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Wiring diagrams Section: Testing & Diagnostics

Engine Controls - 4.3L - Introduction (1 of 2)

Engine Controls - 4.8L, 5.3L, and 6.0L - Introduction (1 of 2)

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Engine Controls - 8.1L - Diagnostics (Dtcs P0172-P0496): Overview GMC Sierra 1500

Testing & Diagnostics ~2121 words

Test Description

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 Heated Oxygen Sensor (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 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

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

4: This step tests for voltage at the fuel injector harness connector. The INJ fuse supplies power to the coil side of the fuel injector harness connector. If the fuse is open, a short to ground on the fuel injector B+ supply circuit is indicated.
5: This step verifies that the PCM is able to control the fuel injector. If the test lamp blinks, then the PCM and wiring are OK.
6: This step tests if a ground is constantly being applied to the fuel injector.

Step	Action	Yes	No
Schematic Reference: 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	Clear the DTCs with a scan tool. Idle the engine at the normal operating temperature. Monitor the misfire current counters with a scan tool. Are any of the misfire current counters incrementing?	Go to Step 4	Go to Step 3
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 as specified in the supporting text or as close to the Freeze Frame/Failure Records that you observed. Does the DTC fail this ignition?	Go to Step 4	Go to Diagnostic Aids
4	Turn OFF the ignition. Disconnect the harness connector of the fuel injector for the cylinder which indicated misfire. Turn ON the ignition, with the engine OFF. Probe the ignition voltage circuit of the fuel injector with a test lamp connected to a good ground. Does the test lamp illuminate?	Go to Step 5	Go to Step 11
5	Connect the J 34730-2C TBI Harness Test Lamp between the control circuit and the ignition 1 voltage circuit of the fuel injector harness connector. See Special Tools . Start the engine. Does the test lamp blink?	Go to Step 9	Go to Step 6
6	Does the test lamp remain illuminated at all times?	Go to Step 8	Go to Step 7
7	Test the control circuit of the fuel injector for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 10
8	Test the control circuit of the fuel injector for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 13
9	Inspect for poor connections at the harness connector of the fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 12
10	Inspect for poor connections at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 13
11	IMPORTANT: The INJ fuses also supply voltage to the ignition coil modules. If a fuse is open, inspect all related circuits for a short to ground. Repair the open or short to ground in the ignition voltage circuit of the fuel injector. Refer to Wiring Repairs in Wiring Systems. Replace the fuse, if necessary. Did you complete the repair?	Go to Step 14
12	Replace the fuel injector. Refer to Fuel Injector Replacement . Did you complete the replacement?	Go to Step 14
13	Replace the PCM. Refer to Control Module References in Computer/Integrating Systems 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. Does the DTC run and pass?	Go to Step 15	Go to Step 2
15	Observe the Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed?	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK

IMPORTANT
The INJ fuses also supply voltage to the ignition coil modules. If a fuse is open, inspect all related circuits for a short to ground.

DTC P0200

The number below refers to the step number on the diagnostic table.

31: When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture Info.

Step	Action	Values	Yes	No
Schematic Reference: 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	Turn OFF the ignition. Remove the air inlet duct from the throttle body. Disconnect the throttle body harness connector. Connect jumper wires between the throttle position (TP) sensor 2 terminals of the throttle body harness connector and the corresponding TP sensor 2 terminals of the throttle body. Turn ON the ignition, with the engine OFF. Close the throttle blade by hand. Observe the TP sensor 2 voltage with a scan tool. Is the TP sensor 2 voltage within the specified range?	0.28-0.81 V	Go to Step 3	Go to Step 7
3	Open the throttle blade to wide open throttle (WOT) by hand. Observe the TP Sensor 2 Voltage parameter on the scan tool. Is the TP Sensor 2 Voltage parameter more than the specified value?	4.60 V	Go to Step 7	Go to Step 4
4	Disconnect the TP sensor harness connector. Disconnect the throttle actuator control (TAC) module harness connector containing the TP sensor circuits. Test the TP sensor low-reference circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 5
5	Turn OFF the ignition for 15 seconds. Connect the TAC module harness connector. Connect the throttle body harness connector. Install the air inlet duct. Turn ON the ignition, with the engine OFF. Select the DTC Info option on the scan tool. Lightly touch and move the related engine wiring harnesses and connectors for the TP sensor while observing the DTC Info. The DTC will set if an intermittent condition is present. Refer to Connector Repairs and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 6
6	Continue to observe DTC Info. Slowly depress the accelerator pedal to WOT, then slowly return the pedal to the released position 3 times. Does the scan tool indicate this DTC failed this ignition?		Go to Step 25	Go to Diagnostic Aids
7	Disconnect the TP sensor harness connector. Measure the voltage at the TP sensor 2 signal circuit with a DMM connected to ground. Is the voltage within the specified range?	3.94-6.06 V	Go to Step 12	Go to Step 8
8	Turn OFF the ignition. Disconnect the TAC module harness connector containing the TP sensor circuits. Turn ON the ignition, with the engine OFF. Test the TP sensor 2 signal circuit for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 9
9	Test the TP sensor 2 signal circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 10
10	Test the TP sensor 2 signal circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 11
11	Disconnect the other TAC module harness connector. Test for a short between the TP sensor 2 signal circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 26
12	Measure the voltage from the TP sensor 2, 5-volt reference circuit to a good ground with a DMM. Refer to Circuit Testing . Is the voltage within the specified range?	4.54-5.21 V	Go to Step 22	Go to Step 13
13	Is the voltage more than the specified value?	5.21 V	Go to Step 14	Go to Step 16
14	Turn OFF the ignition. Disconnect the TAC module harness connector containing the TP sensor circuits. Turn ON the ignition, with the engine OFF. Test the TP sensor 2, 5-volt reference circuit for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 15
15	Turn OFF the ignition. Disconnect the accelerator pedal position (APP) sensor harness connector. Disconnect the other TAC module harness connector. Turn ON the ignition, with the engine OFF. Test the APP sensor 2, 5-volt reference circuit for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 20
16	Disconnect the APP sensor. Is the voltage less than the specified value?	4.54 V	Go to Step 17	Go to Step 28
17	Disconnect the TAC module harness connector containing the TP sensor circuits. Test the TP sensor 2, 5-volt reference circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 18
18	Test the TP sensor 2, 5-volt reference circuit for a short to ground with a DMM. Did you find and correct the condition?		Go to Step 30	Go to Step 19
19	Test the APP sensor 2, 5-volt reference circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 20
20	Test for a short between the TP sensor 2, 5-volt reference circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 21
21	Test for a short between the APP sensor 2, 5-volt reference circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 26
22	Connect a fused jumper between the TP sensor 2 low-reference circuit and the TP sensor 2 signal circuit. Observe the TP Sensor 2 Voltage parameter with a scan tool. Is the TP Sensor 2 parameter near the specified value?	0 V	Go to Step 24	Go to Step 23
23	Turn OFF the ignition. Disconnect the TAC module harness connector containing the TP sensor circuits. Test the TP sensor 2 low-reference circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 30	Go to Step 26
24	Inspect for an intermittent and for a poor connection at the throttle body harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?		Go to Step 30	Go to Step 27
25	Inspect for an intermittent and for a poor connection at the APP sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?		Go to Step 30	Go to Step 28
26	Inspect for an intermittent and for a poor connection at the TAC module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?		Go to Step 30	Go to Step 29
27	Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?		Go to Step 30
28	Replace the APP sensor. Refer to Accelerator Pedal with Position Sensor Replacement . Did you complete the replacement?		Go to Step 30
29	Replace the TAC module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?		Go to Step 30
30	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 31
31	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 P0220

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

2: Listen for a click when the fuel pump relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
4: This step verifies that the PCM is providing voltage to the fuel pump relay.
5: This step tests for an open in the ground circuit to the fuel pump relay.
6: This step tests if voltage is constantly being applied to the control circuit of the fuel pump relay.

Step	Action	Yes	No
Schematic Reference: 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	Turn ON the ignition, with the engine OFF. Command the fuel pump ON and OFF with a scan tool. Does the fuel pump relay turn ON and OFF with each command?	Go to Step 3	Go to Step 4
3	Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition?	Go to Step 4	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
4	Turn OFF the ignition. Disconnect the fuel pump relay. Turn ON the ignition, with the engine OFF. Probe the control circuit of the fuel pump relay with a test lamp connected to a good ground. Command the fuel pump ON and OFF with a scan tool. Does the test lamp turn ON and OFF with each command?	Go to Step 5	Go to Step 6
5	Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the relay. Command the fuel pump 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 11
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 fuel pump relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 10
8	Test the control circuit of the fuel pump relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 10
9	Inspect for poor connections at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 12
10	Inspect for poor connections at the harness connectors of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 14	Go to Step 13
11	Repair the ground circuit of the relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 14
12	Replace the fuel pump relay. Did you complete the replacement?	Go to Step 14
13	Replace the PCM. Refer to Control Module References in Computer/Integrating Systems 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 as specified in the supporting text. Does the DTC run and pass?	Go to Step 15	Go to Step 2
15	Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed?	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK

DTC P0230

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

2: If the actual CKP variation values are not within the learned values, the misfire counters may increment.
3: DTC P0135 or P0155 can be set because of a misfire.

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	Go to Step 5
5	Does the scan tool indicate that the Heated Oxygen Sensor (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	IMPORTANT: An erratic or inconsistent spark is considered a no spark. Turn OFF the ignition. Disconnect the spark plug wire from the spark plug that corresponds to the Misfire Current counters that were incrementing. Refer to Spark Plug Wire Replacement . Install the J 26792 Spark Tester. Start the engine. Does the spark jump the tester gap?		Go to Step 10	Go to Step 9
9	Remove the spark plug wire for the affected cylinders. 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?	700 ohm	Go to Electronic Ignition (EI) System Diagnosis	Go to Step 19
10	Remove the spark plugs from the cylinders that indicated a misfire. Refer to Spark Plug Replacement . Inspect the spark plugs. 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 18	Go to Step 15
12	Is the spark plug oil or coolant fouled?		Go to Symptoms - Engine Mechanical	Go to Step 13
13	Is the spark plug gas fouled?		Go to Step 16	Go to Step 14
14	Did the spark plug show any signs of being cracked, worn, or improperly gapped?		Go to Step 17	Go to Step 15
15	Perform the fuel injector coil test. Refer to Fuel Injector Coil Test . Did you find and correct the condition?		Go to Step 20	Go to Symptoms - Engine Mechanical
16	Perform the fuel system diagnosis. Refer to Fuel System Diagnosis . Did you find and correct the condition?		Go to Step 20	Go to Symptoms - Engine Mechanical
17	Replace or gap the spark plug. Refer to Spark Plug Replacement . Did you complete the action?		Go to Step 20
18	Replace the faulty spark plug. Refer to Spark Plug Replacement . Did you complete the replacement?		Go to Step 20
19	Replace the faulty spark plug wires. Refer to Spark Plug Wire Replacement . Did you complete the replacement?		Go to Step 20
20	Was the customer concern the malfunction indicator lamp (MIL) flashing?		Go to Step 21	Go to Step 22
21	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?	2500 RPM	Go to Step 22	Go to DTC P0420 or P0430
22	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 23
23	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 .

IMPORTANT
An erratic or inconsistent spark is considered a no spark.

DTC P0300

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

2: This step verifies the malfunction is present.
3: This test will isolate the KS from the rest of the circuit.
4: Tapping on the engine block near the appropriate KS will simulate an engine knock.

Step	Action	Values	Yes	No
Schematic Reference: 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	IMPORTANT: If an engine knock can be heard, repair the engine mechanical condition before proceeding with this diagnostic. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the engine within the Conditions for Running the DTC as close to the Freeze Frame/Failure Records data that you observed. Does the scan tool indicate that this diagnostic failed this ignition?		Go to Step 3	Go to Diagnostic Aids
3	Turn the ignition OFF. Disconnect the knock sensor (KS) harness of the appropriate KS. Set the DMM to the 400 K ohm scale. Measure the resistance of the appropriate KS with a DMM connected to battery ground. Is the resistance of the KS within the specified range?	93-107K ohm	Go to Step 4	Go to Step 6
4	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 appropriate KS while observing the signal indicated on the DMM. Is any signal indicated on the DMM while tapping on the engine block near the knock sensor?		Go to Step 5	Go to Step 6
5	Disconnect the powertrain control module (PCM) connector. Refer to Powertrain Control Module (PCM) Replacement . Test the KS signal circuit between the PCM and the KS connector for the following: An open A short to voltage A short to ground Refer to Circuit Testing in Wiring Systems. Did you find and correct the condition?		Go to Step 9	Go to Step 7
6	Replace the KS. Refer to Knock Sensor (KS) 1 Replacement or Knock Sensor (KS) 2 Replacement . Did you complete the replacement?		Go to Step 9
7	Inspect the KS signal circuit for a poor connection at the PCM or the KS harness connector. Refer to Testing for Intermittent Conditions and Poor Connections . If you find a poor connection, repair the connector as necessary. Refer to Connector Repairs . Did you find and correct the condition?		Go to Step 9	Go to Step 8
8	Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?		Go to Step 9
9	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 as specified in the supporting text. Does the DTC run and pass?		Go to Step 10	Go to Step 2
10	With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not 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.

IMPORTANT
Do not tap on plastic engine components.

DTC P0327 or P0332

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

3: This step determines if the fault is present.
6: This step simulates a CKP sensor signal to the PCM. If the PCM receives the signal, the fuel pump will operate for about two seconds.

Step	Action	Values	Yes	No
Schematic Reference: 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	Does the engine start and continue to run?		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	CAUTION: Before proceeding, remove the fuses for the ignition coil and fuel injector feed circuits in order to prevent personal injury from engine rotation, sparks, and excessive engine fueling. IMPORTANT: An internally shorted CAM sensor can cause DTC P0335 to set. Test this circuit for a short before proceeding with this diagnostic table. Refer to Circuit Testing and Wiring Repairs . Turn ON the ignition, with the engine OFF. Disconnect the crankshaft position (CKP) sensor harness connector. Measure the voltage from the CKP sensor 12-volt reference circuit to a good ground with the DMM. Does the DMM display the specified value?	B+	Go to Step 5	Go to Step 7
5	Measure the voltage between the CKP sensor 12-volt reference circuit and the CKP sensor low reference circuit with the DMM. Does the DMM display the specified value?	B+	Go to Step 6	Go to Step 8
6	Momentarily connect the test lamp between the CKP sensor signal circuit and the CKP sensor 12-volt reference circuit. Does the fuel pump operate when voltage was applied to the CKP sensor signal circuit?		Go to Step 11	Go to Step 9
7	Test for an open or a short to ground in the CKP sensor 12-volt reference circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 16	Go to Step 14
8	Test for an open or for high resistance in the CKP sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 16	Go to Step 14
9	Test the CKP sensor signal circuit for the following conditions: High resistance An open A short to ground or low reference A short to voltage or 12-volt reference Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?		Go to Step 16	Go to Step 10
10	Inspect for poor connections at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?		Go to Step 16	Go to Step 14
11	Remove the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Visually inspect the CKP sensor for the following conditions: Excessive play or looseness Excessive air gap between the CKP sensor and the reluctor wheel Physical damage Foreign material passing between the CKP sensor and the reluctor wheel Improper installation Electromagnetic interference in the CKP sensor circuits Refer to Wiring Repairs . Did you find and correct the condition?		Go to Step 16	Go to Step 12
12	Inspect the CKP reluctor wheel for the following conditions: Physical damage Improper installation Excessive endplay or looseness Refer to Crankshaft and Bearings Cleaning and Inspection . Did you find and correct the condition?		Go to Step 16	Go to Step 13
13	Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Did you complete the repair?		Go to Step 16
14	Inspect for poor connections at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you complete the repair?		Go to Step 16	Go to Step 15
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 run and pass?		Go to Step 17	Go to Step 2
17	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?		Go to Diagnostic Trouble Code (DTC) List - Vehicle	System OK

CAUTION
Before proceeding, remove the fuses for the ignition coil and fuel injector feed circuits in order to prevent personal injury from engine rotation, sparks, and excessive engine fueling.

IMPORTANT
An internally shorted CAM sensor can cause DTC P0335 to set. Test this circuit for a short before proceeding with this diagnostic table. Refer to Circuit Testing and Wiring Repairs .

DTC P0335

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	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 sensor (CKP) circuits for the following conditions: Wiring routed too closely to secondary ignition wires or components Wiring routed too closely to after market add-on electrical equipment Wiring routed to closely to solenoids, relays, and motors Electromagnetic interference in the CKP sensor circuits Did you find and correct the condition?	Go to Step 12	Go to Step 4
4	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 12	Go to Step 5
5	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 12	Go to Step 6
6	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 12	Go to Step 7
7	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 12	Go to Step 8
8	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 12	Go to Step 9
9	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 12	Go to Step 10
10	Inspect the reluctor wheel for the following conditions: Physical damage Improper installation Excessive endplay or looseness Refer to Crankshaft and Bearings Installation . Did you find and correct the condition?	Go to Step 12	Go to Step 11
11	Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . 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. 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

IMPORTANT
If DTC P0335 is also set, diagnose DTC P0335 before proceeding with this DTC.

DTC P0336

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

3: This step inspects for electromagnetic interference (EMI) on the CMP sensor circuits.
6: Damage to the face of the sensor could indicate foreign material passing between the CMP sensor and the reluctor wheel. This condition would cause this DTC to set. Damage to the reluctor wheel would affect the CMP sensor output.

Step	Action	Yes	No
Schematic Reference: 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	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 Diagnostic Aids
3	Visually and physically inspect all circuits going to the camshaft position (CMP) sensor for the following: Being routed too close to secondary ignition wires or components Being routed too close to after market add-on electrical equipment Being routed too close to solenoids, relays, and motors If you find incorrect routing, correct the harness routing Did you find and correct the condition?	Go to Step 9	Go to Step 4
4	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 9	Go to Step 5
5	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 9	Go to Step 6
6	Remove the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Visually inspect the CMP sensor for the following conditions: Physical damage Excessive wear of the sensor Loose or improper installation Did you find and correct the condition?	Go to Step 9	Go to Step 7
7	Visually inspect the CMP sensor reluctor ring for damage. If the CMP reluctor ring is damaged, refer to Crankshaft and Bearings Cleaning and Inspection . Did you find and correct the condition?	Go to Step 9	Go to Step 8
8	Replace the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Did you complete the replacement?	Go to Step 9
9	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 10
10	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	Go to Diagnostic Trouble Code (DTC) List - Vehicle	System OK

DTC P0341

The number below refers to the step number on the diagnostic table.

5: 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	Yes	No
Schematic Reference: 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	Start the engine. Observe the Camshaft Position (CMP) Sensor High to Low and Low to High Transition parameter with a scan tool. Does the scan tool 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 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 6
5	Start the engine. Observe the CMP Sensor High to Low and Low to High Transition parameters with the 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 8	Go to Step 7
6	Test the 12-volt reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 14	Go to Step 9
7	Test the CMP sensor signal circuit for an open or 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 9
8	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 14	Go to Step 10
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 Connector Repairs . Did you find and correct the condition?	Go to Step 14	Go to Step 13
10	Remove the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Visually inspect the CMP sensor for the following conditions: Physical damage Loose or improper installation Wiring routed too close to the secondary ignition components Did you find and correct the condition?	Go to Step 14	Go to Step 11
11	Visually inspect the CMP sensor reluctor ring for damage. If the CMP reluctor ring is damaged, refer to Crankshaft and Bearings Cleaning and Inspection . Did you find and correct the condition?	Go to Step 14	Go to Step 12
12	Replace the CMP sensor. Refer to Camshaft Position (CMP) 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

DTC P0342

The number below refers to the step number on the diagnostic table.

5: 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: 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	Start the engine. Observe the Camshaft Position (CMP) Sensor High to Low and Low to High Transition parameter with a scan tool. Does the scan tool 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 CMP sensor. Turn ON the ignition, with the engine OFF. Probe the signal 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 7	Go to Step 5
5	Start the engine. Observe the CMP Sensor High to Low and Low to High Transition parameters with the 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 6	Go to Step 10
6	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?	0.2 V	Go to Step 8	Go to Step 9
7	Test the CMP sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 15	Go to Step 10
8	Test the low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?		Go to Step 15	Go to Step 10
9	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 15	Go to Step 11
10	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 15	Go to Step 14
11	Remove the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Visually inspect the CMP sensor for the following conditions: Physical damage Loose or improper installation Wiring routed too close to the secondary ignition components Did you find and correct the condition?		Go to Step 15	Go to Step 12
12	Visually inspect the CMP sensor reluctor ring for damage. If the CMP reluctor ring is damaged, refer to Crankshaft and Bearings Cleaning and Inspection . Did you find and correct the condition?		Go to Step 15	Go to Step 13
13	Replace the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Did you complete the replacement?		Go to Step 15
14	Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?		Go to Step 15
15	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 16
16	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?		Go to Diagnostic Trouble Code (DTC) List - Vehicle	System OK

DTC P0343

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

3: This step verifies the integrity of the IC circuit and the PCM output.
4: This step tests for a short to ground on the IC circuit.

Step	Action	Values	Yes	No
Schematic Reference: 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	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 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	Turn OFF the engine. Disconnect the respective ignition coil. Start the engine. Measure the frequency at the ignition control (IC) circuit with the DMM set to DC Hertz. Refer to Measuring Frequency . Is the frequency within the specified range?	3-20 Hz	Go to Step 7	Go to Step 4
4	Measure the voltage from the IC circuit of the ignition coil to a good ground with the DMM. Is the voltage more than the specified value?	1 V	Go to Step 13	Go to Step 5
5	Turn OFF the ignition. Disconnect the powertrain control module (PCM) connector. Test the IC circuit between the ignition coil connector and the PCM connector for continuity with the DMM. Does the DMM indicate continuity?		Go to Step 6	Go to Step 14
6	Test the respective IC circuit for a short to ground. Refer to Testing for Short to Ground . Did you find and correct the condition?		Go to Step 17	Go to Step 10
7	Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the ignition coil with a test lamp that is connected to battery ground. Refer to Troubleshooting with a Test Lamp . Does the test lamp illuminate?		Go to Step 8	Go to Step 11
8	Probe the ground circuit of the ignition coil with a test lamp connected to battery voltage. Refer to Troubleshooting with a Test Lamp . Does the test lamp illuminate?		Go to Step 9	Go to Step 12
9	Test for an intermittent and for a poor connection at the ignition coil. 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
10	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 16
11	Repair the open in the ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?		Go to Step 17
12	Repair the open in the ground circuit for the ignition coil. Refer to Wiring Repairs . Did you complete the repair?		Go to Step 17
13	Repair the IC circuit for a short to voltage. Refer to Wiring Repairs . Did you complete the repair?		Go to Step 17
14	Repair open in the IC circuit. Refer to Wiring Repairs . Did you complete the repair?		Go to Step 17
15	Replace the ignition coil. Refer to Ignition Coil(s) 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-P0358

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

5: A catalytic converter which has been discolored may be due to an engine running rich, lean or had a previous misfire. Verifying the fuel trim percentages may be of assistance in determining if such a condition exists.
6: This steps inspects for conditions than 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 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 HO2S 2 voltage parameter on the scan tool for the applicable bank. Is the applicable 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 heated oxygen sensor (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 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 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 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 key is turned OFF and the correct conditions are met.

Heat is transferred into a vehicle fuel tank while the vehicle is operating. When the vehicle is turned OFF, a change in the fuel tank vapor temperature occurs, which results in corresponding pressure changes in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure 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 (0.020 in) test orifice on the bottom-front of the J 41413-200 Evaporative Emissions System Tester (EEST). Activate the J 41413-200 with the remote switch. Align the red flag on the flow meter with the floating indicator. De-activate the J 41413-200 with the remote switch. Install the J 41415-40 Fuel Tank Cap Adapter or GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . Turn ON the ignition, with the engine OFF. Command the evaporative emissions (EVAP) canister vent solenoid valve closed with a scan tool. Introduce nitrogen and fill the EVAP system until the floating stabilizes with the remote switch. 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. Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 . 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. 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. Remove the J 41413-VLV once smoke is observed. 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. 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. Install the fuel fill cap to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT . 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 0.50 mm (0.020 in) test orifice on the bottom-front of the J 41413-200 . Use the remote switch to activate the J 41413-200 . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . 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's 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. Have any more DTCs not been diagnosed?	Go to Diagnostic Trouble Code (DTC) List - Vehicle	Go to Step 7
7	IMPORTANT: The malfunction indicator lamp (MIL) may remain ON after the repair unless the DTCs are cleared. Clear the DTCs with the scan tool.Did you complete the action?	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.

IMPORTANT
The malfunction indicator lamp (MIL) may remain ON after the repair unless the DTCs are cleared.

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
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 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 canister 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 batter 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 canister vent solenoid valve and battery positive voltage circuit of the EVAP canister vent solenoid valve at the EVAP canister vent solenoid 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 (Pickup) Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement (Cab/Chassis) . 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

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 (Pickup) or Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement (Cab/Chassis) . A pinched EVAP hose A damaged EVAP canister - Refer to Evaporative Emission (EVAP) Canister Replacement (Pickup) or Evaporative Emission (EVAP) Canister Replacement (Cab/Chassis) . 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. Install the J 41415-40 Fuel Tank Cap Adapter or the GE-41415-50 Fuel Cap Adapter to the fuel fill pipe. Connect the J 41413-200 NITROGEN/SMOKE supply hose to the J 41415-40 or the GE-41415-50 to the fuel fill pipe. Turn the ignition ON, with the engine OFF. Turn the NITROGEN/SMOKE valve on the J 41413-200 to NITROGEN. 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 FTP parameter in H2O to the J 41413-200 VACUUM/PRESSURE gage. 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?	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?	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 FTP parameter on the scan tool. 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?	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. 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 . 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 . 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 (Pickup) Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement (Cab/Chassis) . Did you complete the action?		Go to Step 17
12	Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement (Pickup) or Evaporative Emission (EVAP) Canister Replacement (Cab/Chassis) . 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 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. 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.

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 parameter 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. Is the fuel tank pressure sensor parameter greater than the specified value?	4.8 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 (Pickup) or Fuel Tank Replacement (Cab/Chassis - Front) or Fuel Tank Replacement (Cab/Chassis - Rear) . 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 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 powertrain control module (PCM). 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. Have any other DTCs 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 (FTP) 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 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 (Pickup) or Fuel Tank Replacement (Cab/Chassis - Front) or Fuel Tank Replacement (Cab/Chassis - Rear) . 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 powertrain control module (PCM). 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 canister 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 numbers below refer to the step numbers on the diagnostic table.

4: 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.
6: This step verifies proper operation of the FTP sensor.
7: 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
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	Turn OFF the ignition. Connect the J 41413-200 Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.5 mm (0.020 in) test orifice on the bottom-front of the J 41413-200 . Use the remote switch to activate the J 41413-200 . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . Install the J 41415-40 Fuel Tank Cap Adapter or the GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. Install the fuel fill cap to the J 41415-40 or the GE-41415-50 . Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or the GE-41415-50 . 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. Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 . 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. 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. Remove the J 41413-VLV once smoke is observed. 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. 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. Install the fuel fill cap to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT . 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. Connect the J 41413-200 nitrogen/smoke supply hose and vehicle fuel fill cap to the J 41415-40 or GE-41415-50 . 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. 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. Use the J 41413-200 to pressurize the EVAP system to the first specified value. Is the fuel tank pressure sensor parameter more than the second specified value?	13 in H2O 5 in H2O	Go to Step 8	Go to Step 14
8	Stop introducing nitrogen into the EVAP system with the remote switch. 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 . 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 purge solenoid valve to 30 percent. Observe the vacuum/pressure gage on the J 41413-200 and the FTP parameter on the scan tool. Use the purge/seal function to seal the system, with a scan tool. Is the difference between the FTP parameter on a scan tool and the vacuum/pressure gage on the J 41413-200 within the specified value, until the vacuum reached the abort limit on the scan tool?	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 purge pipe from the EVAP canister 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 an open or high resistance. Refer to Circuit Testing and Wiring Repairs . 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. Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Engine/Chassis (Pickup) or Evaporative Emission (EVAP) Hoses/Pipes Replacement - Engine/Chassis (Cab/Chassis) . Did you complete the repair?		Go to Step 21
20	Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement (Pickup) or Evaporative Emission (EVAP) Canister Replacement (Cab/Chassis) . Did you complete the replacement?		Go to Step 21
21	IMPORTANT: DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results. Connect the J 41413-200 to the fuel fill pipe. Turn the nitrogen/smoke valve to NITROGEN. Seal the EVAP system using the EVAP Purge/Seal function with a scan tool. Pressurize the EVAP system to the specified value. Observe the J 41413-200 pressure/vacuum gage for 5 minutes. Does the J 41413-200 pressure/vacuum gage remain constant?	5 in H2O	Go to Step 22	Go to Step 3
22	Observe the fuel tank pressure sensor parameter with a scan tool. Is the scan tool fuel tank pressure parameter within the specified value of the J 41413-200 pressure/vacuum gage?	1 in H2O	Go to Step 23	Go to Step 6
23	Observe the J 41413-200 pressure/vacuum gage. Increase the EVAP canister 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
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
DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.

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

Engine Controls - 8.1L - Diagnostics (Dtcs P0172-P0496): Overview GMC Sierra 1500

Test Description

System Description

More articles — Engine Controls - 8.1L - Diagnostics (Dtcs P0172-P0496)

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