Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. 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.
Observe the Freeze Frame/Failure Records for this DTC. Perform the Service Bay Test. See INSPECTION/MAINTENANCE EVAPORATIVE EMISSION SYSTEM SET PROCEDURE under SELF-DIAGNOSTIC SYSTEM. Does the scan tool indicate that the Service Bay Test passed? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
Inspect the EVAP system for the following conditions:
- A damaged EVAP vent valve.
- A pinched EVAP vent hose.
- A damaged EVAP canister.
Did you find and correct the condition? If yes, go to step 14. If no, go to next step.
Disconnect the purge pipe from the EVAP purge valve. Turn ignition ON, with engine OFF. Observe the fuel tank pressure parameter with a scan tool. Is the Fuel Tank Pressure sensor parameter within -1 to 1 in. H2O? If yes, go to next step. If no, go to step 9.

NOTE: Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.

1. Turn ignition OFF.
2. Reconnect the EVAP purge pipe.
3. Connect the Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source.
4. Install the Fuel Tank Cap Adapter to the fuel fill pipe.
5. Connect the fuel fill cap to the Fuel Tank Cap Adapter.
6. Connect the EEST nitrogen/smoke supply hose to the Fuel Tank Cap Adapter.
7. Turn ignition ON, with engine OFF.
8. Command the EVAP vent valve closed with a scan tool.
9. Turn the nitrogen/smoke valve on the EEST control panel to NITROGEN.
10. Use the remote switch to pressurize the EVAP system to 5 in. H2O.
11. Observe the Fuel Tank Pressure sensor parameter with a scan tool.
12. Command the EVAP vent valve open with a scan tool.
Is the Fuel Tank Pressure sensor parameter less than 1 in. H2O? If yes, go to DIAGNOSTIC AIDS . If no, go to next step.
Disconnect the EVAP vent hose from the EVAP vent valve. Is the Fuel Tank Pressure sensor parameter less than 1 in. H2O? If yes, go to step 11. If no, go to next step.
Disconnect the EVAP vent hose from the EVAP canister. Does the scan tool indicate fuel tank pressure near 1 in. H2O? If yes, go to next step. If no, go to step 12.
Repair for a blockage in the EVAP vent hose. Did you complete the repair? If yes, go to step 13.
Test for an intermittent and/or poor connections at the FTP sensor. Did you find and correct the condition? If yes, go to step 13. If no, go to next step.
Replace FTP sensor. See FUEL TANK PRESSURE SENSOR under SENSORS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to step 13.
Replace the EVAP vent valve. See EVAP CANISTER VENT VALVE under SOLENOIDS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to step 13.
Replace the EVAP canister. See EVAP CANISTER under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to next step.
Reconnect all of the EVAP hardware that was previously disconnected. Perform the Service Bay Test. See INSPECTION/MAINTENANCE EVAPORATIVE EMISSION SYSTEM SET PROCEDURE under DRIVE CYCLES. Does the scan tool indicate that the Service Bay Test has passed? If yes, go to next step. If no, go to step 3.
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.