Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests if the concern is active. You should hear a clicking sound when the HPL solenoid is commanded ON and OFF. Repeat the commands as necessary.
- 4: The AF lock-off relay also supplies voltage to the low pressure lock-off (LPL) solenoid. An open circuit between the AF lock-off relay and the splice will cause P2665 to also set.
- 5: This step verifies that the control module is providing ground to the HPL solenoid.
- 6: This step tests if a ground is constantly being applied to the HPL solenoid.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | Turn ON the ignition, with the engine OFF. Command the high pressure lock-off (HPL) solenoid ON and OFF with a scan tool. Listen for audible operation of the solenoid. Does the HPL solenoid respond to the scan tool commands? | Go to Step 3 | Go to Step 4 |
| 3 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions |
| 4 | Turn OFF the ignition. Disconnect harness connector of the HPL solenoid. Refer to High Pressure Lock-Off (HPL) Solenoid Replacement . Turn ON the ignition, with the engine OFF. Probe the ignition voltage circuit of the HPL solenoid with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 5 | Go to Step 9 |
| 5 | Connect a test lamp between the control circuit of the HPL solenoid and the ignition voltage circuit of the HPL solenoid. Command the HPL solenoid ON and OFF with a scan tool. Does the test lamp turn ON and OFF with each command? | Go to Step 10 | Go to Step 6 |
| 6 | Does the test lamp remain illuminated with each command? | Go to Step 8 | Go to Step 7 |
| 7 | Test the control circuit of the HPL solenoid for an open or for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 11 |
| 8 | Test the control circuit of the HPL solenoid 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 14 | Go to Step 13 |
| 9 | Test the ignition voltage circuit for an open or short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Fuel Lock-Off Relay Diagnosis |
| 10 | Inspect for poor connections at the HPL solenoid. 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 14 | Go to Step 12 |
| 11 | Inspect for poor connections at the harness connector of the powertrain control module (PCM). 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 14 | Go to Step 13 |
| 12 | Replace the HPL solenoid. Refer to High Pressure Lock-Off (HPL) Solenoid Replacement . Did you complete the replacement? | Go to Step 14 | |
| 13 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT . Did you complete the replacement? | Go to Step 14 | |
| 14 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 15 |
| 15 | 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 |
DTC P0005
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the condition is active.
- 4: This step tests for a short to ground on the AF enable circuit.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Fuel Injection Control Module Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | IMPORTANT: Verify that there is adequate fuel in the CNG fuel tank before proceeding. Turn ON the ignition, with the engine OFF. Observe the Fuel Mode Command parameter with a scan tool. Does the scan tool display ALT FUEL? | Go to Step 3 | Go to Step 4 |
| 3 | Observe the Freeze Frame and/or the Failure records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Intermittent Conditions |
| 4 | Turn OFF the ignition. Disconnect the fuel injection control module (FICM). Refer to Fuel Injection Control Module Replacement . Probe the AF enable circuit with a test lamp connected to B+. Does the test lamp illuminate? | Go to Step 7 | Go to Step 5 |
| 5 | Turn ON the ignition. Command the AF enable circuit ON and OFF with a scan tool. Observe the test lamp. Does the test lamp respond to the scan tool commands? | Go to Step 9 | Go to Step 6 |
| 6 | Test the AF enable circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
| 7 | Test the AF enable 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 12 | Go to Step 10 |
| 8 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 |
| 9 | Test for an intermittent and for a poor connection at the FICM. 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 12 | Go to Step 11 |
| 10 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT . Did you complete the replacement? | Go to Step 12 | |
| 11 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 12 | |
| 12 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 |
| 13 | 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 |
| IMPORTANT |
|---|
| Verify that there is adequate fuel in the CNG fuel tank before proceeding. |
DTC P0148
The numbers below refer to the step numbers on the diagnostic table.
- 5: The PCM will adjust fuel trim based upon fuel rail pressure (FRP) sensor values. A false high pressure FRP value will cause the PCM to inaccurately lean the fuel trim.
- 8: If conditions were not corrected, a worn cam, worn intake or exhaust valves, or other engine mechanical failure may be the problem.
- 9: The fuel injector control module (FICM) uses the Injector Monitor circuits in order to calculate CNG fuel injector amperage. An inaccurate even bank circuit amperage reading will cause a cylinder #6 misfire, bank 1 sensor 1 voltage to be near 900 mV and bank 2 sensor 1 voltage to be near 0 mV. An inaccurate odd bank circuit amperage reading will cause a cylinder #1 misfire, bank 1 sensor 1 voltage to be near 0 mV and bank 2 sensor 1 voltage to be near 900 mV.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Is this vehicle equipped with the dedicated compressed natural gas (CNG) option (KL8)? | Go to Step 4 | Go to Step 3 | |
| 3 | Review the Freeze Frame/Failure Records or interview the vehicle operator in order to determine if the DTC set while operating on CNG. Did this DTC set while operating on CNG? | Go to Step 4 | Go to DTC P0171 OR P0174 in Engine Controls. | |
| 4 | IMPORTANT: If any DTCs other than P0171 or P0174 are set, refer to those DTCs before continuing. Install the scan tool. IMPORTANT: Ensure the engine is operating on CNG during all testing. Start and idle the engine at the normal operating temperature in Closed Loop. Record the long term fuel trim. Turn OFF the ignition and wait 30 seconds. Turn ON the ignition, with the engine OFF. Review the Freeze Frame/Failure Records and record the displayed data for this DTC. Does the scan tool indicate that the long term fuel trim is greater than the specified value? | 28% | Go to Step 5 | Go to Diagnostic Aids |
| 5 | Operate the engine at idle. Observe the fuel rail pressure (FRP) sensor parameter with a scan tool. Does the scan tool display fuel rail pressure more than the value specified? | 620 kPa (90 psi) | Go to DTC P0191 | Go to Step 6 |
| 6 | Observe the scan tool display for the following conditions: Sensor 1 heated oxygen sensor (HO2S) voltage of one bank fixed very high Sensor 1 HO2S voltage of the other bank fixed very low A cylinder #1 OR a cylinder #6 misfire Are ALL of the above conditions present? | Go to Step 9 | Go to Step 7 | |
| 7 | Turn OFF the engine. Visually and physically inspect the following items: The vacuum hoses for splits, kinks, and proper connections-Refer to the Underhood Emission Hose Routing label. The HO2S sensors for proper installation The HO2S electrical connectors and the wires are secure, and not contacting the exhaust system. Test for continuity between the HO2S signal circuit and the low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 | |
| 8 | Operate the engine at idle. Inspect for any missing, loose, or leaking exhaust components forward of the HO2S. Inspect for vacuum leaks at the intake manifold, throttle body, and injector O-rings. Inspect the air induction system and the air intake ducts for leaks. Inspect the crankcase ventilation system for leaks. Refer to Crankcase Ventilation System Inspection/Diagnosis in Engine Mechanical. Did you find and correct the condition? | Go to Step 12 | Go to SYMPTOMS - ENGINE MECHANICAL in Engine Mechanical. | |
| 9 | Turn the ignition OFF. Disconnect the fuel injector control module (FICM) connector. Refer to Fuel Injection Control Module Replacement . Test the odd bank or even bank injector monitor circuit for an open or high resistance condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | |
| 10 | Test for an intermittent and for a poor terminal connection at the FICM. 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 12 | Go to Step 11 | |
| 11 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 12 | IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 | |
| 13 | 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 |
| IMPORTANT |
|---|
| If any DTCs other than P0171 or P0174 are set, refer to those DTCs before continuing. |
| IMPORTANT |
|---|
| Ensure the engine is operating on CNG during all testing. |
| IMPORTANT |
|---|
| After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. |
DTC P0171 or P0174
The numbers below refer to the step numbers on the diagnostic table.
- 5: If the cause of the DTC is not found and corrected, refer to Fuel System Diagnosis for a possible fuel related condition.
- 6: On KL6 equipped vehicles, an EVAP canister that is saturated will cause a rich condition. If the condition is not found, a worn cam, worn intake or exhaust valves, or other engine mechanical failure may be the cause of the DTC.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | IMPORTANT: If any DTCs other than P0172 or P0175 are set, refer to those DTCs before continuing. Install scan tool. Start and idle the engine at the normal operating temperature in Closed Loop. Record the long term fuel trim data. Turn OFF the engine. Turn ON ignition, with the engine OFF. Review the Freeze Frame/Failure Records, and record the displayed data for this DTC. Does the scan tool indicate that the long term fuel trim is less than the specified value? | 15% | Go to Step 3 | Go to Diagnostic Aids |
| 3 | Operate engine at idle. Observe HO2S parameters with a scan tool. Does the scan tool indicate that the values are within the specified range and fluctuating? | 200-800 mV | Go to Step 4 | Go to Step 5 |
| 4 | Turn OFF the engine. Visually and physically inspect the following items: The evaporative emission (EVAP) lines and components, if equipped, for damage or blockage - Refer to EVAPORATIVE EMISSIONS (EVAP) HOSE ROUTING DIAGRAM in Engine Controls. The inlet screen of the mass air flow (MAF) sensor for blockage The vacuum hoses for splits, kinks, and proper connections-Refer to the Underhood Emission Hose Routing label. The air intake duct for being collapsed or restricted The air filter for being dirty or restricted Check for objects blocking the throttle body. Did you find and correct the condition? | Go to Step 7 | Go to Step 6 | |
| 5 | Turn OFF the engine. Inspect the heated oxygen sensor (HO2S) for proper installation. Inspect to ensure that the electrical connectors and the wires are secure and not contacting the exhaust system. Test for continuity between the signal circuit and the low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 7 | Go to FUEL SYSTEM DIAGNOSIS in Engine Controls. | |
| 6 | Inspect for the following: Excessive fuel in the crankcase (KL6 only) Proper operation of the gasoline fuel pressure regulator (KL6 only) - Refer to FUEL SYSTEM DIAGNOSIS in Engine Controls. All compressed natural gas (CNG) fuel injectors are functioning properly. Refer to Fuel Injector Coil Test . All gasoline fuel injectors are functioning properly. Refer to FUEL INJECTOR COIL TEST in Engine Controls. Did you find and correct the condition? | Go to Step 7 | Go to SYMPTOMS - ENGINE MECHANICAL in Engine Mechanical. | |
| 7 | IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 8 | |
| 8 | 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 |
| IMPORTANT |
|---|
| If any DTCs other than P0172 or P0175 are set, refer to those DTCs before continuing. |
| IMPORTANT |
|---|
| After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. |
DTC P0172 or P0175
The numbers below refer to the step numbers on the diagnostic table.
- 4: This step tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
- 8: This step tests the signal circuit of the FTT sensor for a short to another 5-volt reference circuit.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the Fuel Temperature sensor parameter with a scan tool. Does the scan tool indicate that the fuel tank temperature (FTT) is near the specified value? | 5 V | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Diagnostic Aids | |
| 4 | Turn OFF the ignition. Disconnect the FTT sensor. Refer to High Pressure Lock-Off (HPL) Solenoid Replacement . IMPORTANT: If the fuse opens, repair the short to voltage on the FTT signal circuit. Connect a 3-amp fused jumper wire between the signal circuit of the FTT sensor and the low reference circuit of the FTT sensor. Turn ON the ignition, with the engine OFF. Observe the FTT parameter with a scan tool. Does the scan tool indicate that the FTT is at the specified value? | 0 V | Go to Step 7 | Go to Step 5 |
| 5 | Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit of the FTT sensor and a good ground. Turn ON the ignition, with the engine OFF. Observe the Fuel Temperature parameter with a scan tool. Does the scan tool indicate that the FTT is at the specified value? | 0 V | Go to Step 9 | Go to Step 6 |
| 6 | Test the signal circuit of the FTT sensor for an open circuit or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 | |
| 7 | Test for an intermittent and for a poor connection at the FTT sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | |
| 8 | Test for an intermittent and for a poor connection at the fuel injector control module (FICM). 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 12 | Go to Step 11 | |
| 9 | Repair the low reference circuit of the FTT sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and complete the repair? | Go to Step 12 | ||
| 10 | Replace the FTT sensor. The FTT sensor is not serviceable separately from the high pressure lock-off (HPL). Refer to High Pressure Lock-Off (HPL) Solenoid Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 11 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 12 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 | |
| 13 | 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 | |
| IMPORTANT |
|---|
| If the fuse opens, repair the short to voltage on the FTT signal circuit. |
DTC P0183
The number below refers to the step number on the diagnostic table.
- 4: This step tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the FRT sensor parameter with a scan tool. Does the scan tool indicate that the fuel rail temperature (FRT) is near the specified value? | 5 V | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Diagnostic Aids | |
| 4 | Turn OFF the ignition. Disconnect the FRT sensor. Refer to Fuel Rail Temperature (FRT) Sensor Replacement . IMPORTANT: If the fuse opens, repair the short to voltage on the FRT signal circuit. Connect a 3-amp fused jumper wire between the signal circuit of the FRT sensor and the low reference circuit of the FRT sensor. Turn ON the ignition, with the engine OFF. Observe the FRT parameter with a scan tool. Does the scan tool indicate that the FRT is at the specified value? | 0 V | Go to Step 8 | Go to Step 5 |
| 5 | Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit of the FRT sensor and a good ground. Turn ON the ignition, with the engine OFF. Observe the FRT parameter with a scan tool. Does the scan tool indicate that the FRT is at the specified value? | 0 V | Go to Step 7 | Go to Step 6 |
| 6 | Test the signal circuit of the fuel tank temperature (FTT) sensor for an open circuit or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 7 | Test the low reference circuit of the FTT sensor for an open circuit or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 8 | Test for an intermittent and for a poor connection at the FTT sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | |
| 9 | Test for an intermittent and for a poor connection at the fuel injector control module (FICM). 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 12 | Go to Step 11 | |
| 10 | Replace the FRT sensor. Refer to Fuel Rail Temperature (FRT) Sensor Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 11 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 12 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 | |
| 13 | 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 | |
| IMPORTANT |
|---|
| If the fuse opens, repair the short to voltage on the FRT signal circuit. |
DTC P0188
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the condition is present.
- 4: This step determines if the low pressure lock-off (LPL) solenoid is functioning.
- 5: This step tests the low reference circuit of the FRP sensor.
- 6: This step determines if the 5-volt reference circuit is the cause of the condition. The DMM should display 5.0 volts across the test lamp.
- 7: This step tests the signal circuit of the FRP sensor.
- 9: This step verifies that a mechanical fuel system condition is not the cause of the concern. A fuel pressure regulator condition may cause this DTC to set.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the Fuel Rail Pressure (FRP) data display with a scan tool. Does the scan tool display the FRP sensor pressure within the specified range? | 206-1 620 kPa (30-90 psi) | Go to Step 3 | Go to Step 4 |
| 3 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Intermittent Conditions | |
| 4 | Turn ON the ignition, with the engine OFF. Command the low pressure lock-off (LPL) ON and OFF with a scan tool. Listen for operation of the LPL. Can operation of the LPL be heard? | Go to Step 5 | Go to DTC P2665 | |
| 5 | Disconnect the FRP sensor. Refer to Fuel Rail Pressure (FRP) Sensor Replacement . Probe the low reference circuit of the FRP sensor with a test lamp connected to B+. Is the test lamp illuminated? | Go to Step 6 | Go to Step 10 | |
| 6 | Probe the 5-volt reference circuit of the FRP sensor with a test lamp to ground. Measure the voltage drop across the test lamp with a DMM. Refer to MEASURING VOLTAGE DROP in Wiring Systems. Is the voltage at the specified value? | 5 V | Go to Step 7 | Go to Step 11 |
| 7 | Connect a 3-amp fused jumper wire between the signal circuit and the 5-volt reference circuit of the FRP sensor. Observe the FRP sensor data display with a scan tool. Does the scan tool display FRP sensor voltage more than the value specified? | 4.95 V | Go to Step 9 | Go to Step 8 |
| 8 | Test the signal circuit of the FRP sensor for an open or excessive resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 9 | IMPORTANT: Return to this diagnostic procedure, after performing the Fuel System Diagnosis. Perform the Fuel System Diagnosis procedure. Refer to Fuel System Diagnosis .Did find and correct the condition? | Go to Step 15 | Go to Step 13 | |
| 10 | Test the low reference circuit of the FRP sensor for an open or excessive resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 11 | Test the 5-volt reference circuit of the FRP sensor for excessive resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 12 | Inspect for proper terminal contact at the harness connector of the powertrain control module (PCM). 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 | |
| 13 | Replace the FRP sensor. Refer to Fuel Rail Pressure (FRP) Sensor Replacement . Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT . Did you complete the replacement? | Go to Step 15 | ||
| 15 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 16 | |
| 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 | |
| IMPORTANT |
|---|
| Return to this diagnostic procedure, after performing the Fuel System Diagnosis. |
DTC P0191
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the condition is present.
- 4: This step determines if the FRP sensor is the cause of the condition.
- 5: This step determines if the 5-volt reference circuit is the cause of the condition.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the Fuel Rail Pressure (FRP) data display with a scan tool. Does the scan tool display the FRP sensor voltage less than the specified value? | 0.1 V | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Intermittent Conditions | |
| 4 | Disconnect the FRP sensor. Refer to Fuel Rail Pressure (FRP) Sensor Replacement . Connect a 3-amp fused jumper wire between the signal circuit and the 5-volt reference circuit of the FRP sensor. Observe the FRP sensor data display with a scan tool. Does the scan tool display the FRP sensor voltage more than the specified value? | 4.95 V | Go to Step 8 | Go to Step 5 |
| 5 | Remove the fused jumper wire. Measure the voltage from the 5-volt reference circuit of the FRP sensor with a DMM. Is the voltage more than the specified value? | 4.95 V | Go to Step 6 | Go to Step 7 |
| 6 | Test the FRP sensor signal circuit for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 7 | Test for an open or a short to ground on the 5-volt reference circuit of the FRP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 8 | Inspect for proper terminal contact at the harness connector of 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 12 | Go to Step 10 | |
| 9 | Inspect for proper terminal contact at the harness connector of the powertrain control module (PCM). 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 12 | Go to Step 11 | |
| 10 | Replace the FRP sensor. Refer to Fuel Rail Pressure (FRP) Sensor Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 11 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT . Did you complete the replacement? | Go to Step 12 | ||
| 12 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 | |
| 13 | 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 | |
DTC P0192
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the condition is present.
- 4: This step determines if a shorted signal circuit is the cause of the condition.
- 5: This step determines if a shorted 5-volt reference circuit is the cause of the condition.
- 6: This step determines if an open sensor ground circuit is the cause of the condition.
- 10: The Fuel System Diagnosis should be performed prior to replacement of the FRP sensor. The fuel system diagnostic procedure will determine if excessive fuel pressure is the cause of the condition.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the fuel rail pressure (FRP) data display with a scan tool. Does the scan tool display the FRP sensor voltage more than the specified value? | 4.9 V | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Intermittent Conditions | |
| 4 | Disconnect the FRP sensor. Observe the FRP sensor data display with a scan tool. Does the scan tool display the FRP sensor voltage less than the specified value? | 0.05 V | Go to Step 5 | Go to Step 7 |
| 5 | Measure the voltage from the 5-volt reference circuit of the FRP sensor with a DMM. Does the DMM display a voltage more than the specified value? | 5.2 V | Go to Step 8 | Go to Step 6 |
| 6 | Probe the ground circuit of the FRP sensor with a test lamp connected to B+. Does the test lamp illuminate? | Go to Step 10 | Go to Step 9 | |
| 7 | Test the signal circuit of the FRP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 | |
| 8 | Test the 5-volt reference circuit of the FRP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 | |
| 9 | Test the ground circuit of the FRP sensor for an open or high resistance condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11 | |
| 10 | Inspect for proper terminal contact at the harness connector of 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 13 | Go to Fuel System Diagnosis | |
| 11 | Inspect for proper terminal contact at the harness connector of the powertrain control module (PCM). 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 13 | Go to Step 12 | |
| 12 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT . Did you complete the replacement? | Go to Step 13 | ||
| 13 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 14 | |
| 14 | 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 | |
DTC P0193
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step verifies that a condition exists.
- 4: The step determines if the condition occurs during gasoline operation. If the vehicle misfires while on gasoline, then the condition is between the FICM and the gasoline fuel injector.
- 6: This step tests the control circuit between the PCM and the FICM. The test lamp should blink while the engine is cranking. The AF fuel mode relay must be removed in order to prevent a fuel system switch-over.
- 9: This step tests the injector control circuit between the AF injector relay and the PCM. The test lamp should blink while the engine is cranking.
- 13: This step verifies that an ignition voltage is supplied to the gasoline fuel injector. If the ignition voltage circuit is open DTC P0200 will set while operating on gasoline.
- 14: This step tests the injector control circuit between the gasoline fuel injector and the AF injector relay. The test lamp should blink while the engine is running.
- 16: This step tests the ignition voltage circuit to the AF injector relay. If the relay does not switch during gasoline operation, DTC P0200 will set.
- 17: This step tests the ground circuit to the AF injector relay. If the relay does not switch during gasoline operation, DTC P0200 will set.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Fuel Injection Control Module Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | Clear the DTCs with a scan tool. Idle the engine at the normal operating temperature. Monitor the misfire current counters with a scan tool. Are any of the misfire current counters incrementing? | Go to Step 6 | Go to Step 3 |
| 3 | Is this vehicle equipped with the bi-fuel option (KL6)? | Go to Step 4 | Go to Step 5 |
| 4 | IMPORTANT: Verify that the gasoline fuel level is above 10 percent in order to prevent misdiagnosis. The misfire counters may not increment if the gasoline fuel level is below 10 percent. Force a fuel system switch-over to gasoline with the scan tool if necessary to operate the engine on gasoline. Idle the engine at the normal operating temperature. Monitor the misfire current counters with a scan tool. Are any of the misfire current counters incrementing? | Go to Step 13 | Go to Step 5 |
| 5 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 6 | Go to Diagnostic Aids |
| 6 | Turn OFF the ignition. IMPORTANT: Removal of the AF fuel mode relay may cause other DTCs to set. Remove the AF fuel mode relay (KL6 only). Disconnect the harness connector of the fuel injector control module (FICM). Probe the injector control circuit from the powertrain control module (PCM), which displays the highest number of misfire current counters, with a test lamp connected to B+. Crank the engine, while observing the test lamp. Does the test lamp blink? | Go to Step 21 | Go to Step 7 |
| 7 | Does the test lamp remain illuminated? | Go to Step 12 | Go to Step 8 |
| 8 | Is this vehicle equipped with the bi-fuel option (KL6)? | Go to Step 9 | Go to Step 11 |
| 9 | Turn OFF the ignition. Disconnect the appropriate AF injector relay. Turn ON the ignition, with the engine OFF. Probe the fuel injector control circuit from the PCM, with a test lamp connected to B+. Crank the engine, while observing the test lamp. Does the test lamp blink? | Go to Step 10 | Go to Step 11 |
| 10 | Test the control circuit of the fuel injector for an open or a short to voltage between the relay and the fuel injector. Did you find and correct the condition? | Go to Step 31 | Go to Step 20 |
| 11 | Test the control circuit of the fuel injector for an open or a short to voltage between the following: PCM and the FICM (KL8) PCM and the AF injector relay (KL6) Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 22 |
| 12 | Test the fuel injector control circuit for a short to ground between the following: PCM and the FICM (KL8) PCM and the AF injector relay (KL6) AF injector relay and FICM (KL6) AF injector relay and the gasoline fuel injector (KL6) Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 30 |
| 13 | Turn OFF the ignition. Disconnect the harness connector of the gasoline fuel injector which displays the highest level of misfire. Probe the ignition voltage circuit of the gasoline fuel injector with a test lamp connected to a good ground. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? | Go to Step 14 | Go to Step 24 |
| 14 | Probe the control circuit of the gasoline fuel injector with a test lamp connected to B+. Start and idle the engine. Force a fuel system switch-over to gasoline with the scan tool. Observe the test lamp. Does the test lamp blink? | Go to Step 19 | Go to Step 15 |
| 15 | Does the test lamp remain illuminated? | Go to Step 23 | Go to Step 16 |
| 16 | Turn OFF the ignition. Remove the appropriate AF injector relay. Turn ON the ignition, with the engine OFF. Probe the ignition positive circuit of the AF relay coil with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 17 | Go to Step 25 |
| 17 | Probe the ground circuit of the AF injector relay coil with a test lamp connected to B+. Start and idle the engine. Force a fuel system switch-over to gasoline with the scan tool. Does the test lamp illuminate? | Go to Step 18 | Go to Step 26 |
| 18 | Test the control circuit of the fuel injector for an open, or a short to voltage between the gasoline fuel injector and the relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 20 |
| 19 | Test for an intermittent and for a poor connection at the gasoline fuel injector. Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 28 |
| 20 | Test for an intermittent and for a poor connection at the AF injector relay. Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 27 |
| 21 | Test for an intermittent and for a poor connection at the FICM. Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 29 |
| 22 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 31 | Go to Step 30 |
| 23 | Repair the short to ground on the control circuit of the gasoline fuel injector, between the injector and the AF injector relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 31 | |
| 24 | IMPORTANT: The fuse also supplies voltage to the ignition coil modules. If the fuse is open, inspect all related circuits and components for a short to ground. Refer to Circuit Testing in Wiring Systems. Repair the ignition 1 voltage circuit of the fuel injector for an open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you complete the repair? | Go to Step 31 | |
| 25 | Repair the ignition 1 voltage circuit of the AF injector relay coil for an open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 31 | |
| 26 | Repair the ground circuit of the AF injector relay coil for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 31 | |
| 27 | Replace the AF injector relay. Did you complete the replacement? | Go to Step 31 | |
| 28 | Replace the gasoline fuel injector. Refer to Fuel Injector Replacement . Did you complete the replacement? | Go to Step 31 | |
| 29 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 31 | |
| 30 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT . Did you complete the replacement? | Go to Step 31 | |
| 31 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 32 |
| 32 | 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 |
| IMPORTANT |
|---|
| Verify that the gasoline fuel level is above 10 percent in order to prevent misdiagnosis. The misfire counters may not increment if the gasoline fuel level is below 10 percent. |
| IMPORTANT |
|---|
| Removal of the AF fuel mode relay may cause other DTCs to set. |
| IMPORTANT |
|---|
| The fuse also supplies voltage to the ignition coil modules. If the fuse is open, inspect all related circuits and components for a short to ground. Refer to Circuit Testing in Wiring Systems. |
DTC P0200
System Description
The powertrain control module (PCM) uses information from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor in order to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the PCM is able to detect misfire events.
The numbers below refer to the step numbers on the diagnostic table.
- 5: This step determines if the engine is misfiring while operating on the gasoline fuel system.
- 7: If the Misfire Current Counters are incrementing, but the engine is NOT misfiring, this indicates a mechanical condition. For example, an accessory drive belt could cause this condition.
- 8: This step verifies that the Crankshaft Variation Learn Procedure is performed. A crankshaft variation that is not learned may cause the misfire counters to increment.
- 10: The spark should be consistent when you test the spark at the spark plug wires. The presence of few sparks then nothing indicates no spark.
- 14: A misfiring cylinder may cause more than one misfire counter to increment. Diagnose the fuel injector circuit of the cylinder that displays the highest level of misfire.
- 20: A severe misfire can damage the catalytic converter. This step verifies that the catalytic convertors are operating correctly.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the DTC information with a scan tool. Are there any other DTCs set? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3 | |
| 3 | Start the engine. Clear the DTCs with a scan tool. Allow the engine to reach operating temperature. Observe the Misfire Current Counters with a scan tool. Are any of the Misfire Current Counters incrementing? | Go to Step 7 | Go to Step 4 | |
| 4 | Is the vehicle equipped with the bi-fuel option (KL6)? | Go to Step 5 | Go to Step 6 | |
| 5 | Force a switch over to gasoline with the scan tool output controls function. Observe the Misfire Current Counters with a scan tool. Are any of the Misfire Current Counters incrementing? | Go to DTC P0200 | Go to Step 6 | |
| 6 | Observe the Freeze Frame and the Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame, and the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 7 | Go to Diagnostic Aids | |
| 7 | Is the engine misfiring? | Go to Step 9 | Go to Step 8 | |
| 8 | Perform the Crankshaft Variation Learn Procedure. Refer to CKP System Variation Learn Procedure in Engine Controls. Start the engine. Observe the Misfire Current Counters with a scan tool. Are any of the Misfire Current Counters incrementing? | Go to SYMPTOMS - ENGINE MECHANICAL in Engine Mechanical. | Go to Step 21 | |
| 9 | Observe the Misfire Current Counters with a scan tool. Is there only one Misfire Current Counter incrementing? | Go to Step 10 | Go to Step 16 | |
| 10 | Turn OFF the ignition. Disconnect the spark plug wire from the spark plug that indicates a misfire. Refer to SPARK PLUG WIRE REPLACEMENT in Engine Controls. Connect the J 26792 Spark Tester to the spark plug wire and a good ground. Start and idle the engine. Does the spark tester spark and is the spark consistent? | Go to Step 12 | Go to Step 11 | |
| 11 | Turn OFF the ignition. Remove the spark plug wire from the cylinder that indicates a misfire. Refer to SPARK PLUG WIRE REPLACEMENT in Engine Controls. Measure the resistance of the spark plug wire with a DMM. Is the resistance less than the specified value? | 625 ohm Per 30 cm (Per Foot) | Go to ELECTRONIC IGNITION (EI) SYSTEM DIAGNOSIS in Engine Controls. | Go to Step 18 |
| 12 | Remove the spark plug from the cylinder that indicates a misfire. Refer to SPARK PLUG REPLACEMENT in Engine Controls. IMPORTANT: If the spark plug is gas, coolant, or oil fouled, determine the cause of the fouling. Refer to DTC P0172 or P0175 in Engine Controls for spark plugs that are gasoline fouled. Refer to SYMPTOMS - ENGINE MECHANICAL in Engine Mechanical for spark plugs that are coolant or oil fouled. Inspect the spark plug. Refer to Spark Plug Inspection in Engine Controls. Did you find and correct the condition? | Go to Step 19 | Go to Step 13 | |
| 13 | Swap the suspected spark plug with another cylinder that is operating correctly. Start the engine. Operate the engine within the conditions that the misfire occurred. Monitor the Misfire Current Counters with a scan tool. Did the misfire move with the spark plug? | Go to Step 17 | Go to Step 14 | |
| 14 | IMPORTANT: Make sure all the injectors operate. High resistance in an injector circuit causes the injector to be inoperative without setting a fuel injector DTC. Return to this diagnostic after you complete the Fuel Injector Coil Test. Perform the Fuel Injector Coil Test. Refer to Fuel Injector Coil Test .Did you find and correct the condition? | Go to Step 19 | Go to Step 15 | |
| 15 | Perform the Fuel System Diagnosis. Refer to Fuel System Diagnosis . Did you find and correct the condition? | Go to Step 19 | Go to SYMPTOMS - ENGINE MECHANICAL in Engine Mechanical. | |
| 16 | Inspect or test for the following conditions: Inspect the vacuum hoses for splits, kinks, and the correct connections. Inspect for vacuum leaks at the throttle body and at the intake manifold. Inspect the powertrain control module (PCM) grounds for being clean, tight, and in the correct location. Test for the correct fuel pressure. Refer to Fuel System Diagnosis . Inspect for faulty spark plug wires. Refer to SPARK PLUG WIRE INSPECTION in Engine Controls. Inspect for fouled or damaged spark plugs. Refer to SPARK PLUG INSPECTION in Engine Controls. Inspect the exhaust system for restrictions. Refer to RESTRICTED EXHAUST in Engine Exhaust. Did you find and correct the condition? | Go to Step 19 | Go to SYMPTOMS - ENGINE MECHANICAL in Engine Mechanical. | |
| 17 | Replace the spark plug. Refer to SPARK PLUG REPLACEMENT in Engine Controls. Did you complete the replacement? | Go to Step 19 | ||
| 18 | Replace the spark plug wire. Refer to SPARK PLUG WIRE REPLACEMENT in Engine Controls. Did you complete the replacement? | Go to Step 19 | ||
| 19 | Was the customers concern that the was malfunction indicator lamp (MIL) flashing? | Go to Step 20 | Go to Step 21 | |
| 20 | Operate the vehicle at the specified value for 4 minutes. Operate the vehicle within the Conditions for Running the DTC P0420 or P0430 as specified in the supporting text. Refer to DTC P0420 OR P0430 (WITH HP2) or DTC P0420 OR P0430 (WITHOUT HP2) . Does the DTC run and pass? | 2,500 RPM | Go to Step 21 | Go to DTC P0420 OR P0430 (WITH HP2) or DTC P0420 OR P0430 (WITHOUT HP2) in Engine Controls. |
| 21 | Use the scan tool in order to clear the DTCs. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. Does the DTC run and pass? | Go to Step 22 | Go to Step 2 | |
| 22 | With a scan tool, select Capture Info in order to observe the stored information. Does the scan tool display any DTCs that you have not diagnosed? | Go to Diagnostic Trouble Code (DTC) List | System OK |
| IMPORTANT |
|---|
| If the spark plug is gas, coolant, or oil fouled, determine the cause of the fouling. Refer to DTC P0172 or P0175 in Engine Controls for spark plugs that are gasoline fouled. Refer to SYMPTOMS - ENGINE MECHANICAL in Engine Mechanical for spark plugs that are coolant or oil fouled. |
| IMPORTANT |
|---|
| Make sure all the injectors operate. High resistance in an injector circuit causes the injector to be inoperative without setting a fuel injector DTC. Return to this diagnostic after you complete the Fuel Injector Coil Test. |
DTC P0300 - Engine Misfire Detected
Description
The fuel injector control module (FICM) monitors the compressed natural gas (CNG) fuel tank pressure (FTP) sensor voltage, the fuel tank temperature (FTT) sensor voltage, and the fuel rail temperature (FRT) sensor voltage. The FTP, FTT, and FRT sensor values, and diagnostic data, is communicated to the powertrain control module (PCM) by 2 pulse width modulated (PWM) circuits. This DTC sets when the PCM does not receive any PWM signals from the FICM.
The number below refers to the step number on the diagnostic table.
- 2: This step verifies that the condition is active.
- 3: This step verifies that the ignition voltage circuit to the FICM is OK. If the ignition voltage circuit is open, DTCs P1207, and P1209 may also be set.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | Turn ON the ignition, with the engine OFF. Clear the DTC information with a scan tool. Attempt to start and idle the engine. Observe the DTC information with a scan tool. Does DTC P0611 reset? | Go to Step 3 | Go to Intermittent Conditions |
| 3 | Turn OFF the ignition. Disconnect the harness connector of the fuel injector control module (FICM). Refer to Fuel Injection Control Module Replacement . Turn ON the ignition, with the engine OFF. Probe the ignition feed circuit of the FICM with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 4 | Go to Step 5 |
| 4 | Probe the ground circuits of the FICM with a test lamp connected to B+. Does the test lamp illuminate for all circuits? | Go to Step 7 | Go to Step 6 |
| 5 | Repair the open or short to ground on the ignition feed circuit of the FICM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | |
| 6 | Repair the open on the ground circuit of the FICM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | |
| 7 | Inspect for poor connections at the harness connector of the control module. 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 9 | Go to Step 8 |
| 8 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 9 | |
| 9 | Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 |
| 10 | 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 |
DTC P0611
The numbers below refer to the step numbers on the diagnostic table.
- 3: If DTC P0200 also sets, diagnose P0200 first. A PWM circuit condition between the AF injector relay and the PCM will cause DTCs P0200 and P1020 to set.
- 5: This step determines if the condition is causing an engine misfire. The AF fuel mode relay must be removed in order to prevent a fuel system switch-over.
- 6: This step tests the ignition feed circuit to the AF fuel mode relay. An open ignition feed circuit to the relay will set this DTC.
- 7: This step tests the AF enable circuit to the FICM. An open AF enable circuit between the splice and FICM will set this DTC without an engine misfire.
- 9: This step verifies that the FICM is receiving the PWM input signal from the PCM. The test lamp should blink while the engine is cranking.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Fuel Injection Control Module Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | Turn ON the ignition, with the engine OFF. Clear the DTC information with a scan tool. Start and idle the engine. Observe the DTC information with a scan tool. Does DTC P1020 set? | Go to Step 3 | Go to Step 4 |
| 3 | Is DTC P0200 also set? | Go to DTC P0200 | Go to Step 5 |
| 4 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 5 | Go to Diagnostic Aids |
| 5 | Turn OFF the ignition. IMPORTANT: Removal of the AF fuel mode relay may cause other DTCs to set. Remove the AF fuel mode relay (KL6). Turn ON the ignition, with the engine OFF. Clear the DTCs with a scan tool. Idle the engine at the normal operating temperature. Monitor the misfire current counters with a scan tool. Are any of the misfire current counters incrementing? | Go to Step 9 | Go to Step 6 |
| 6 | Probe the ignition feed circuit of the AF mode relay coil with a test lamp connected to B+. Does the test lamp illuminate? | Go to Step 7 | Go to Step 15 |
| 7 | Turn OFF the ignition. Install the AF fuel mode relay. Disconnect the fuel injector control module (FICM). Refer to Fuel Injection Control Module Replacement . Probe the AF enable circuit with a test lamp connected to a good ground. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? | Go to Step 14 | Go to Step 8 |
| 8 | Turn OFF the ignition. Probe the AF enable circuit with a test lamp connected to B+. Does the test lamp brightly illuminate? | Go to Step 12 | Go to Step 11 |
| 9 | Turn OFF the ignition. Disconnect the FICM. Refer to Fuel Injection Control Module Replacement . Probe the pulse width modulated (PWM) input signal circuit which displays the highest number of misfire current counters with a test lamp connected to B+. Crank the engine. Does the test lamp blink? | Go to Step 14 | Go to Step 10 |
| 10 | Test the PWM input signal circuit for an open or a short to ground between the FICM and the AF injector relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 19 | Go to Step 13 |
| 11 | Test the AF enable circuit for an open between the FICM and the AF fuel mode relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 19 | Go to Step 13 |
| 12 | Test the AF enable circuit for a short to ground between the following: Powertrain control module (PCM) and the splice FICM and the splice AF fuel mode relay and the splice Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 19 | Go to Step 18 |
| 13 | Test for an intermittent and for a poor connection at the AF injector relay. Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 19 | Go to Step 16 |
| 14 | Test for an intermittent and for a poor connection at the FICM. Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 19 | Go to Step 17 |
| 15 | Repair the ignition feed circuit to the AF fuel mode relay coil. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | |
| 16 | Replace the AF injector relay. Did you complete the replacement? | Go to Step 19 | |
| 17 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 19 | |
| 18 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT in Engine Controls. Did you complete the replacement? | Go to Step 19 | |
| 19 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 20 |
| 20 | 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 |
| IMPORTANT |
|---|
| Removal of the AF fuel mode relay may cause other DTCs to set. |
DTC P1020
The numbers below refer to the step numbers on the diagnostic table.
- 2: The engine must Crank or Run on CNG in order for this DTC to test.
- 4: This step verifies that the FICM is able to control the fuel injector. Bi-fuel (KL6) equipped vehicles must be operating on alternative fuel prior to pulsing the CNG fuel injector.
- 5: This step tests if a ground is constantly being applied to the fuel injector.
- 10: A short to ground of the CNG injector B+ circuit will open the inline fuse and cause an entire cylinder bank to set DTCs. Test the CNG injector B+ circuits, bank injector monitor circuit, and the FICM for a shorted condition whenever the inline fuse has opened.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Fuel Injection Control Module Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | Clear the DTC information with a scan tool. Turn OFF the ignition for 30 seconds. Crank and attempt to start the engine. Observe the DTC information with a scan tool. Do any of the DTCs P1021-P1028 fail this ignition? | Go to Step 3 | Go to Diagnostic Aids |
| 3 | Turn OFF the ignition. Disconnect the appropriate compressed natural gas (CNG) fuel injector. Turn ON the ignition, with the engine OFF. Probe the B+ circuit of the CNG fuel injector with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 4 | Go to Step 10 |
| 4 | Probe the control circuit of the CNG fuel injector with a test lamp connected to B+. Turn OFF the ignition for 30 seconds. IMPORTANT: To ensure the fuel mode command is ALT fuel on KL6 equipped vehicles do not crank or start the engine. Turn ON the ignition, with the engine OFF. Perform the fuel injector balance test on the appropriate CNG fuel injector with a scan tool. Refer to Fuel Injector Balance Test with Tech 2 . While observing the test lamp pulse the appropriate CNG fuel injector. Does the test lamp blink while the injector is pulsed? | Go to Step 8 | Go to Step 5 |
| 5 | Does the test lamp remain continuously illuminated? | Go to Step 7 | Go to Step 6 |
| 6 | Test the CNG fuel injector control circuit for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
| 7 | Test the CNG fuel injector 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 13 | Go to Step 12 |
| 8 | Test for an intermittent and for a poor connection at the CNG fuel injector. Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11 |
| 9 | Test for an intermittent and for a poor connection at the fuel injector control module (FICM). Refer to Testing For Intermittent Conditions And Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
| 10 | Repair the open or short to ground on the B+ voltage circuit of the fuel injector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | |
| 11 | Replace the CNG fuel injector. Refer to Fuel Injector Replacement . Did you complete the replacement? | Go to Step 13 | |
| 12 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 13 | |
| 13 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 14 |
| 14 | 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 |
| IMPORTANT |
|---|
| To ensure the fuel mode command is ALT fuel on KL6 equipped vehicles do not crank or start the engine. |
DTC P1021-P1028
The numbers below refer to the step numbers on the diagnostic table.
- 4: This step determines if a CNG related DTC is set.
- 5: This step determines if the condition is present.
- 7: This step determines if the CNG fuel system is the cause of the concern.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Observe the DTC information with a scan tool. Are there any DTCs set? | Go to Step 3 | Go to Step 5 | |
| 3 | With a scan tool, select Captured Info in order to store the powertrain DTC information. Did you complete the action? | Go to Step 4 | ||
| 4 | Turn ON the ignition, with the engine OFF. Observe the DTC information with a scan tool. Does the scan tool display DTC P0005, P0191, P0611, P2146, or P2665? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 5 | |
| 5 | Attempt to start the engine. Does the engine start and idle? | Go to Step 6 | Go to Step 7 | |
| 6 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 7 | Go to Intermittent Conditions | |
| 7 | Turn ON the ignition, with the engine OFF. Observe the fuel rail pressure (FRP) sensor parameter with a scan tool. Does the FRP display remain steady near the specified value? | 310 kPa (45 psi) | Go to ENGINE CRANKS BUT DOES NOT RUN in Engine Controls. | Go to Fuel System Diagnosis |
DTC P1204
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the fuel injector control module (FICM) is powered ON. A loss of power or ground to the FICM may set this DTC. A KL6 vehicle may start on gasoline after several seconds.
- 3: This step determines if the condition is present.
- 5: This step verifies that the PCM is supplying the correct output voltage. The open circuit voltage should be 5 volts.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Clear the DTC information with a scan tool. Turn the ignition OFF for 30 seconds. Attempt to start and idle the engine on compressed natural gas (CNG). Crank the engine for up to 15 seconds if required. Does the engine only operate on gasoline or is DTC P0611 set? | Go to DTC P0611 | Go to Step 3 | |
| 3 | Observe the FICM odd bank circuit status with a scan tool. Does the scan tool display FAULT? | Go to Step 5 | Go to Step 4 | |
| 4 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 5 | Go to Intermittent Conditions | |
| 5 | Turn OFF the ignition. Disconnect the fuel injector control module (FICM) harness connector. Refer to Fuel Injection Control Module Replacement . Turn ON the ignition, with the engine OFF. Measure the voltage from the pulse width modulated (PWM) output circuit with a DMM. Does the DMM display the voltage at the specified value? | 5 V | Go to Step 10 | Go to Step 6 |
| 6 | Is the voltage more than the specified value? | 5.3 V | Go to Step 8 | Go to Step 7 |
| 7 | Test for an open, or a short to ground on the PWM output circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 | |
| 8 | Test for a short to voltage on the PWM output circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11 | |
| 9 | Inspect for proper terminal contact at the harness connector of the powertrain control module (PCM). 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 13 | Go to Step 11 | |
| 10 | Inspect for proper terminal contact at the harness connector of the FICM. 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 13 | Go to Step 12 | |
| 11 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT in Engine Controls. Did you complete the replacement? | Go to Step 13 | ||
| 12 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 13 | ||
| 13 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 14 | |
| 14 | 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 | |
DTC P1207
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the condition is present.
- 5: This step verifies that the PCM is supplying the correct output voltage. The open circuit voltage should be 5 volts.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Observe the FICM diagnostic circuit status with a scan tool. Does the scan tool display FAULT? | Go to Step 3 | Go to Step 4 | |
| 3 | Is DTC P0611 also set? | Go to DTC P0611 | Go to Step 5 | |
| 4 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 5 | Go to Intermittent Conditions | |
| 5 | Turn OFF the ignition. Disconnect the fuel injector control module (FICM) harness connector. Refer to Fuel Injection Control Module Replacement . Turn ON the ignition, with the engine OFF. Measure the voltage from the FICM status circuit with a DMM. Does the DMM display the voltage at the specified value? | 5.0 V | Go to Step 10 | Go to Step 6 |
| 6 | Is the voltage more than the specified value? | 5.3 V | Go to Step 8 | Go to Step 7 |
| 7 | Test for an open, or a short to ground on the FICM status circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 | |
| 8 | Test for a short to voltage on the FICM status circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11 | |
| 9 | Inspect for proper terminal contact at the harness connector of the powertrain control module (PCM). 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 13 | Go to Step 11 | |
| 10 | Inspect for proper terminal contact at the harness connector of the FICM. 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 13 | Go to Step 12 | |
| 11 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT in Engine Controls. Did you complete the replacement? | Go to Step 13 | ||
| 12 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 13 | ||
| 13 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 14 | |
| 14 | 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 | |
DTC P1209
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the condition is present.
- 4: This step determines if the signal circuit of the FTP sensor is the cause of the condition.
- 5: This step determines if the 5-volt reference circuit is the cause of the condition.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the Fuel Tank Pressure (FTP) data parameter with a scan tool. Does the scan tool display the FTP sensor voltage less than the specified value? | 0.1 V | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Intermittent Conditions | |
| 4 | Remove the fuel tank cover. Refer to Fuel Tank Cover Replacement . Disconnect the harness connector of the FTP sensor. Observe the FTP sensor data parameter with a scan tool. Does the scan tool display the FTP sensor voltage more than the specified value? | 4.7 V | Go to Step 5 | Go to Step 6 |
| 5 | Measure the voltage from the 5-volt reference circuit of the FTP sensor with a DMM. Is the voltage less than the specified value? | 4.8 V | Go to Step 7 | Go to Step 8 |
| 6 | Test for a short to ground on the signal circuit of the FTP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 7 | Test for an open or a short to ground on the 5-volt reference circuit of the FTP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 8 | Inspect for proper terminal contact at the harness connector of the FTP 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 12 | Go to Step 10 | |
| 9 | Inspect for proper terminal contact at the harness connector of the fuel injector control module (FICM). 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 12 | Go to Step 11 | |
| 10 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Is the replacement complete? | Go to Step 12 | ||
| 11 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 12 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 | |
| 13 | 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 | |
DTC P1432
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the condition is present.
- 4: This step determines if an open sensor ground circuit condition is present. The FTP and FTT share a sensor ground. An open circuit between the splice and the ground terminal will cause both signal circuits to indicate high voltage.
- 5: This step determines if an open or shorted signal circuit is the cause of the condition.
- 6: This step determines if a shorted 5-volt reference circuit is the cause of the condition.
- 7: This step determines if an open sensor ground circuit between the harness connector of the FTP sensor and the splice is the cause of the condition.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |
| 2 | Turn ON the ignition, with the engine OFF. Observe the Fuel Tank Pressure (FTP) data parameter with a scan tool. Does the scan tool display the FTP sensor voltage more than the specified value? | 4.95 V | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame and/or the Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame and/or the Failure Records data. Does the DTC fail this ignition cycle? | Go to Step 4 | Go to Intermittent Conditions | |
| 4 | Observe the fuel tank temperature (FTT) sensor data parameter with a scan tool. Does the scan tool display the FTT sensor voltage more than the specified value? | 4.5 V | Go to Step 12 | Go to Step 5 |
| 5 | Remove the fuel tank cover. Refer to Fuel Tank Cover Replacement . Disconnect the harness connector of the FTP sensor. Connect a 3-amp fused jumper wire between the signal circuit of the FTP sensor and a known good ground. IMPORTANT: If the jumper fuse opens, repair the signal circuit short to battery voltage. Observe the FTP sensor data parameter with a scan tool. Does the scan tool display the FTP sensor voltage less than the specified value? | 0.25 V | Go to Step 6 | Go to Step 8 |
| 6 | Remove the jumper. Measure the voltage from the 5-volt reference circuit of the FTP sensor with a DMM. Does the DMM display a voltage more than the specified value? | 5.2 V | Go to Step 9 | Go to Step 7 |
| 7 | Probe the ground circuit of the FTP sensor with a test lamp connected to B+. Does the test lamp illuminate? | Go to Step 10 | Go to Step 13 | |
| 8 | Test the signal circuit of the FTP sensor for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 11 | |
| 9 | Test the 5-volt reference circuit of the FTP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 15 | |
| 10 | Inspect for proper terminal contact at the harness connector of the FTP 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 16 | Go to Step 14 | |
| 11 | Inspect for proper terminal contact at the harness connector of the fuel injector control module (FICM). 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 | |
| 12 | Repair the ground circuit of the FTP sensor for an open between the ground terminal and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 16 | ||
| 13 | Repair the ground circuit of the FTP sensor for an open, or high resistance, between the harness connector of the FTP sensor and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 16 | ||
| 14 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | Go to Step 16 | ||
| 15 | Replace the FICM. Refer to Fuel Injection Control Module Replacement . Did you complete the replacement? | Go to Step 16 | ||
| 16 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 17 | |
| 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 | System OK | |
| IMPORTANT |
|---|
| If the jumper fuse opens, repair the signal circuit short to battery voltage. |
DTC P1433
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests if the concern is active.
- 4: This step tests if the concern is active only while operating on gasoline. Disconnecting the high pressure lock-off (HPL) solenoid connector will cause a loss of CNG fuel pressure and force a switchover to gasoline. An HPL DTC will set. Reconnect the HPL connector and clear DTC information after all diagnosis and repairs are complete.
- 5: This step determines if the PCM is receiving 12 volts from the AF fuel mode relay.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | Turn ON the ignition, with the engine OFF. Clear the DTC information with a scan tool. Turn OFF the ignition and wait 30 seconds. Attempt to start and idle the engine. Observe the DTC information with a scan tool. Does DTC P2146 set? | Go to Step 3 | Go to Step 4 |
| 3 | Is DTC P0148 also set? | Go to DTC P0148 | Go to Step 5 |
| 4 | Start and idle the engine on compressed natural gas (CNG). Disconnect the high pressure lock-off (HPL) solenoid connector. Wait for the engine to stall or switchover to gasoline. Attempt to start and idle a stalled engine. Observe the DTC information with a scan tool. Did the DTC fail this ignition? | Go to Step 5 | Go to Intermittent Conditions |
| 5 | Disconnect the powertrain control module (PCM). Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT in Engine Controls. IMPORTANT: Other DTCs will set with the PCM disconnected. Turn ON the ignition, with the engine OFF. IMPORTANT: If the jumper fuse opens, repair the AF enable circuit for a short to voltage condition. Probe the AF Enable Control circuit with a fused jumper that is connected to a good ground. Listen for operation of the AF underhood relays as the circuit is grounded. Do the relays operate when the circuit is grounded? | Go to Step 6 | Go to Step 7 |
| 6 | Turn the ignition OFF. Disconnect the fuel injector control module (FICM) connector. Refer to Fuel Injection Control Module Replacement . Turn ON the ignition, with the engine OFF. Probe the AF Enable Signal circuit at the FICM connector with a fused jumper that is connected to a good ground. Listen for operation of the AF underhood relays as the circuit is grounded. Do the relays operate when the circuit is grounded? | Go to Step 9 | Go to Step 10 |
| 7 | Remove the AF Fuel Mode Relay from the AF Left Relay Block. Probe the ignition feed circuit of the AF mode relay coil with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 8 | Go to Step 11 |
| 8 | Test the AF Enable Control circuit for an open or shorted to ground condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
| 9 | Inspect for poor connections at the harness connector of the PCM. 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 14 | Go to Step 12 |
| 10 | Repair the open in the AF enable circuit between the FICM and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | |
| 11 | Repair the ignition feed circuit to the AF fuel mode relay coil. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | |
| 12 | Replace the PCM. Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT in Engine Controls. Did you complete the replacement? | Go to Step 14 | |
| 13 | Replace the AF Fuel Mode Relay. Did you complete the replacement? | Go to Step 14 | |
| 14 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 15 |
| 15 | 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 |
| IMPORTANT |
|---|
| Other DTCs will set with the PCM disconnected. |
| IMPORTANT |
|---|
| If the jumper fuse opens, repair the AF enable circuit for a short to voltage condition. |
DTC P2146
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if an AF lock-off relay condition is the cause of the concern. You should hear a clicking sound when the high pressure lock-off (HPL) solenoid is commanded ON and OFF.
- 3: This step tests if the concern is active. You should hear a clicking sound when the LPL solenoid is commanded ON and OFF. Repeat the commands as necessary.
- 5: This step tests the ignition voltage circuit to the LPL solenoid.
- 6: This step verifies that the control module is providing ground to the LPL solenoid.
- 7: This step tests if a ground is constantly being applied to the LPL solenoid.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) |
| 2 | Turn ON the ignition, with the engine OFF. Command the high pressure lock-off (HPL) solenoid ON and OFF with a scan tool. Listen for audible operation of the solenoid. Does the HPL solenoid respond to the scan tool commands? | Go to Step 3 | Go to Fuel Lock-Off Relay Diagnosis |
| 3 | Turn ON the ignition, with the engine OFF. Command the low pressure lock-off (LPL) solenoid ON and OFF with a scan tool. Listen for audible operation of the solenoid. Does the LPL solenoid respond to the commanded state? | Go to Step 4 | Go to Step 5 |
| 4 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 5 | Go to Intermittent Conditions |
| 5 | Turn OFF the ignition. Disconnect the LPL solenoid. Refer to Low Pressure Lock-Off (LPL) Solenoid Replacement . Turn ON the ignition, with the engine OFF. Probe the ignition voltage circuit of the LPL solenoid with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 6 | Go to Step 12 |
| 6 | Connect a test lamp between the control circuit of the LPL solenoid and the ignition voltage circuit of the LPL solenoid. Command the LPL solenoid ON and OFF with a scan tool. Does the test lamp turn ON and OFF with each command? | Go to Step 10 | Go to Step 7 |
| 7 | Does the test lamp remain illuminated with each command? | Go to Step 9 | Go to Step 8 |
| 8 | Test the control circuit of the LPL solenoid for an open or for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 |
| 9 | Test the control circuit of the LPL solenoid 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 Step 14 |
| 10 | Inspect for poor connections at the LPL solenoid. 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 |
| 11 | Inspect for poor connections at the harness connector of the control module. 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 |
| 12 | Repair the open or short to ground in the ignition voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 15 | |
| 13 | Replace the LPL solenoid. Refer to Low Pressure Lock-Off (LPL) Solenoid Replacement . Did you complete the replacement? | Go to Step 15 | |
| 14 | Replace the powertrain control module (PCM). Refer to POWERTRAIN CONTROL MODULE (PCM) REPLACEMENT in Engine Controls. Did you complete the replacement? | Go to Step 15 | |
| 15 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 16 |
| 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 |
DTC P2665