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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 234 (ENGINE CONTROLS - SELF-DIAGNOSTICS)DIAGNOSTIC TESTSDTC P0410: SECONDARY AIR INJECTION SYSTEMDIAGNOSTIC PROCEDURES

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8

Diagnostic Procedures

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Cadillac Seville and 2003 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM.
Did DTC P0412 or DTC P0418 also set? If yes, see DTC P0412: SECONDARY AIR INJECTION RELAY CONTROL CIRCUIT or DTC P0418: SECONDARY AIR INJECTION PUMP RELAY CONTROL CIRCUIT . If no, go to next step.
Test the AIR pump fuse. Is the fuse open? If yes, go to step 23. If no, go to next step.
Turn ignition on, with engine off. Command the AIR system on and off with a scan tool. Does the AIR pump turn on and off when commanded with a scan tool? If yes, go to step 12. If no, go to next step.

NOTE: Before probing you must identify the correct relay terminals. For circuit reference, see WIRING DIAGRAMS .

Turn ignition off. Remove the AIR pump relay. Probe the battery positive circuit of the AIR pump relay with a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 29.
Turn ignition on. Probe the AIR pump relay control circuit with a test light connected to a good ground. Does the test light illuminate? If yes, go to step 24. If no, go to next step.
Connect the Heavy Duty Fused Jumper between the AIR pump relay battery positive circuit and the AIR pump relay supply voltage circuit at the AIR pump relay connector. Does the AIR pump turn on? If yes, go to step 34. If no, go to next step.
Remove the Heavy Duty Fused Jumper from the AIR pump relay connector. Disconnect the AIR pump harness connector. Reconnect the Heavy Duty Fused Jumper at the relay connector. Probe the supply voltage circuit at the AIR pump connector with a test light connected to good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 30.
Remove the Heavy Duty Fused Jumper from the AIR pump relay connector. Connect a test light between the AIR pump supply voltage circuit and the AIR pump ground circuit at the AIR pump harness connector. Reconnect the Heavy Duty Fused Jumper at the AIR pump relay connector. Does the test light illuminate? If yes, go to next step. If no, go to step 31.
Remove the Heavy Duty Fused Jumper. Remove the test light from the AIR pump connector. Connect a Heavy Duty Fused Jumper between each of the terminals in the AIR pump harness connector and the corresponding terminals on the AIR pump. Reconnect the Heavy Duty Fused Jumper at the AIR pump relay connector. Measure the voltage between the AIR pump supply voltage circuit at the AIR pump relay and the AIR pump supply voltage circuit at the AIR pump. Is the voltage more than 0.5 volts? If yes, go to step 30. If no, go to next step.
Measure the voltage between the AIR pump ground circuit at the AIR pump harness connector to a good ground. Is the voltage more than 0.5 volts? If yes, go to step 31. If no, go to step 33.
Start and idle the engine. Allow the engine to reach Closed Loop operation. Command the AIR system on with a scan tool while observing the PRE-CATALYST HO2S VOLTAGE parameters. Does the scan tool indicate the pre-catalyst HO2S voltages drop below 50 mV for the duration of system operation? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
Disconnect the vacuum hose from the inlet of the AIR solenoid valve. See SECONDARY AIR VACUUM CONTROL SOLENOID under MOTORS & SOLENOIDS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Connect a vacuum gage to the vacuum source. Start and idle the engine. Is engine vacuum displayed on the gage more than 10 in. Hg? If yes, go to next step. If no, go to step 32.
Turn ignition off. Disconnect the vacuum gage. Reconnect the vacuum hose to the inlet of the AIR solenoid valve. Disconnect the vacuum hose from the outlet of the AIR solenoid valve. Connect a vacuum gage to the outlet port of the AIR solenoid valve. Start and idle the engine. Command the AIR system on with a scan tool. Is the vacuum displayed on the gage more than 10 in. Hg? If yes, go to next step. If no, go to step 22.
Reconnect the vacuum hose to the AIR solenoid valve. Remove the vacuum hose from one of the AIR shut-off valves. Connect a vacuum gage to the vacuum hose. Command the AIR system on with a scan tool. Does the vacuum displayed on the gage indicate more than 10 in. Hg? If yes, go to next step. If no, go to step 32. Repeat procedure for the other shut-off valve. Ensure the vacuum hose is connected to the previous shut-off valve.
Connect a vacuum pump to one of the AIR shut-off valves. Apply 10 in. Hg of vacuum to the valve. Repeat procedure for the other shut-off valve. Do the shut-off valves hold vacuum for one minute? If yes, go to next step. If no, go to step 38.
Disconnect both intermediate hoses from the AIR shut-off valves. Start and idle the engine. Command the AIR system on with a scan tool. Is airflow present at both hoses? If yes, go to step 21. If no, go to next step.
Disconnect the outlet hose from the AIR pump. Command the AIR system on with a scan tool. Is there a powerful flow of air present at the outlet of the AIR pump? If yes, go to step 20. If no, go to next step.
Inspect the AIR pump inlet hose and filter for a restriction. Did you find and correct the condition? If yes, go to step 43. If no, go to step 41.
Inspect for a leak or restriction at the following components:
- The AIR outlet hose. See SECONDARY AIR INJECTION PUMP OUTLET PIPE/HOSE under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article.
- The AIR crossover hose. See SECONDARY AIR INJECTION CROSSOVER PIPE/HOSE under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article.
- The AIR intermediate hoses/pipes. See SECONDARY AIR INJECTION PUMP INTERMEDIATE PIPE/HOSE under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article.
Did you find and correct the condition? If yes, go to step 43. If no, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.

CAUTION: While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system.

Turn ignition off. Remove both of the shut-off valves from the shut-off valve outlet pipes. See SECONDARY AIR INJECTION SHUT-OFF VALVE under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Ensure that the vacuum hose and intermediate hoses are connected to the valves. Start and idle the engine. Command the AIR system on with a scan tool. Does airflow freely through each of the shut-off valves? If yes, go to step 36. If no, go to step 38.
Test the AIR solenoid valve control circuit and ignition 1 voltage circuit for high resistance. Did you find and correct the condition? If yes, go to step 43. If no, go to step 35.
Test the battery positive voltage circuit between the AIR pump fuse and the AIR pump relay for a short to ground. Replace the AIR pump fuse as necessary. Did you find and correct the condition? If yes, go to step 43. If no, go to step 25.
Test the AIR pump relay control circuit for a short to voltage. Replace the AIR pump fuse as necessary. Did you find and correct the condition? If yes, go to step 42. If no, see DIAGNOSTIC AIDS .
Replace the AIR fuse. Disconnect the AIR pump harness connector. Connect a test light between the AIR supply voltage circuit and the AIR pump ground circuit at the AIR pump harness connector. Does the test light illuminate? If yes, go to next step. If no, go to step 27.
Remove the AIR pump relay. Does the test light remain illuminated? If yes, go to step 28. If no, go to step 37.
Test the AIR pump supply voltage circuit for a short to ground. Replace the AIR pump fuse as necessary. Did you find and correct the condition? If yes, go to step 43. If no, go to step 41.
Test the AIR pump supply voltage circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 42. If no, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.
Repair the open circuit in the AIR pump battery positive circuit. Did you complete the repair? If yes, go to step 43.
Repair the open or high resistance in the AIR pump supply voltage circuit. Did you complete the repair? If yes, go to step 43.
Repair the open or high resistance in the AIR pump ground circuit. Did you complete the repair? If yes, go to step 43.
Inspect the vacuum source for any kinks, restrictions, splits, leaks or heat damage. Did you find and correct the condition? If yes, go to step 43. If no, go to step 40.
Test for an intermittent and/or poor connections at the AIR pump. Did you find and correct the condition? If yes, go to step 43. If no, go to step 41.
Test for an intermittent and/or poor connections at the AIR pump relay. Did you find and correct the condition? If yes, go to step 43. If no, go to step 37.
Test for an intermittent and/or poor connections at the AIR solenoid. Did you find and correct the condition? If yes, go to step 43. If no, go to step 39.

CAUTION: Allow the check valve to cool off before proceeding with the next check in order to avoid being burned. Tap on the check valve in order to remove any debris that may be inside the valve.

Repair the leak or restriction in the AIR shut-off valve outlet pipe and/or the exhaust manifold. Did you complete the repair? If yes, go to step 43.
Replace the AIR pump relay. Did you complete the replacement? If yes, go to step 42.
Replace the secondary AIR shut-off valve. See SECONDARY AIR INJECTION SHUT-OFF VALVE under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to step 43.
Replace the secondary AIR vacuum control solenoid. See SECONDARY AIR VACUUM CONTROL SOLENOID under MOTORS & SOLENOIDS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to step 43.
Replace the AIR vacuum check valve. Did you complete the replacement? If yes, go to step 43.
Replace the AIR pump. See SECONDARY AIR INJECTION PUMP under MOTORS & SOLENOIDS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to next step.
Replace the AIR Pump fuse as necessary. Ensure all connections and components are installed and connected. Command the AIR system on with a scan tool. Does the AIR pump turn on when commanded with a scan tool? If yes, go to next step. If no, go to step 2.
Clear the DTCs with a scan tool. Turn off the ignition for 30 seconds. Start and idle the engine. Operate the vehicle within the Conditions For Running 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 cycle? If yes, go to step 2. If no, go to next step.
Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.