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.
1987 Isuzu Impulse Base, Standard, MSG4KFACTORY OEM SERVICE PROCEDURE
I-TEC Control System
- Description
- Operation
- Diagnosis & Testing
- Preliminary Inspection
- Diagnostic Procedure
- Diagnostic Tools
- Circuit Inspection
- Test 1 - Power Supply Check
- Test 2 - Oxygen Sensor (Codes 13, 44 And 45)
- Test 3 - Coolant Temperature Sensor (Codes 14, 15 And 16)
- Test 4 - Throttle Valve Switch (Codes 21, 43 And 65)
- Test 5 - Starter Signal (Code 22)
- Test 6 - Crank Angle Sensor (Code 41)
- Test 7 - Airflow Sensor (Codes 61 And 62)
- Test 8 - Vehicle Speed Sensor (Code 63)
- Test 9 - Knock Sensor (Code 66)
- Test 10 - Ecu (Codes 51, 52 And 55)
- Test 11 - Power Transistor System (Codes 23, 35 And 54)
- Test 12 - Vacuum Switching Valve (Code 25 And 53)
- Test 13 - Fuel Injector Circuits (Code 33)
- Test 14 - Injector Transistor Ground Circuit (Code 64)
- Test 15 - Vacuum Switching Valve Circuit (Code 71, 72, And 73)
- Wiring Diagrams
Factory Service Tools
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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.
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