Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Isuzu Rodeo Sport and 2002 Isuzu Rodeo. However, it is still accessible from the selected car via links, so may be relevant.
- Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
- If DTC P0461, P0462 or P0463 are also set, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If specified DTCs are not set, go to next step.
- Perform a visual and physical inspection of fuel cap. If problem is found, replace as necessary. After repair, go to step 20 . If no problem is found, go to next step.
- Using scan tool, select EVAPORATIVE SYSTEMS TEST under MISCELLANEOUS TESTS. From scan tool, command EVAP canister purge control valve and vent solenoid On and off. Ensure purge valve and vent solenoid click audibly when commanded on and off with scan tool. If click is heard, go to next step. If no click is heard, inspect components and verify PCM output signal to each component. See appropriate pin voltage chart in PIN VOLTAGE CHARTS article.
- Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, observe FUEL TANK PRESSURE voltage parameter. If parameter is 1.51 volts, go to step 8 . If parameter is not as specified, go to next step.
- If battery has been disconnected, perform a visual and physical inspection of EVAP system. See EVAPORATIVE EMISSION SYSTEM in SYSTEM & COMPONENT TESTING article. If battery was not disconnected, go to next step.
- Disconnect battery. Wait at least 20 seconds, and reconnect battery. Repeat test starting in step 5 .
- Install fuel cap. Using scan tool, select EVAPORATIVE SYSTEMS TEST under MISCELLANEOUS TESTS. From scan tool, command EVAP vent solenoid On (closed). Connect EVAP pressure/vacuum gauge to EVAP service port. Using EVAP pressure/purge testing cart attempt to pressurize EVAP system to 5 in. H2 O. If 5 in. H2 O pressure can be achieved, go to next step. If 5 in. H2 O pressure cannot be achieved, go to step 10 .
- On scan tool observe FUEL TANK PRESSURE parameter. If pressure is maintained between 1.47-1.51 volts, go to step 12 . If pressure cannot be maintained, go to step 11 .
- Disconnect fuel tank vapor line and EVAP purge line from EVAP canister. EVAP canister is located on frame rail, under vehicle. Block canister fitting for fuel tank vapor line. Connect a hand vacuum pump to canister fitting for EVAP purge line. Ensure EVAP vent solenoid is still commanded On (closed). Apply 5 in. Hg to EVAP canister. If vacuum can be maintained, go to step 15 . If vacuum cannot be maintained, go to step 14 .
- Perform a complete visual and physical inspection of EVAP system. Check for restricted fuel tank vapor line, and a restricted EVAP purge line. If problem is found, repair as necessary. After repair, go to step 20 . If no problems are found, go to EVAPORATIVE EMISSION SYSTEM in SYSTEM & COMPONENT TESTING article.
- Disconnect vacuum line from between throttle body and EVAP canister. Connect hand vacuum pump to EVAP canister purge valve vacuum fitting. Apply 10 in. Hg to EVAP canister purge valve. From scan tool, command EVAP purge valve On. If vacuum is released, go to next step. If vacuum is not released, go to step 17 .
- Connect pressure/vacuum gauge to vacuum source line to EVAP canister purge valve. Start engine and hold speed at 2500 RPM. While observing vacuum gauge, quickly depress accelerator pedal and allow engine to return to idle. If vacuum gauge reads 10 in. Hg or more when throttle was opened and closed, go to DIAGNOSTIC AIDS . If vacuum reading was not as specified, go to step 18 .
- Perform a visual and physical inspection of EVAP system. Check for disconnected or damaged EVAP vent hose. Check for damaged EVAP canister. If problem is found, repair any damaged EVAP components as necessary. After repair, go to step 20 . If no problem is found, go to step 19 .
- Perform a visual and physical inspection of EVAP system. Check for missing, damaged or defective gas cap, vapor lines or EVAP purge line. If problem is found, repair as necessary. After repair, go to step 20 . If no problem was found, go to next step.
- Using scan tool, command EVAP vent solenoid On. Using EVAP pressure/purge testing cart attempt to pressurize EVAP system. Turn EVAP service cart pressure knob in pressurized position. Using ultrasonic leak detector, locate and repair any leaks in EVAP system (it may be necessary to partially lower fuel tank to locate leaks). If problem is found, repair as necessary. After repair, go to step 20 .
- Replace EVAP canister purge valve. After repair, go to step 20 .
- Located and repair cause of no source vacuum to EVAP canister purge valve. After repair, go to step 20 .
- Replace EVAP vent solenoid. After repair, go to step 20 .
- Turn ignition on. Using scan tool, command EVAP vent solenoid On (closed). Connect EVAP pressure/vacuum gauge to EVAP service port. Using EVAP pressure/purge testing cart attempt to pressurize EVAP system to 15 in. H2 O. Rotate switch on EVAP Diagnostic Station to hold position. On scan tool, observe FUEL TANK PRESSURE voltage parameter. If voltage decreases to less than 2.14 volts within 2 minutes, system is okay. If voltage does not decrease as specified, repeat test starting in step 3 .
NOTE:
Calibrate EVAP pressure/vacuum gauges on EVAP pressure/purge testing cart (J41413) or equivalent before proceeding. See manufacturer's operating instructions.
NOTE:
Review temperature variation instructions included with EVAP Diagnostic Station pressure and vacuum gauge operating instructions before proceeding.