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.
1998 Lexus LX 470FACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Diagnostic Trouble Code Definitions
- Self-Diagnostic Tests
- * Please Read First *
- 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 Fault
- DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control
- DTC P0130 Or P0150: Heated Oxygen Circuit (Sensor No. 1)
- DTC P0133 Or P0153: Heated Oxygen Sensor Circuit (Sensor No. 1) Slow Response
- DTC P0135 Or P0155: Heated Oxygen Sensor Heater Circuit
- DTC P0136 Or P0156: Heated Oxygen Sensor Circuit (Sensor No. 2)
- DTC P0141 Or P0161: Heated Oxygen Sensor Heater Circuit
- DTC P0171: System Too Lean (Fuel Trim) DTC P0172: System Too Rich (Fuel Trim)
- DTC P0300: Random Misfire Detected
- DTCS P0301-P0308: Cylinders No. 1-8 Misfire Detected
- DTC P0325: Knock Sensor No. 1 Circuit DTC P0330: Knock Sensor No. 2 Circuit
- DTC P0335 Or P1335: Crankshaft Position (CKP) Sensor "A" Circuit
- DTC P0340: Camshaft Position (CMP) Sensor Circuit
- DTC P0420 Or P0430: Catalyst System Efficiency Below Threshold
- DTC P0440: Evaporative Emission Control System Malfunction
- DTC P0441: Incorrect EVAP Purge Flow DTC P0446: Vent Control Malfunction
- DTC P0450: EVAP Pressure Sensor Fault DTC P0451: EVAP Pressure Sensor Range/Performance
- DTC P0500: Vehicle Speed Sensor Fault
- DTC P0505: Idle Air Control (IAC) System Malfunction
- DTC P1120: Accelerator Pedal Position (App) Sensor Circuit Fault
- DTC P1121: Accelerator Pedal Position (App) Sensor Range/Performance Fault
- DTC P1125: Throttle Control Motor Circuit Malfunction
- DTC P1126: Magnetic Clutch Circuit Malfunction
- DTC P1127: Electronic Throttle Control System Actuator Power Source Circuit Fault
- DTC P1128: Throttle Control Motor Lock Malfunction
- DTC P1129: Electronic Throttle Control System Fault
- DTC P1200: Fuel Pump Relay/Ecu Circuit Fault
- DTC P1300: IGNITOR Circuit Malfunction
- DTC P1305: IGNITOR Circuit Malfunction
- DTC P1310: IGNITOR Circuit Malfunction
- DTC P1315: IGNITOR Circuit Malfunction
- DTC P1320: IGNITOR Circuit Malfunction
- DTC P1325: IGNITOR Circuit Malfunction
- DTC P1330: IGNITOR Circuit Malfunction
- DTC P1335: Crankshaft Position (CKP) Sensor Circuit
- DTC P1340: IGNITOR Circuit Malfunction
- DTC P1520: Stoplight Switch Signal Malfunction (A/T Only)
- DTC P1600: ECM Batt Malfunction
- DTC P1633: ECM Malfunction (Electronic Throttle Control System Circuit)
- DTC P1780: Park/Neutral Position (PNP) Switch
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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