Test Description
The number below refers to the step number on the diagnostic table.
- 2: If the voltage is varying above and below the specified value, the condition is not present.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Start the engine. Allow the engine to reach operating temperature. Refer to Scan Tool Data List . Operate the engine at 1,500 RPM for 30 seconds. While observing the affected Heated Oxygen Sensor (HO2S) Voltage parameter with a scan tool, quickly cycle the throttle from closed throttle to wide open throttle, 3 times. Did the HO2S Voltage parameter change more than the specified value? | 200 mV | 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. 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 4 | Go to Testing for Intermittent Conditions and Poor Connections | |
| 4 | Turn OFF the ignition. Disconnect the affected HO2S. Turn ON the ignition, with the engine OFF. Observe the HO2S Voltage parameter with a scan tool. Is the HO2S Voltage parameter more than the specified value? | 800 mV | Go to Step 6 | Go to Step 5 |
| 5 | Measure the voltage from the high signal circuit of the HO2S harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing . Is the voltage more than the specified value? | 0.2 V | Go to Step 7 | Go to Step 8 |
| 6 | IMPORTANT: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S high signal circuit for a short to voltage. Refer to the following: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 7 | Measure the voltage from the low signal circuit of the HO2S harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing . Is the voltage more than the specified value? | 2 V | Go to Step 11 | Go to Step 9 |
| 8 | Test the HO2S high signal circuit for an open or high resistance. Refer to the following: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 9 | Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S harness connector on the engine harness side and the low signal circuit of the HO2S harness connector on the engine harness side. Observe the HO2S Voltage parameter with a scan tool. Is the HO2S Voltage parameter less than the specified value? | 100 mV | Go to Step 12 | Go to Step 10 |
| 10 | Test the HO2S low signal circuit for an open or high resistance. Refer to the following: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 11 | Test the HO2S low signal circuit for a short to voltage. Refer to the following: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 12 | Test for shorted terminals and for poor connections at the HO2S. Refer to the following: Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition? | Go to Step 16 | Go to Step 14 | |
| 13 | Test for shorted terminals and for poor connections at the powertrain control module (PCM). Refer to the following: Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition? | Go to Step 16 | Go to Step 15 | |
| 14 | Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 . Did you complete the replacement? | Go to Step 16 | ||
| 15 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 16 | ||
| 16 | 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 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 - Vehicle | System OK | |
| IMPORTANT |
|---|
| The sensor may be damaged if the circuit is shorted to a voltage source. |
DTC P0140 or P0160
The number below refers to the step number on the diagnostic table.
- 7: An EVAP canister that is saturated will cause a rich condition.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Are any DTCs other than DTC P0172 or P0175 also set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 3 | |
| 3 | Install a 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? | 13% | Go to Step 4 | Go to Diagnostic Aids |
| 4 | 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 5 | Go to Step 6 |
| 5 | Turn OFF the engine. Visually and physically inspect the following items: The evaporative emission (EVAP) lines and components for damage or blockage-Refer to Evaporative Emissions (EVAP) Hose Routing Diagram . The inlet screen of the mass air flow (MAF) sensor for blockage The vacuum hoses for splits, kinks, and proper connections-Refer to Emission Hose Routing Diagram . The air intake duct for being collapsed or restricted The air filter for being dirty or restricted For objects blocking the throttle body Did you find and correct the condition? | Go to Step 8 | Go to Step 7 | |
| 6 | 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 the following: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition? | Go to Step 8 | Go to Fuel System Diagnosis | |
| 7 | Inspect for the following: Excessive fuel in the crankcase Proper operation of the fuel pressure regulator-Refer to Fuel System Diagnosis . All injectors are functioning properly-Refer to Fuel Injector Coil Test . Did you find and correct the condition? | Go to Step 8 | Go to Symptoms - Engine Mechanical | |
| 8 | IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function to reset the Long Term Fuel Trim. Turn ON the ignition, with the engine OFF. 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 9 | |
| 9 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK |
| IMPORTANT |
|---|
| After repairs, use the scan tool Fuel Trim Reset function to reset the Long Term Fuel Trim. |
DTC P0172 or P0175
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 individual misfire events. A misfire rate that is high enough can cause the 3-way catalytic converter (TWC) to overheat under certain driving conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for TWC overheating are present. If the PCM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set.
The number below refers to the step number on the diagnostic table.
- 2: If the actual CKP variation values are not within the learned values, the misfire counters may increment.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | IMPORTANT: You must perform the crankshaft position (CKP) system variation learn procedure before proceeding with this diagnostic table. Refer to CKP System Variation Learn Procedure . Start the engine. Allow the engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records. Monitor all of the Misfire Counters with the scan tool. Are any of the Misfire Current counters incrementing? | Go to Step 3 | Go to Diagnostic Aids | |
| 3 | Are any other DTCs set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 4 | |
| 4 | Can any abnormal engine noise be heard? | Go to Symptoms - Engine Mechanical in Engine Mechanical | Go to Step 5 | |
| 5 | Does the scan tool indicate that the HO2S bank 1 sensor 1 or HO2S bank 2 sensor 1 voltage parameters are below the specified value? | 200 mV | Go to DTC P0131 or P0151 | Go to Step 6 |
| 6 | Does the scan tool indicate that the HO2S bank 1 sensor 1 or HO2S bank 2 sensor 1 voltage parameters are fixed above the specified value? | 900 mV | Go to DTC P0132 or P0152 | Go to Step 7 |
| 7 | Inspect the following components: The vacuum hoses and seals for splits, restrictions, and improper connections-Refer to Emission Hose Routing Diagram . The throttle body and intake manifold for vacuum leaks The crankcase ventilation system for vacuum leaks-Refer to Crankcase Ventilation System Inspection/Diagnosis in Engine Mechanical. The powertrain control module (PCM) grounds for corrosion and loose connections-Refer to Ground Distribution Schematics in Wiring Systems. The exhaust system for restrictions-Refer to Restricted Exhaust in Engine Exhaust. The fuel for contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool) . Did you find and correct the condition? | Go to Step 20 | Go to Step 8 | |
| 8 | Turn OFF the ignition. Disconnect the spark plug wire from the spark plug that corresponds to the Misfire Current counter that was incrementing. Refer to Spark Plug Wire Replacement . Install the J 26792 Spark Tester to a good ground. See Special Tools . Start the engine. Does the spark jump the tester gap, and is the spark consistent? | Go to Step 10 | Go to Step 9 | |
| 9 | Remove the spark plug wire for the affected cylinder. Refer to Spark Plug Wire Replacement . Inspect the spark plug wire. Refer to Spark Plug Wire Inspection . Measure the resistance of the spark plug wire with a DMM. Is the spark plug wire resistance less than the specified value? | 1,000 ohm per 30 cm (per ft) | Go to Step 15 | Go to Step 20 |
| 10 | Remove the spark plug from the cylinder that indicated a misfire. Inspect the spark plug. Refer to Spark Plug Inspection . Does the spark plug appear to be OK? | Go to Step 11 | Go to Step 12 | |
| 11 | Exchange the suspected spark plug with another cylinder that is operating properly. Refer to Spark Plug Replacement . Operate the vehicle under the same conditions that the misfire occurred. Did the misfire move with the spark plug? | Go to Step 19 | Go to Step 16 | |
| 12 | Are the spark plugs oil or coolant fouled? | Go to Symptoms - Engine Mechanical in Engine Mechanical | Go to Step 13 | |
| 13 | Are the spark plugs gas fouled? | Go to Step 17 | Go to Step 14 | |
| 14 | Do the spark plugs show any signs of being cracked, worn, or improperly gapped? | Go to Step 18 | Go to Step 16 | |
| 15 | Inspect the distributor cap and repair or replace as necessary. Refer to Distributor Inspection . Did you complete the action? | Go to Step 21 | ||
| 16 | Perform the fuel injector coil test. Refer to Fuel Injector Coil Test . Did you find and correct the condition? | Go to Step 21 | Go to Symptoms - Engine Mechanical in Engine Mechanical | |
| 17 | Perform the fuel system diagnosis. Refer to Fuel System Diagnosis . Did you find and correct the condition? | Go to Step 21 | Go to Symptoms - Engine Mechanical in Engine Mechanical | |
| 18 | Replace or gap the spark plug. Refer to Spark Plug Replacement . Did you complete the replacement? | Go to Step 21 | ||
| 19 | Replace the faulty spark plug. Refer to Spark Plug Replacement . Did you complete the replacement? | Go to Step 21 | ||
| 20 | Replace the faulty spark plug wire. Refer to Spark Plug Wire Replacement . Did you complete the replacement? | Go to Step 21 | ||
| 21 | Was the customer concern the malfunction indicator lamp (MIL) flashing? | Go to Step 22 | Go to Step 23 | |
| 22 | 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 . Does the DTC run and pass? | 2,500 RPM | Go to Step 23 | Go to DTC P0420 or P0430 |
| 23 | 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 24 | |
| 24 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
| IMPORTANT |
|---|
| You must perform the crankshaft position (CKP) system variation learn procedure before proceeding with this diagnostic table. Refer to CKP System Variation Learn Procedure . |
DTC P0300
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step ensures the malfunction is present.
- 3: This step tests the KS for proper operation.
- 6: If the KS signal wire is shorted to ground or is shorted to voltage, the KS may still produce a signal.
- 7: If the KS low reference is shorted to ground or is shorted to voltage, the KS may still produce a signal.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | IMPORTANT: If an engine knock can be heard, repair the engine mechanical condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical . 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. Does the DTC fail this ignition? | Go to Step 3 | Go to Diagnostic Aids |
| 3 | Turn OFF the ignition. Disconnect the powertrain control module (PCM). Connect a DMM between the knock sensor (KS) signal circuit and the KS low reference circuit at the PCM connector. Set the DMM to the 400 mV AC hertz scale. Refer to Measuring Frequency . IMPORTANT: Do not tap on plastic engine components. Tap on the engine block near the KS while observing the signal indicated on the DMM. Does the DMM display a fluctuating frequency while tapping on the engine block? | Go to Step 6 | Go to Step 4 |
| 4 | Disconnect the KS. Test the KS signal circuit and the KS low reference circuit for an open or a high resistance. Refer to Testing for Continuity . Did you find and correct the condition? | Go to Step 12 | Go to Step 5 |
| 5 | Test the KS signal circuit for a short to the KS low reference circuit. Refer to Testing for Short to Ground and Testing for a Short to Voltage . Did you find and correct the condition? | Go to Step 12 | Go to Step 8 |
| 6 | Test the KS signal circuit for a short to ground and for a short to voltage. Refer to Testing for Short to Ground and Testing for a Short to Voltage . Did you find and correct the condition? | Go to Step 12 | Go to Step 7 |
| 7 | Test the KS low reference circuit for a short to ground and for a short to voltage. Refer to Testing for Short to Ground and Testing for a Short to Voltage . 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 KS. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
| 10 | Replace the KS. Refer to Knock Sensor (KS) Replacement . Did you complete the replacement? | Go to Step 12 | |
| 11 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | |
| 12 | 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. Does 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 - Vehicle | System OK |
| IMPORTANT |
|---|
| If an engine knock can be heard, repair the engine mechanical condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical . |
| IMPORTANT |
|---|
| Do not tap on plastic engine components. |
DTC P0327
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step verifies that the malfunction is present.
- 3: This step tests for electromagnetic interference (EMI) on the CKP sensor circuits.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views and Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | IMPORTANT: If DTC P0335 is also set, diagnose DTC P0335 before proceeding with this DTC. 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 3 | Go to Testing for Intermittent Conditions and Poor Connections | |
| 3 | Inspect all of the crankshaft position (CKP) sensor circuits for the following conditions: Wiring routed too closely to secondary ignition wires or components Wiring routed too closely to aftermarket add-on electrical equipment Wiring routed to closely to solenoids, relays, and motors Electromagnetic interference (EMI) in the CKP sensor circuits Did you find and correct the condition? | Go to Step 14 | Go to Step 4 | |
| 4 | Disconnect the CKP sensor connector. Refer to Crankshaft Position (CKP) Sensor Replacement . Measure the voltage from the 12-volt reference circuit of the CKP sensor with a DMM. Is the voltage within the specified value? | B+ | Go to Step 5 | Go to Step 13 |
| 5 | Test the 12-volt reference circuit for an intermittent condition or shorted to other circuits. Refer to Testing for Electrical Intermittents and Inducing Intermittent Fault Conditions . Did you find and correct the condition? | Go to Step 14 | Go to Step 6 | |
| 6 | Test the low reference circuit for an intermittent condition. Refer to Testing for Electrical Intermittents and Inducing Intermittent Fault Conditions . Did you find and correct the condition? | Go to Step 14 | Go to Step 7 | |
| 7 | Test the CKP sensor signal circuit for an intermittent condition. Refer to Testing for Electrical Intermittents and Inducing Intermittent Fault Conditions . Did you find and correct the condition? | Go to Step 14 | Go to Step 8 | |
| 8 | Test for an intermittent and for a poor connection at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 9 | |
| 9 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 10 | |
| 10 | Remove the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Inspect the CKP sensor for the following conditions: Physical damage Improper installation Excessive play or looseness Excessive air gap between the CKP sensor and the reluctor wheel Foreign material passing between the CKP sensor and the reluctor wheel Insufficient fuel Did you find and correct the condition? | Go to Step 14 | Go to Step 11 | |
| 11 | Inspect the reluctor wheel for the following conditions: Physical damage Improper installation Excessive endplay or looseness Refer to Crankshaft Position (CKP) Reluctor Ring Replacement . Did you find and correct the condition? | Go to Step 14 | Go to Step 12 | |
| 12 | Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Did you complete the replacement? | Go to Step 14 | ||
| 13 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 14 | ||
| 14 | 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 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 - Vehicle | System OK | |
| IMPORTANT |
|---|
| If DTC P0335 is also set, diagnose DTC P0335 before proceeding with this DTC. |
DTC P0336
The number below refers to the step number on the diagnostic table.
- 6: This step tests the CMP sensor signal circuit. Applying a voltage causes the CMP sensor high to low and low to high parameter to increase if the circuit and the PCM are operating properly.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Connect a scan tool. Start the engine. Observe the CMP sensor high to low and low to high transition parameter with a scan tool. Does the CMP sensor high to low and low to high parameter increment? | 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. 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 4 | Go to Diagnostic Aids | |
| 4 | Turn OFF the ignition. Disconnect the camshaft position (CMP) sensor. Turn ON the ignition, with the engine OFF. Probe the 12-volt reference circuit of the CMP sensor with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors . Does the test lamp illuminate? | Go to Step 5 | Go to Step 8 | |
| 5 | Turn OFF the ignition. Jumper the CMP circuits from the CMP sensor to the CMP sensor harness connector. Refer to Using Connector Test Adapters . Turn ON the ignition, with the engine OFF. Measure the voltage drop from the low reference circuit of the CMP sensor to a good ground with a DMM. Refer to Circuit Testing . Is the voltage more than the specified value? | 0.20 V | Go to Step 9 | Go to Step 6 |
| 6 | Turn OFF the ignition. Disconnect the CMP sensor. Start the engine. Observe the CMP sensor high to low and low to high transition parameters with a scan tool. Momentarily and repeatedly probe the signal circuit of the CMP sensor with a test lamp that is connected to battery voltage. Does the CMP sensor high to low and low to high transition counters increment when the test lamp contacts the signal circuit? | Go to Step 12 | Go to Step 7 | |
| 7 | Did the test lamp illuminate when the signal circuit was touched? | Go to Step 10 | Go to Step 11 | |
| 8 | Test the 12-volt reference circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 9 | Test the low reference circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 10 | Test the CMP sensor signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 11 | Test the CMP sensor signal circuit for an open or for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 13 | |
| 12 | Test for an intermittent and for a poor connection at the CMP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 14 | |
| 13 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 15 | |
| 14 | Replace the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Did you complete the replacement? | Go to Step 16 | ||
| 15 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 16 | ||
| 16 | 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 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 - Vehicle | System OK | |
DTC P0341
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step determines if the DTC is an intermittent.
- 3: This step verifies if the IC timing signal from the PCM is available at the ignition control module.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Clear the DTCs with a scan tool. Disconnect the injector harness connector. Crank the engine for 15 seconds. Does DTC P0351 set? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections | |
| 3 | Turn OFF the ignition. Connect the injector harness connector. Disconnect the ignition control module (ICM). Probe the ignition control (IC) timing control circuit of the ICM harness connector with a DMM that is connected to a good ground. Crank the engine. Observe the AC voltage on the DMM. Does the voltage measure within the specified range? | 1-4 V | Go to Step 4 | Go to Step 6 |
| 4 | Turn OFF the ignition. Probe the ground circuit of the ICM harness connector with a test lamp connected to battery voltage. Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 | |
| 5 | Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the ICM harness connector with a test lamp connected to a good ground. Does the test lamp illuminate? | Go to Step 10 | Go to Step 14 | |
| 6 | Turn OFF the ignition. Disconnect the powertrain control module (PCM). Probe the IC timing control circuit of the PCM harness connector with a test lamp connected to battery voltage. Does the test lamp illuminate? | Go to Step 12 | Go to Step 7 | |
| 7 | Test for an open in the IC timing control circuit between the PCM and the ICM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 8 | |
| 8 | Connect the PCM. Turn ON the ignition, with the engine OFF. Probe the IC timing control circuit at the ICM harness connector with a DMM set to the DC scale and connected to a good ground. Does the voltage measure more than the specified value? | 1 V | Go to Step 13 | Go to Step 9 |
| 9 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections or Connector Repairs . Does you find and correct the condition? | Go to Step 17 | Go to Step 16 | |
| 10 | Test for an intermittent and for a poor connection at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 15 | |
| 11 | Repair the open in the ground circuit. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 17 | ||
| 12 | Repair the short to ground in the IC timing control circuit. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 17 | ||
| 13 | Repair the short to voltage in the IC timing control circuit. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 17 | ||
| 14 | Repair the open in the ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 17 | ||
| 15 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | Go to Step 17 | ||
| 16 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 17 | ||
| 17 | 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 18 | |
| 18 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK | |
DTC P0351
The numbers below refer to the step numbers on the diagnostic table.
- 5: This step indicates that a catalytic converter which has been discolored may be due to an engine running rich, lean, or had a previous severe misfire. Verifying the fuel trim percentages may be of assistance in determining if such a condition exists.
- 6: This step inspects for conditions that can cause the TWC efficiency to appear degraded.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Review the DTC information on the scan tool. Are any other DTCs set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 3 | |
| 3 | IMPORTANT: A new converter with less than 161 kilometers (100 miles) on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition. Start and idle the engine. Allow the engine to reach operating temperature. Increase the engine speed to 2,000 RPM for 2 minutes. Ensure Closed Loop operation is enabled. Return the engine to a stabilized idle. Observe the catalyst monitor Heated Oxygen Sensor (HO2S) 2 Voltage parameter on the scan tool for the applicable bank. Is the HO2S 2 Voltage parameter transitioning below the first specified value and above the second specified value? | 350 mV 600 mV | Go to Step 5 | Go to Step 4 |
| 4 | Clear the DTCs with a scan tool. 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 DTC P0420 or P0430 set? | Go to Step 5 | Go to Diagnostic Aids | |
| 5 | IMPORTANT: Verify that the three-way catalytic converter (TWC) is a high quality part that meets the original equipment manufacturer (OEM) specifications. Visually and physically inspect the TWC for the following conditions: Physical damage Severe discoloration caused by excessive temperatures. Internal rattles caused by loose catalyst substrate Restrictions-Refer to Restricted Exhaust . Did you find and correct the condition? | Go to Step 10 | Go to Step 6 | |
| 6 | Visually inspect the exhaust system for the following conditions: Leaks-Refer to Exhaust Leakage . Physical damage Loose or missing hardware The HO2S 2 for the applicable bank for proper torque Did you find and correct the condition? | Go to Step 10 | Go to Step 7 | |
| 7 | Visually inspect the HO2S 2 at the applicable bank for the following conditions: The pigtail and wiring harness contacting the exhaust or any ground Road damage Did you find a condition? | Go to Step 8 | Go to Step 9 | |
| 8 | Replace the applicable HO2S 2 sensor. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 . Did you complete the replacement? | Go to Step 10 | ||
| 9 | NOTE: In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter. Replace the TWC. Refer to Catalytic Converter Replacement (4.3L, 4.8L, and 5.3L Engines) or Catalytic Converter Replacement (6.0L and 8.1L Engines) or Catalytic Converter Replacement (6.6L Engine) .Did you complete the replacement? | Go to Step 10 | ||
| 10 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. CAUTION: Refer to Road Test Caution . IMPORTANT: A new converter with less than 161 kilometers (100 miles) on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition. 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 11 | |
| 11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK |
| IMPORTANT |
|---|
| A new converter with less than 161 kilometers (100 miles) on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition. |
| IMPORTANT |
|---|
| Verify that the three-way catalytic converter (TWC) is a high quality part that meets the original equipment manufacturer (OEM) specifications. |
| NOTE |
|---|
| In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter. |
| CAUTION |
|---|
| Refer to Road Test Caution . |
| IMPORTANT |
|---|
| A new converter with less than 161 kilometers (100 miles) on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition. |
DTC P0420 or P0430
This diagnostic tests the evaporative emission (EVAP) system for a small leak when the ignition is turned OFF, and the correct conditions are met.
Heat from the exhaust system is transferred into a vehicle fuel tank while the vehicle is operating. When the ignition is turned OFF, a change in the fuel tank vapor temperature occurs. With the EVAP system sealed, this results in corresponding pressure changes in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure (FTP) sensor input. The control module then makes a judgement on the integrity of the system. With a 0.51 mm (0.020 in) leak in the system, the amount of pressure change observed is significantly less than that of a sealed system.
If the control module detects a pressure change less than a calibrated amount, DTC P0442 sets.
The numbers below refer to the step numbers on the diagnostic table.
- 3: Introducing smoke in 15-second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
- 5: This step verifies that repairs are complete and that no other condition is present.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.20 in) test orifice on the bottom-front of the J 41413-200 Evaporative Emissions System Tester (EEST). See Special Tools . Use the remote switch to activate the J 41413-200 . See Special Tools . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . See Special Tools . Install the J 41415-40 Fuel Tank Cap Adapter or the GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister vent solenoid valve closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter stable floating indicator position to the red flag. Is the floating indicator below the red flag? | Go to Diagnostic Aids | Go to Step 3 |
| 3 | IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. Turn OFF the ignition. Connect the J 41413-200 power supply clips to a known good 12-volt source. See Special Tools . Install the J 41415-40 to the fuel fill pipe. See Special Tools . Connect the J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE. See Special Tools . Use the remote switch to introduce smoke into the EVAP system. Use the J 41413-VLV EVAP Service Port Vent Fitting to open the EVAP service port. See Special Tools . Remove the J 41413-VLV once smoke is observed. See Special Tools . Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT High Intensity White Light. See Special Tools . Continue to introduce smoke at 15-second intervals until the leak source has been located. Did you locate and repair a leak source? | Go to Step 5 | Go to Step 4 |
| 4 | Disconnect the J 41415-40 or GE-41415-50 from the fuel fill pipe. See Special Tools . Install the fuel fill cap to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port. See Special Tools . Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT . See Special Tools . Continue to introduce smoke at 15-second intervals until the leak source has been located. Did you locate and repair a leak source? | Go to Step 5 | Go to Diagnostic Aids |
| 5 | IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.20 in) test orifice on the bottom-front of the J 41413-200 . See Special Tools . Use the remote switch to activate the J 41413-200 . See Special Tools . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . See Special Tools . Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter stable floating indicator position to the red flag. Is the floating indicator below the red flag? | Go to Step 6 | Go to Step 2 |
| 6 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK |
| IMPORTANT |
|---|
| Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. |
| IMPORTANT |
|---|
| Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. |
| IMPORTANT |
|---|
| Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. |
DTC P0442
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests if the concern is active. The EVAP canister purge solenoid valve is PWM. You should hear a clicking sound when the EVAP canister purge solenoid valve is commanded to 50 percent. The clicking sound should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased.
- 5: This step verifies that the control module is providing ground to the EVAP canister purge solenoid valve.
- 6: This step tests if a ground is constantly being applied to the EVAP canister purge solenoid valve.
| Step | Action | Yes | No |
|---|---|---|---|
| Connector End Views Reference: Engine Controls Connector End Views and Powertrain Control Module (PCM) Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister purge solenoid valve to 50 percent, then to 0 percent with a scan tool. Does the EVAP canister purge solenoid valve respond to the commanded state? | 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 Testing for Intermittent Conditions and Poor Connections |
| 4 | Turn OFF the ignition. Disconnect the EVAP canister purge solenoid valve harness connector. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the EVAP canister purge solenoid valve with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 |
| 5 | Connect a test lamp between the control circuit of the EVAP canister purge solenoid valve and the ignition 1 voltage circuit of the EVAP canister purge solenoid valve. Command the EVAP canister purge solenoid valve to 0 percent with a scan tool. Does the test lamp illuminate? | Go to Step 8 | Go to Step 6 |
| 6 | Command the EVAP canister purge solenoid valve to 50 percent with a scan tool. Does the test lamp illuminate or pulse when the EVAP purge solenoid valve is commanded to 50 percent? | Go to Step 9 | Go to Step 7 |
| 7 | Test the control circuit of the EVAP canister purge solenoid valve for an open or for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
| 8 | Test the control circuit of the EVAP canister purge solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs . 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 EVAP canister purge solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
| 10 | Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
| 11 | Repair the open or short to ground in the ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 14 | |
| 12 | Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | Go to Step 14 | |
| 13 | Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup, and programming. 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 - Vehicle | System OK |
DTC P0443
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.
| Control Module Command | EVAP Canister Purge Solenoid Valve | EVAP Canister Vent Solenoid Valve |
|---|---|---|
| ON | Open | Closed |
| OFF | Closed | Open |
DTC P0446
The numbers below refer to the step numbers on the diagnostic table.
- 2: Listen for a click when the valve operates. Verify that both the ON and the OFF states are commanded.
- 5: This step verifies that the control module is providing ground to the EVAP canister vent solenoid valve.
- 6: This step tests if the EVAP canister vent solenoid valve control circuit is grounded.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister vent solenoid valve ON and OFF with the scan tool. Do you hear or feel a click from the EVAP canister vent solenoid valve when the valve is commanded ON and OFF? | 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 Testing for Intermittent Conditions and Poor Connections |
| 4 | Turn OFF the ignition. Disconnect the EVAP canister vent solenoid valve. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the EVAP canister vent solenoid valve with a test lamp connected to a good ground. Refer to Troubleshooting with a Test Lamp . Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 |
| 5 | Connect a test lamp between the control circuit of the EVAP vent solenoid and battery positive voltage circuit of the EVAP canister vent solenoid valve at the EVAP vent valve harness connector. Command the EVAP canister vent solenoid valve ON and OFF with a scan tool. Does the test lamp turn ON and OFF with each command? | Go to Step 9 | 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 EVAP canister vent solenoid valve for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
| 8 | Test the control circuit of the EVAP canister vent solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
| 9 | Inspect for poor connections at the harness connector of the EVAP canister vent solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
| 10 | Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
| 11 | IMPORTANT: If the fuse is open, inspect all related circuits for a short to ground. Repair the open or short to ground in the battery positive voltage circuit. Refer to Wiring Repairs .Did you complete the repair? | Go to Step 14 | |
| 12 | Replace the EVAP canister vent solenoid valve. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement . Did you complete the replacement? | Go to Step 14 | |
| 13 | Replace the control module. Refer to Control Module References for replacement, setup, and programming. 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 - Vehicle | System OK |
| IMPORTANT |
|---|
| If the fuse is open, inspect all related circuits for a short to ground. |
DTC P0449
The fuel tank pressure (FTP) sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal voltage varies, depending on EVAP system pressure or vacuum. The controller uses this FTP signal to determine atmospheric pressure for use in the engine-off small leak test, P0442. Before using this signal as an atmospheric reference, it must first be re-zeroed. If the FTP signal is out of range during the re-zero procedure, this DTC will set.
The numbers below refer to the step numbers on the diagnostic table.
- 4: This step tests for the signal voltage that represents atmospheric pressure. Removing the fuel fill cap ensures a vented EVAP system. Record the value for possible use later in the diagnostic table.
- 5: This step tests the accuracy of the FTP sensor by comparing the electrical signal value to the EEST mechanical gage value.
- 8: A restricted EVAP system will not allow the nitrogen to flow freely through the system. A restriction will cause the FTP signal voltage parameter to decrease as the pressure builds.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram and Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Is DTC P0446, P0452, P0453, or P0651 also set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 3 | |
| 3 | Inspect the evaporative emission (EVAP) system for the following conditions: A damaged EVAP canister vent solenoid valve-Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement . A pinched EVAP hose A damaged EVAP canister-Refer to Evaporative Emission (EVAP) Canister Replacement . Did you find and correct the condition? | Go to Step 17 | Go to Step 4 | |
| 4 | Remove the fuel fill cap. Turn ON the ignition, with the engine OFF. Observe and record the fuel tank pressure (FTP) parameter in volts with a scan tool. Is the fuel tank pressure sensor parameter within the specified amount? | 1.3-1.7 V | Go to Step 5 | Go to Step 14 |
| 5 | IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature. Turn OFF the ignition. Install the fuel fill cap. Connect the J 41413-200 Evaporative Emission System Tester (EEST) power supply clips to a known good 12-volt source. See Special Tools . Install the J 41415-40 Fuel Tank Cap Adapter or the GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools . Connect the J 41413-200 NITROGEN/SMOKE supply hose to the J 41415-40 or the GE-41415-50 to the fuel fill pipe. See Special Tools . Turn the ignition ON, with the engine OFF. Turn the NITROGEN/SMOKE valve on the J 41413-200 to NITROGEN. See Special Tools . Using a scan tool PURGE/SEAL function, seal the EVAP system. Observe the fuel tank pressure sensor in H2O using a scan tool. Use a remote switch to pressurize the EVAP system to the first specified value. Allow at least 30 seconds for pressure in the EVAP system to stabilize. Compare the fuel tank pressure (FTP) parameter in H2O to the J 41413-200 VACUUM/PRESSURE gage. See Special Tools . Is the difference between the FTP parameter on a scan tool and the VACUUM/PRESSURE gage on the J 41413-200 within the second specified value? See Special Tools . | 5 in H2O 1 in H2O | Go to Step 6 | Go to Step 14 |
| 6 | Release the pressure on the EVAP system with the scan tool. Is the difference between the FTP parameter on the scan tool and the VACUUM/PRESSURE gage on the J 41413-200 within the specified value? See Special Tools . | 1 in H2O | Go to Step 7 | Go to Step 14 |
| 7 | Start the engine. Allow the engine to idle. IMPORTANT: Using more than 20 percent purge can cause a misdiagnosis. Use the PURGE/SEAL function of a scan tool to command 20 percent purge. Observe the VACUUM/PRESSURE gage on the J 41413-200 and the fuel tank pressure parameter on the scan tool. See Special Tools . Allow the vacuum to increase to the first specified value. Is the difference between the FTP parameter on the scan tool and the VACUUM/PRESSURE gage on the J 41413-200 within the second specified value? See Special Tools . | 5 in H2O 1 in H2O | Go to Step 8 | Go to Step 14 |
| 8 | Turn ON the ignition, with the engine OFF. Turn the NITROGEN/SMOKE valve on the J 41413-200 to NITROGEN. See Special Tools . Observe the FTP sensor in volts using a scan tool. Pressurize the EVAP system with the remote switch. Allow enough time for pressure to stabilize. Is the difference between the observed FTP sensor voltage and the voltage recorded in Step 4 more than the specified value? | 0.2 V | Go to Step 9 | System OK |
| 9 | Disconnect the EVAP vent hose from the EVAP canister vent solenoid valve with pressure still applied from the J 41413-200 . See Special Tools . Refer to Evaporative Emissions (EVAP) Hose Routing Diagram . Observe the FTP sensor in volts using a scan tool. Is the difference between the observed FTP sensor voltage and the voltage recorded in Step 4 more than the specified value? | 0.2 V | Go to Step 10 | Go to Step 11 |
| 10 | Disconnect the EVAP vapor pipe from the EVAP canister with pressure still applied from the J 41413-200 . See Special Tools . Refer to Evaporative Emissions (EVAP) Hose Routing Diagram . Observe the FTP sensor in volts using a scan tool. Is the difference between the observed FTP sensor voltage and the voltage recorded in Step 4 more than the specified value? | 0.2 V | Go to Step 13 | Go to Step 12 |
| 11 | Repair or replace the EVAP canister vent solenoid. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement . Did you complete the action? | Go to Step 17 | ||
| 12 | Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement . Did you complete the replacement? | Go to Step 17 | ||
| 13 | Repair or replace the pinched or restricted EVAP vapor pipe. Refer to Evaporative Emissions (EVAP) Hose Routing Diagram . Did you complete the action? | Go to Step 17 | ||
| 14 | Test for an intermittent and for a poor connection at the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 15 | |
| 15 | Test the low reference circuit of the FTP sensor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 16 | |
| 16 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | Go to Step 17 | ||
| 17 | Reconnect all components and release any pressure or vacuum applied to the EVAP system. Turn ON the ignition, with the engine OFF. Observe and record the fuel tank pressure (FTP) parameter in H2O with a scan tool. Is the fuel tank pressure sensor parameter within the specified amount? | 1 to +1 in H2O | Go to Step 18 | Go to Step 2 |
| 18 | Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid closed with a scan tool. Turn the NITROGEN/SMOKE valve on the J 41413-200 to NITROGEN. See Special Tools . Pressurize the EVAP system to the first specified value with the remote switch. Observe the fuel pressure sensor in H2O using a scan tool. Command the EVAP canister vent solenoid valve open with a scan tool. Is the fuel tank pressure sensor parameter less than the second specified value? | 5 in H2O 1 in H2O | Go to Step 19 | Go to Diagnostic Aids |
| 19 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 20 | |
| 20 | IMPORTANT: The malfunction indicator lamp (MIL) may remain ON after the repair unless the DTCs are cleared. Clear the DTCs with a scan tool.Did you complete the action? | System OK | ||
| IMPORTANT |
|---|
| Ensure that the vehicle underbody temperature is similar to the ambient temperature. |
| IMPORTANT |
|---|
| Using more than 20 percent purge can cause a misdiagnosis. |
| IMPORTANT |
|---|
| The malfunction indicator lamp (MIL) may remain ON after the repair unless the DTCs are cleared. |
DTC P0451
The numbers below refer to the step numbers on the diagnostic table.
- 5: This step tests for the proper operation of the circuit in the high voltage range.
- 6: The 5-volt reference circuit for the FTP is routed through connector C152. This area may provide a good test point for diagnosing concerns with this circuit.
- 7: The FTP sensor signal circuit is routed through connector C152. This area may provide a good test point for diagnosing concerns with this circuit.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Idle the engine for 1 minute. Monitor the diagnostic trouble code (DTC) information with a scan tool. Did DTC P0641 or P0651 fail this ignition? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 3 | |
| 3 | Observe the fuel tank pressure sensor voltage with the scan tool. Does the scan tool indicate that fuel tank pressure sensor parameter is less than the specified value? | 0.1 V | Go to Step 5 | Go to Step 4 |
| 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 Testing for Intermittent Conditions and Poor Connections | |
| 5 | Turn OFF the ignition. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle . Disconnect the fuel tank wiring harness at the fuel tank harness connector. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the fuel tank pressure (FTP) sensor and the signal circuit of the FTP sensor. Turn ON the ignition, with the engine OFF. Observe the fuel tank pressure sensor voltage with a scan tool. Does the scan tool indicate that the fuel tank pressure sensor parameter is near the specified value? | 5 V | Go to Step 8 | Go to Step 6 |
| 6 | Test the 5-volt reference circuit of the FTP sensor for an open between the fuel tank harness connector and the control module. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 7 | |
| 7 | Test the signal circuit of the FTP sensor for a short to ground or an open between the fuel tank harness connector and the control module. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 8 | Remove the fuel tank. Refer to Fuel Tank Replacement . Inspect the fuel tank wiring harness for the following conditions: Damaged wiring Poor connections Broken wires inside the insulation-Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | |
| 9 | Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 . Did you complete the replacement? | Go to Step 12 | ||
| 11 | Replace the control module. Refer to Control Module References for replacement, setup, and programming. 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 - Vehicle | System OK | |
DTC P0452
The number below refers to the step number on the diagnostic table.
- 2: If DTC P0641 or P0651 is set, the 5-volt reference circuit may be shorted to a voltage.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Idle the engine for 1 minute. Monitor the diagnostic trouble code (DTC) information with the scan tool. Did DTC P0641 or P0651 fail this ignition? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 3 | |
| 3 | Turn ON the ignition, with the engine OFF. Observe the fuel tank pressure sensor voltage with a scan tool. Is the fuel tank pressure sensor parameter more than the specified value? | 4.3 V | Go to Step 5 | Go to Step 4 |
| 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 Testing for Intermittent Conditions and Poor Connections | |
| 5 | Turn OFF the ignition. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle . Disconnect the fuel tank wiring harness at the fuel tank harness connector. Turn ON the ignition, with the engine OFF. Observe the fuel tank pressure sensor voltage with a scan tool. Does the scan tool indicate that the fuel tank pressure sensor parameter is more than the specified value? | 1 V | Go to Step 6 | Go to Step 7 |
| 6 | Test the signal circuit of the fuel tank pressure (FTP) for a short to voltage between the fuel tank harness connector and the control module. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12 | |
| 7 | Probe the low reference circuit of the FTP sensor at the fuel tank harness connector with a test lamp connected to battery voltage. Refer to Circuit Testing . Did the test lamp illuminate? | Go to Step 9 | Go to Step 8 | |
| 8 | Test the low reference circuit of the FTP sensor for an open between the fuel tank harness connector and the control module. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 10 | |
| 9 | Remove the fuel tank. Refer to Fuel Tank Replacement . Disconnect the FTP sensor harness connector. Inspect the fuel tank wiring harness for the following: Damaged wiring Poor connections Broken wires inside the insulation-Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 11 | |
| 10 | Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12 | |
| 11 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | Go to Step 13 | ||
| 12 | Replace the control module. Refer to Control Module References for replacement, setup, and programming. 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 - Vehicle | System OK | |
DTC P0453
The fuel tank pressure (FTP) sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal voltage varies depending on EVAP system pressure or vacuum. The controller uses this FTP signal to determine atmospheric pressure for use in the engine OFF small leak test, P0442. This DTC will set if the control module detects an intermittent signal from the FTP that would prevent the engine-off small leak test, P0442, from running.
The number below refers to the step number on the diagnostic table.
- 3: Sealing the system will allow normal pressure in the EVAP system to preload the sensor. This will help put the sensor in a range that is more sensitive, making the test more accurate.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram and Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Are DTCs P0442, P0446, P0452, P0453, or P0651 also set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 |
| 3 | Inspect for an intermittent and for a poor connection at the fuel tank pressure (FTP) sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | Go to Step 5 | Go to Step 4 |
| 4 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | Go to Step 5 | |
| 5 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
DTC P0454
The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent solenoid valves.
| Control Module Command | EVAP Canister Purge Solenoid Valve | EVAP Canister Vent Solenoid Valve |
|---|---|---|
| ON | Open | Closed |
| OFF | Closed | Open |
DTC P0455
The number below refers to the step number on the diagnostic table.
- 6: A normal operating FTP sensor should increase above 5 inches of H2O and stop between 6-7 inches of H2O.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram and Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Inspect the evaporative emission (EVAP) system for the following conditions: Loose, missing, or damaged service port Schrader valve Loose, incorrect, missing, or damaged fuel fill cap A damaged EVAP canister purge solenoid valve Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle . Inspect the EVAP system for the following conditions: Disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses A damaged EVAP canister vent solenoid valve or EVAP canister Did you find and correct the condition? | Go to Step 21 | Go to Step 3 | |
| 3 | IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn OFF the ignition. Connect the J 41413-200 Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source. See Special Tools . Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.20 in) test orifice on the bottom-front of the J 41413-200 . See Special Tools . Use the remote switch to activate the J 41413-200 . See Special Tools . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . See Special Tools . Install the J 41415-40 Fuel Tank Cap Adapter or GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools . Install the fuel fill cap to the J 41415-40 or GE-41415-50 . See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes. Compare the flow meter stable floating indicator position to the red flag. Is the floating indicator below the red flag? | Go to Step 6 | Go to Step 4 | |
| 4 | IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. Turn OFF the ignition. Connect the J 41413-200 power supply clips to a known good 12-volt source. See Special Tools . Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Connect the J 41413-200 to the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE. See Special Tools . Use the remote switch to introduce smoke into the EVAP system. Use the J 41413-VLV EVAP Service Port Vent Fitting to open the EVAP service port. See Special Tools . Remove the J 41413-VLV once smoke is observed. See Special Tools . Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT High Intensity White Light. See Special Tools . Continue to introduce smoke at 15-second intervals until the leak source has been located Did you locate and repair a leak source? | Go to Step 21 | Go to Step 5 | |
| 5 | Disconnect the J 41415-40 or GE-41415-50 from the fuel fill pipe. See Special Tools . Install the fuel fill cap to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port. See Special Tools . Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT . See Special Tools . Continue to introduce smoke at 15-second intervals until the leak source has been located. Did you locate and repair a leak source? | Go to Step 21 | Go to Step 6 | |
| 6 | Use the remote switch to stop introducing smoke. Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Connect the J 41413-200 nitrogen/smoke supply hose and vehicle fuel fill cap to the J 41415-40 or GE-41415-50 . See Special Tools . Command the EVAP canister vent solenoid valve open with a scan tool. Compare the fuel tank pressure sensor parameter with a scan tool to the J 41413-200 pressure/vacuum gage. See Special Tools . Is the difference between the 2 gages less than the specified value? | 1 in H2O | Go to Step 7 | Go to Step 14 |
| 7 | Seal the EVAP system using the EVAP Purge/Seal function with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to NITROGEN. See Special Tools . Use the J 41413-200 to pressurize the EVAP system to the first specified value. See Special Tools . Is the fuel tank pressure sensor parameter more than the second specified value? | 10 in H2O 5 in H2O | Go to Step 8 | Go to Step 14 |
| 8 | Use the remote switch to stop introducing nitrogen into the EVAP system. Increase the EVAP canister purge solenoid valve to 100 percent. Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Step 9 | Go to Step 11 |
| 9 | Connect the nitrogen/smoke hose to the EVAP service port. Remove the J 41415-40 or GE-41415-50 . See Special Tools . Install the fuel fill cap to the fuel fill pipe. Start the engine. Allow the engine to idle. Use the purge/seal function to seal the system, with a scan tool. Command the EVAP canister purge solenoid valve to 30 percent. Observe the vacuum/pressure gage on the J 41413-200 and the FTP parameter on the scan tool. See Special Tools . Allow the vacuum to increase on the gage of the J 41413-200 , until it reaches approximately 16 inch H2O. See Special Tools . Use the purge/seal function to seal the system, with a scan tool. Is the difference between the FTP parameter on the scan tool and the vacuum/pressure gage on the J 41413-200 within the specified value until the vacuum reached the abort limit on a scan tool? See Special Tools . | 1 in H2O | Go to Step 10 | Go to Step 14 |
| 10 | Did the FTP parameter on a scan tool display more than the specified value? | 3.2 V | Go to Diagnostic Aids | Go to Step 17 |
| 11 | Disconnect the EVAP canister purge pipe from the EVAP purge solenoid valve. Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Step 18 | Go to Step 12 |
| 12 | Disconnect the EVAP purge pipe at the EVAP canister. Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Step 19 | Go to Step 13 |
| 13 | Disconnect the EVAP vapor pipe at the EVAP canister. Is the fuel tank pressure sensor parameter less than the specified value? | 1 in H2O | Go to Step 20 | Go to Step 16 |
| 14 | Test for an intermittent and for a poor connection at the fuel tank pressure (FTP) sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 21 | Go to Step 15 | |
| 15 | Test the low reference circuit of the FTP sensor for and open or for high resistance. Did you find and correct the condition? | Go to Step 21 | Go to Step 17 | |
| 16 | Repair the pinched or obstructed EVAP vapor pipe. Did you complete the repair? | Go to Step 21 | ||
| 17 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | Go to Step 21 | ||
| 18 | Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | Go to Step 21 | ||
| 19 | Repair the restriction in the EVAP purge pipe. Did you complete the repair? | Go to Step 21 | ||
| 20 | Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement . Did you complete the replacement? | Go to Step 21 | ||
| 21 | IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.20 in) test orifice on the bottom-front of the J 41413-200 . See Special Tools . Use the remote switch to activate the J 41413-200 . See Special Tools . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . See Special Tools . Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. See Special Tools . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . See Special Tools . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter stable floating indicator position to the red flag. Is the floating indicator below the red flag? | 5 in H2O | Go to Step 22 | Go to Step 4 |
| 22 | Compare the FTP sensor parameter with a scan tool to the J 41413-200 pressure/vacuum gage. See Special Tools . Is the difference between the 2 gages less than the specified value? | 1 in H2O | Go to Step 23 | Go to Step 6 |
| 23 | Observe the J 41413-200 pressure/vacuum gage. See Special Tools . Increase the EVAP purge solenoid valve to 100 percent. Does the pressure decrease? | Go to Step 24 | Go to Step 11 | |
| 24 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK | |
| IMPORTANT |
|---|
| Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. |
| IMPORTANT |
|---|
| Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. |
| IMPORTANT |
|---|
| Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. |
DTC P0455
This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.
| Control Module Command | EVAP Canister Purge Solenoid Valve | EVAP Canister Vent Solenoid Valve |
|---|---|---|
| ON | Open | Closed |
| OFF | Closed | Open |
DTC P0496
The numbers below refer to the step numbers on the diagnostic table.
- 5: This test will determine the ability of the PCM and the IAC valve control circuits to control the IAC valve.
- 7: This test will determine the ability of the PCM to provide the IAC valve control circuits with a ground. On a normal operating system, the test lamp should not flash while the IAC Counts are incrementing.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 | IMPORTANT: Ensure that the Engine Speed parameter stabilizes with each Commanded RPM change to determine if the engine speed stays within 100 RPM of the Commanded RPM. Set the parking brake and block the drive wheels. Start the engine. Turn OFF all accessories. Slowly increment engine speed to 1,700 RPM, then to 600 RPM, then to 1,700 RPM with the scan tool RPM control function. Exit the RPM Control function. Did the Engine Speed parameter stabilize within 100 RPM of the commanded RPM? | 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. 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 4 | Go to Diagnostic Aids |
| 4 | Turn OFF the ignition. Disconnect the idle air control (IAC) valve. Connect the J 37027-1A IAC Motor Driver to the IAC valve. See Special Tools . Start the engine. Command the IAC valve in until 600 RPM is reached with the J 37027-1A . See Special Tools . Command the IAC valve out until 1,700 RPM is reached with the J 37027-1A . See Special Tools . Return the engine speed to the Desired Idle Speed parameter. Did the Engine Speed parameter steadily decrease to 600 RPM and steadily increase to 1,700 RPM when the IAC valve was commanded in and out? | Go to Step 5 | Go to Step 11 |
| 5 | Connect a test lamp between one of the IAC valve control circuits and a good ground. Start the engine. Observe the IAC Counts parameter with a scan tool. Command high RPM with the J 37027-1A until the IAC Counts parameter starts to increment. See Special Tools . Command low RPM with the J 37027-1A until the IAC Counts parameter starts to increment. See Special Tools . Return the Engine Speed parameter to the Desired Idle Speed parameter. Repeat the above procedure for the other 3 IAC valve control circuits. Did the test lamp remain ON, never flashing, while the IAC Counts were incrementing for any of the IAC valve control circuits? | Go to Step 10 | Go to Step 6 |
| 6 | Did the test lamp remain OFF, never flashing, while the IAC Counts were incrementing for any of the IAC valve control circuits? | Go to Step 9 | Go to Step 7 |
| 7 | Connect a test lamp between the IAC coil A low circuit and the IAC coil A high circuit. Observe the IAC Counts parameter with a scan tool and observe the test lamp. Command high RPM with the J 37027-1A until the IAC Counts parameter starts to increment. See Special Tools . Command low RPM with the J 37027-1A until the IAC Counts parameter starts to increment. See Special Tools . Return the Engine Speed parameter to the Desired Idle Speed parameter. Repeat the above procedure with the test lamp connected between the IAC coil B low control circuit and the IAC coil B high control circuit. Did the test lamp stay illuminated and never flashing while the IAC Counts were incrementing for any of the IAC valve control circuits? | Go to Step 8 | Go to Step 16 |
| 8 | Test for an intermittent and for a poor connection at the IAC valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 12 |
| 9 | Turn OFF the ignition. Disconnect the powertrain control module (PCM). Test the circuit where the test lamp remained OFF for the following conditions: An open circuit A short to ground A short to another IAC valve control circuit-Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 12 |
| 10 | Turn ON the ignition. Test the IAC valve control circuit where the test lamp remained ON for the following conditions: A short to voltage A short to another IAC valve control circuit-Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 12 |
| 11 | Inspect for the following conditions: Throttle body damage and tampering Throttle lever screw tampering, if equipped Restricted air intake system-Inspect for a possible collapsed/clogged air intake duct, before and after the air filter element, restricted air filter element, restriction at the throttle body intake screen, if equipped. Remove the IAC valve. Refer to Idle Air Control (IAC) Valve Replacement . Inspect for the following conditions: A clogged IAC passage Excessive deposits on the throttle plate Excessive deposits in the throttle bore Excessive deposits on IAC valve pintle Did you find and correct the condition? | Go to Step 17 | Go to Step 14 |
| 12 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 13 |
| 13 | Disconnect the PCM. Test all IAC valve control circuits for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 16 |
| 14 | Test for an intermittent and for a poor connection at the IAC valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 17 | Go to Step 15 |
| 15 | Replace the IAC valve. Refer to Idle Air Control (IAC) Valve Replacement . Did you complete the replacement? | Go to Step 17 | |
| 16 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 17 | |
| 17 | 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 18 |
| 18 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK |
| IMPORTANT |
|---|
| Ensure that the Engine Speed parameter stabilizes with each Commanded RPM change to determine if the engine speed stays within 100 RPM of the Commanded RPM. |
DTC P0506
See also:
• Scan Tool Data List