Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Procedures
1996 Isuzu Trooper S, AutomaticSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 1996 Honda Passport. However, it is still accessible from the selected car via links, so may be relevant.
- Perform OBD-II System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
- Turn ignition on, engine off. Using scan tool, read EVAP VACUUM SW. If scan tool displays NO PURGE, go to next step. If scan tool does not display NO PURGE, go to DTC P1442.
- Turn engine on and allow it to idle. Using scan tool, read EVAP VACUUM SW. while commanding EVAP purge solenoid off. If scan tool displays NO PURGE, go to next step. If scan tool does not display NO PURGE, go to step 5).
- Turn ignition on, engine off. Using scan tool, read and record FAILS RECORD DATA. Operate vehicle within conditions noted in FAILED RECORDS DATA. Read SPECIFIC DTC. If scan tool displays DTC P1441 FAILED THIS IGN, go to next step. If scan tool does not display DTC P1441 FAILED THIS IGN, go to DIAGNOSTIC AIDS .
- Disconnect EVAP purge solenoid harness connector. Allow engine to idle. Read EVAP VACUUM SW. If scan tool displays NO PURGE, go to next step. If scan tool does not display NO PURGE, go to step 7).
- Turn ignition off. Disconnect PCM connectors. Check EVAP purge solenoid driver circuit for short to ground. If short to ground is found, repair as necessary and go to step 11). If no short is found, go tostep 8).
- Leave EVAP purge solenoid harness connector disconnected. Disconnect vacuum signal hose from EVAP purge vacuum switch. Connect a vacuum gauge to signal hose. Allow engine to idle. If vacuum is more than 5 in H(2)O, go to step 9). If vacuum is 5 in H(2)O or less, go to step 10).
- Replace PCM. Replacement PCM requires special equipment for programming procedures. Go to next step.
- Replace EVAP purge solenoid and go to step 11).
- Replace EVAP vacuum switch and go to next step.
- Read and record FAIL RECORDS data for DTC P1441. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1441 FAILED THIS IGN, return to step 2). If scan tool does not display DTC P1441 FAILED THIS IGN, repair is complete.
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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.