection System Components in Engine Controls Component Views . Failure to correctly identify the cylinder positions may result in the replacement of the wrong fuel injector. |
Fuel Injector Balance Test with Tech 2 (with Automatic Transmission)
The numbers below refer to the step numbers on the diagnostic table.
- 2: If the majority of the balance rates are positive and high, the dual-mass flywheel is causing a harmonic vibration that is affecting the engine fuel control system.
- 3: A dual mass flywheel concern will cause the balance rates to be inaccurate. The transmission concerns must be repaired before any fuel system diagnostic can be performed.
- 4: The balance rates are only to be used to diagnose these specific concerns.
- 5: The balance rate adjustments are utilized by the ECM only at idle. The balance rates are the fuel adjustments for each individual cylinder based on the variations in engine crankshaft speed. A positive value indicates that fuel is being added to each cylinder event, such as with poor engine compression or a fuel injector that is not flowing enough fuel. A negative value indicates fuel being removed from each cylinder event, such as a fuel injector that is flowing too much fuel.
- 6: This step determines if the ECM can control a stable fuel pressure. A high balance rate may be caused by a fuel injector or compression only if the ECM can control fuel pressure.
- 7: The Cylinder Power Balance Test may be performed at any engine speed or load from idle to wide-open throttle. There is a 5 minute time limit for each test. The ECM and scan tool must both be powered down to reset the timer.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls | |
| 2 | Start and run the engine until the engine coolant temperature is more than 82°C (180°F). Turn OFF all accessories. Hold the brake pedal in the fully applied position. A hiss will be noticeable when the brake is fully applied. Idle the engine for more than 30 seconds. Record the Balancing Rate Cyl.1-8 parameters from the scan tool while the engine is at idle speed. Are at least 5 of the Balancing Rate parameters more than the specified value? | +4 mm 3 | Go to Engine Flywheel Replacement (Automatic Transmission) or Engine Flywheel Replacement (Manual Transmission) in Engine Mechanical - 6.6L | Go to Step 3 |
| 3 | Are any DTCs set other than P0300, P0301-P0308? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 4 | |
| 4 | Does the customer concern occur at idle or during tip-in acceleration off-idle? | Go to Step 5 | Go to Step 7 | |
| 5 | Start and run the engine until the engine coolant temperature (ECT) is more than 82°C (180°F). Turn OFF all accessories. Hold the brake pedal in the fully applied position. A hiss will be noticeable when the brake is fully applied. Idle the engine for more than 30 seconds. Record the Balancing Rate Cyl.1-8 parameters from the scan tool while the engine is at idle speed. Are all of the Balancing Rate parameters within the specified range? | 4 mm 3 and +4 mm 3 | Go to Step 7 | Go to Step 6 |
| 6 | Graph the fuel pressure regulator. Refer to Fuel Pressure Regulator Diagnosis . Is the fuel pressure regulator graph normal? | Go to Step 8 | Go to Step 10 | |
| 7 | IMPORTANT: The fuel Cylinder Power Balance Test must be performed under the conditions for which the concern occurred. The concern must be duplicated during the test. IMPORTANT: Do not operate the cruise control during this test. Cruise control reactivation after the test may cause a brief extreme increase in engine speed. Observe the cylinder power contribution or other customer concern. Perform the Cylinder Power Balance Test in Special Functions. Do any of the cylinders indicate a different cylinder power contribution than the others, or lessen the customer concern? | Go to Step 8 | System OK | |
| 8 | IMPORTANT: A fuel injector leak into the combustion chamber may result in mechanical damage to the cylinder. If any fuel spray comes out of a glow plug hole during the compression test, replace the fuel injector of the affected cylinder. Perform the Engine Compression Test. Refer to Engine Compression Test in Engine Mechanical - 6.6LDo any of the cylinders have low compression? | Go to Symptoms - Engine Mechanical in Engine Mechanical - 6.6L | Go to Step 9 | |
| 9 | IMPORTANT: Refer to Injection System Components in Engine Controls Component Views . Failure to correctly identify the cylinder positions may result in the replacement of the wrong fuel injector. Replace the fuel injectors on the cylinders that had poor cylinder power contribution, high balance rates, or a noise/smoke change. Refer to Fuel Injector Replacement (Left) or Fuel Injector Replacement (Right) .Did you complete the replacements? | Go to Step 11 | ||
| 10 | Replace the fuel pressure regulator. Refer to Fuel Pressure Regulator Replacement . Did you complete the replacement? | Go to Step 11 | ||
| 11 | Operate the vehicle under the conditions in which the concern occurred. Does the system operate normally, with no DTCs or symptoms? | System OK | Go to Symptoms - Engine Controls |
| IMPORTANT |
|---|
| The fuel Cylinder Power Balance Test must be performed under the conditions for which the concern occurred. The concern must be duplicated during the test. |
| IMPORTANT |
|---|
| Do not operate the cruise control during this test. Cruise control reactivation after the test may cause a brief extreme increase in engine speed. |
| IMPORTANT |
|---|
| A fuel injector leak into the combustion chamber may result in mechanical damage to the cylinder. If any fuel spray comes out of a glow plug hole during the compression test, replace the fuel injector of the affected cylinder. |
| IMPORTANT |
|---|
| Refer to Injection System Components in Engine Controls Component Views . Failure to correctly identify the cylinder positions may result in the replacement of the wrong fuel injector. |
Fuel Injector Balance Test with Tech 2 (with Manual Transmission)
Description
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 purpose of the I/M Complete System Set Procedure is to satisfy the enable criteria necessary to execute all of the I/M system monitors. When all system monitors are completed, the I/M System Status indicators are set to YES. Perform this procedure when more than one of the I/M System Status indicators are set to NO.
The purpose of this test is to satisfy the enable criteria necessary to execute an Inspection/Maintenance (I/M) system monitor for the Exhaust Gas Recirculation (EGR) system. The system monitor is comprised of the test results from one or more DTCs. This procedure may be used to set the EGR I/M System Status display on the scan tool to YES. The EGR I/M System Status display indicated whether or not the control module has completed the system monitor. The system monitor completes when either all DTCs comprising the monitor run and pass, or any DTC comprising the monitor illuminates the malfunction indicator lamp (MIL). If one of the DTCs comprising the monitor is set and the MIL is not illuminated, the necessary trips are required to illuminate the MIL before the monitor will complete. Once the monitor completes, the EGR I/M System Status display will be updated to YES.
The purpose of this procedure is to satisfy the enable criteria necessary to execute an Inspection/Maintenance (I/M) system monitor for the misfire monitoring system. The system monitor is comprised of the test results from one or more DTCs. This procedure may be used to set the Misfire Monitoring I/M System Status display on the scan tool to YES. The Misfire Monitoring I/M System Status display indicates whether or not the control module has completed the system monitor. The system monitor completes when either all DTCs comprising the monitor run and pass, or any DTC comprising the monitor illuminates the malfunction indicator lamp (MIL). If one of the DTCs comprising the monitor is set and the MIL is not illuminated, the necessary trips are required to illuminate the MIL before the monitor will complete. Once the monitor completes, the Misfire Monitoring I/M System Status display will be updated to YES.
The number below refers to the step number on the diagnostic table.
- 5: This steps checks for a thermostatic switch that completes the circuit.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics | ||||
| 1 | Does the Water In Fuel lamp operate properly? | Go to Step 2 | Go to Water-in-Fuel Lamp Always On in Instrument Panel, Gages, and Console | |
| 2 | Disconnect the fuel heater harness connector from the top of the fuel filter/heater element housing. Turn ON the ignition with the engine OFF. Probe the fuel heater ignition 1 voltage circuit with a test lamp connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate? | Go to Step 3 | Go to Step 6 | |
| 3 | Probe the fuel heater ground circuit at the fuel filter/heater element housing with a test lamp connected to B+. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate? | Go to Step 4 | Go to Step 8 | |
| 4 | Remove the fuel filter from the fuel filter/heater element housing. Test the ignition 1 voltage circuit and the ground circuit for an open in the fuel filter/heater element housing. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems. Did either circuit test open? | Go to Step 9 | Go to Step 5 | |
| 5 | Remove the fuel filter/heater element housing from the vehicle. Connect the ignition 1 voltage circuit of the fuel heater to battery voltage source and connect the ground circuit of the fuel heater to the ground of the voltage source. Cool the sensor part of the fuel heater with ice. Observe the heating element. Does the thermostatic switch turn ON when the temperature is within the specified range? | 8.4 to +15.4°C (+16.9 to +59.8°F) | Go to Step 11 | Go to Step 10 |
| 6 | Repair the open in the ignition 1 voltage circuit between the fuel filter/heater element housing and the fuse. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | ||
| 7 | Repair the short to ground on the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | ||
| 8 | Repair the open in the ground circuit between the fuel filter/heater element housing and chassis ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 11 | ||
| 9 | Replace the fuel filter/heater element housing. Refer to Fuel Filter/Heater Element Housing Replacement . Did you complete the replacement? | Go to Step 11 | ||
| 10 | Replace the fuel heater. Refer to Fuel Filter/Heater Element Housing Replacement . Did you complete the replacement? | Go to Step 11 | ||
| 11 | Operate the vehicle under which the problem was noted. Does the system operate properly? | System OK | Go to Step 1 | |
Fuel Heater Inoperative
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests for a fuel heater thermostatic switch that is stuck ON.
- 3: This steps tests for a thermostatic switch that completes the circuit.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics | ||||
| 1 | Does the Water In Fuel lamp operate properly? | Go to Step 2 | Go to Water-in-Fuel Lamp Always On in Instrument Panel, Gages, and Console | |
| 2 | Remove the fuel filter/heater element housing from the vehicle. Refer to Fuel Filter/Heater Element Housing Replacement . With the fuel filter/heater element housing at room temperature, above 15°C (59°F), connect a DMM between the fuel heater ground circuit and the fuel heater voltage supply circuit. Does the DMM display the specified value? | Go to Step 3 | Go to Step 4 | |
| 3 | IMPORTANT: The fuel filter/heater element housing must be cooled to below 8°C (46°F) before the thermostatic switch will turn ON. Cool the fuel filter/heater element housing. Connect the fuel heater voltage supply circuit to battery voltage, and the fuel heater ground circuit to a good ground. Observe the heating element. Does the thermostatic switch turn ON and heat the element when the temperature is within the specified range? | 8-15°C (46-59°F) | Go to Step 5 | Go to Step 4 |
| 4 | Replace the fuel filter/heater element housing. Refer to Fuel Filter/Heater Element Housing Replacement . Did you complete the replacement? | Go to Step 5 | ||
| 5 | Operate the vehicle under which the condition was noted. Does the system operate properly? | System OK | Go to Step 1 | |
| IMPORTANT |
|---|
| The fuel filter/heater element housing must be cooled to below 8°C (46°F) before the thermostatic switch will turn ON. |
Fuel Heater Always On