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.
1997 Lexus SC 400FACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Self-Diagnostic System
- Scan Tool Problems
- Circuit Tests
- Notes
- DTC P0100 - Mass Airflow (MAF) Sensor Circuit
- DTC P0101 - Mass Airflow (MAF) Sensor Circuit Range/Performance Problem
- DTC P0110 - Intake Air Temperature (IAT) Sensor Circuit
- DTC P0115 - Engine Coolant Temperature (ECT) Sensor Circuit
- DTC P0116 - Engine Coolant Temperature (ECT) Sensor Circuit Range/Performance Problem
- DTC P0120 - Throttle Position (TP) Sensor Circuit Malfunction
- DTC P0121 - Throttle Position (TP) Sensor Circuit Range/Performance Problem
- DTC P0125 - Insufficient Coolant Temperature For Closed Loop Fuel Control
- DTC P0130, P0150 - Oxygen Sensor Related
- DTC P0133, O0153 - Oxygen Sensor Related
- DTC P0135, P0141, P0155, P0161 - Oxygen Sensor Related
- DTC P0136, P0156 - Oxygen Sensor Related
- DTC P0141 - Oxygen Sensor Related
- DTC P0150 - Oxygen Sensor Related
- DTC P0153 - Oxygen Sensor Related
- DTC P0155 - Oxygen Sensor Related
- DTC P0156 - Oxygen Sensor Related
- DTC P0161 - Oxygen Sensor Related
- DTC P0171, P0172 - Oxygen Sensor Related
- DTC P0300 - Random Misfire Detected
- DTCS P0301, P0308 - Cylinders No. 1-8 Misfire Detected
- DTC P0325, P0330 - Knock Sensor No. 1 & 2.
- DTC P0335, P1335 - Crankshaft Position (CKP) Sensor Circuit
- DTC P0340 - Camshaft Position (CMP) Sensor Circuit
- DTC P0401 - Insufficient Exhaust Gas RECIRCULATION (EGR) Flow Detected
- DTC P0402 - Excessive EGR Flow Detected
- DTC P0403 - EGR Circuit Malfunction
- DTC P0420, P0430 - Catalyst System Efficiency Below Threshold
- DTC P0440 - EVAP System Malfunction
- DTC P0441 - Incorrect EVAP Purge Flow DTC P0446 - Vent Control Malfunction
- DTC P0450 - Oxygen Sensor Related EVAP Pressure Sensor Malfunction
- DTC P0500 - Vehicle Speed Sensor (VSS) Malfunction
- DTC P0505 - Idle Control System Malfunction
- DTC P0510 - Closed Throttle Position (CTP) Switch Malfunction
- DTC P1100 - Barometric Pressure (BARO) Sensor Circuit Malfunction
- DTC P1200 - Fuel Pump Relay Circuit Malfunction
- DTC P1300, P1305 - IGNITOR Circuit Malfunction
- DTC P1335 - Crankshaft Position (CKP) Sensor Circuit
- DTC P1400 - Sub-Throttle Position (Sub-TP) Sensor Malfunction
- DTC P1401 - Sub-Throttle Position (Sub-TP) Sensor Circuit Range/Performance Problem
- DTC P1520 - Stoplight Switch Signal Malfunction
- DTC P1600 - ECM Batt Malfunction
- DTC P1605 - Knock Control ECM Malfunction
- DTC P1780 - Park/Neutral Position Switch Malfunction
- Summary
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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