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 On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
- Using scan tool, select LAST TEST FAIL. Record any other failed DTCs. If any DTC other than P1153 or P1154 sets, diagnose affected DTC before proceeding. If no other DTC sets, start engine and allow it to idle. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1133 FAILED THIS IGN, go to next step. If scan tool does not display DTC P1133 FAILED THIS IGN, go to DIAGNOSTIC AIDS .
- Using scan tool, select LAST TEST FAIL. Record any other failed DTCs. If DTC P1153 and P1154 is also set, go to step 11). If DTC is not set, go to next step.
- Check exhaust system for leaks. If exhaust leak is found, repair as necessary and go to step 2). If no exhaust leak is found, go to next step.
- Visually inspect HO2S 1 for secure installation or corrosion on terminals. Check terminal tension at HO2S 1 and PCM. Check for damaged wiring. If a problem is found, go to step 14). If no problem is found, go to next step.
- Disconnect HO2S 1 connector. Connect a DVOM to PCM side of connectors high signal and ground, and low signal and ground. Turn ignition on and read DVOM at each connection. If reading is 3-4 volts, go to step 9). If voltage is not as specified, go to next step.
- Turn ignition off and check for damage to PCM pins or terminals. If a problem was found repair as necessary and go to step 14). If no problem was found, go to next step.
- Inspect signal circuit for a short to voltage, ground or an open. If problem was found repair as necessary and go to step 14). If no problem was found, go to next step.
- With ignition off, disconnect PCM connector. Disconnect HO2S and check for high and low signal circuits, located between PCM and HO2S, for shorting together. If a problem was found, repair as necessary and go to step 14). If no problem was found, go to next step.
- Connect PCM and disconnected Bank 1 HO2S 1. Using scan tool check voltage. If reading is .43-.47 volts, go to step 12), If voltage is not as specified, got step 13).
- Check for fuel contamination, use of improper RTV sealant or engine oil and coolant consumption. Replace affected HO2S and go to step 14).
- Replace HO2S 1 and go to step 14).
- Replace PCM. Program replacement PCM using required equipment. Go to next step.
- Using scan tool, read and record FAIL RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P1133. If scan tool displays DTC P1133 FAILED THIS IGN, return to step 2). If scan tool does not display DTC P1133 FAILED THIS IGN, repair is complete.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.