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.
1999 Lexus RX 300 FWDFACTORY OEM SERVICE PROCEDURE
Engine Performance DTCS
ENGINE PERFORMANCE DIAGNOSTIC TROUBLE CODES (DTC) IDENTIFICATION
| DTC | Description |
|---|---|
| P0100 | Mass Airflow (MAF) Sensor Circuit |
| P0101 | Mass Airflow (MAF) Sensor Circuit Range/Performance Fault |
| P0110 | Intake Air Temperature (IAT) Sensor Circuit |
| P0115 | Engine Coolant Temperature (ECT) Sensor Circuit |
| P0116 | Engine Coolant Temperature (ECT) Sensor Circuit Range/Performance Fault |
| P0120 | Throttle Position (TP) Sensor Circuit Malfunction |
| P0121 | Throttle Position (TP) Sensor Circuit Range/Performance Fault |
| P0125 | Insufficient Coolant Temperature For Closed Loop Fuel Control |
| P0136 | Heated Oxygen Sensor Circuit |
| P0141 | Heated Oxygen Sensor Heater Circuit |
| P0171 | System Too Lean |
| P0172 | System Too Rich |
| P0300 | Random Cylinder Misfire Detected |
| P0301 | Cylinder No. 1 Misfire Detected |
| P0302 | Cylinder No. 2 Misfire Detected |
| P0303 | Cylinder No. 3 Misfire Detected |
| P0304 | Cylinder No. 4 Misfire Detected |
| P0305 | Cylinder No. 5 Misfire Detected |
| P0306 | Cylinder No. 6 Misfire Detected |
| P0325 | Knock Sensor |
| P0330 | Knock Sensor |
| P0335 | Crankshaft Position (CKP) Sensor Circuit |
| P0340 | Camshaft Position (CMP) Sensor Circuit |
| P0420 | Catalyst System |
| P0440 | EVAP System Malfunction |
| P0441 | Incorrect EVAP Purge Flow |
| P0446 | EVAP Vent Control Fault |
| P0450 | EVAP Pressure Sensor Malfunction |
| P0451 | EVAP Pressure Sensor Range/Performance Fault |
| P0500 | Vehicle Speed Sensor (VSS) Malfunction |
| P0505 | Idle Control System Malfunction |
| P1130 | Air/Fuel Sensor Circuit Range/Performance Fault |
| P1133 | Air/Fuel Sensor Circuit Response Malfunction |
| P1135 | Air/Fuel Sensor Heater Circuit Malfunction |
| P1150 | Air/Fuel Sensor Circuit Range/Performance Fault |
| P1153 | Air/Fuel Sensor Circuit Response Malfunction |
| P1155 | Air/Fuel Sensor Heater Circuit Malfunction |
| P1300 | Ignitor Circuit Malfunction (No. 1) |
| P1305 | Ignitor Circuit Malfunction (No. 2) |
| P1310 | Ignitor Circuit Malfunction (No. 3) |
| P1315 | Ignitor Circuit Malfunction (No. 4) |
| P1320 | Ignitor Circuit Malfunction (No. 5) |
| P1325 | Ignitor Circuit Malfunction (No. 6) |
| P1335 | Crankshaft Position (CKP) Sensor Circuit |
| P1345 | Variable Valve Timing (VVT) Circuit Fault |
| P1346 | Variable Valve Timing (VVT) Circuit Range/Performance Fault |
| P1349 | Variable Valve Timing (VVT) System Malfunction |
| P1350 | Variable Valve Timing (VVT) Circuit Malfunction |
| P1351 | Variable Valve Timing (VVT) Circuit Range/Performance Fault |
| P1354 | Variable Valve Timing (VVT) System Malfunction |
| P1520 | Stoplight Switch Signal Malfunction |
| P1600 | ECM Batt Malfunction |
| P1645 | Body ECU Malfunction |
| P1656 | Oil Control Valve (OCV) Malfunction |
| P1663 | Oil Control Valve (OCV) Malfunction |
| P1780 | Park/Neutral Position Switch Malfunction |
Factory Service Tools
Use the Manual With the Right Hardware
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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.