Is your 1999 Subaru’s check engine light illuminated? Don’t panic. Your car’s On-Board Diagnostics II (OBD2) system is designed to alert you to potential issues. This system generates specific diagnostic trouble codes (DTCs), often referred to as OBD2 codes, that pinpoint the problem area. Understanding these 1999 Subaru Obd2 Codes can help you diagnose and address the underlying issue, saving you time and potentially costly repairs. This guide provides a comprehensive list of common 1999 Subaru OBD2 codes and their potential causes.
Common 1999 Subaru OBD2 Codes and Their Meanings
The following table lists common OBD2 codes that can occur in a 1999 Subaru, along with their potential causes. Remember, these are just potential causes, and a proper diagnosis with an OBD2 scanner is recommended.
| Code | Potential Problems |
|---|---|
| P0101 | Mass Air Flow (MAF) sensor issues, vacuum leaks, intake manifold gasket problems. |
| P0102 | MAF sensor circuit malfunction, wiring issues, faulty MAF sensor. |
| P0113 | Intake Air Temperature (IAT) sensor issues, dirty air filter, faulty MAF sensor. |
| P0128 | Thermostat malfunction, coolant temperature sensor issues, low coolant level. |
| P0135 | Oxygen sensor heater circuit malfunction, exhaust leaks, wiring problems. |
| P0171 | Lean air/fuel mixture, vacuum leaks, faulty MAF sensor, fuel system issues. |
| P0174 | Lean air/fuel mixture (Bank 2), similar causes to P0171. |
| P0300 | Random/multiple cylinder misfire, spark plugs, ignition coils, fuel delivery. |
| P0301 | Cylinder 1 misfire, same potential causes as P0300, but specific to cylinder 1. |
| P0302 | Cylinder 2 misfire – similar to P0301 but for cylinder 2. |
| P0303 | Cylinder 3 misfire – similar to P0301 but for cylinder 3. |
| P0304 | Cylinder 4 misfire – similar to P0301 but for cylinder 4. |
| P0401 | Insufficient Exhaust Gas Recirculation (EGR) flow, EGR valve or solenoid issues. |
| P0420 | Catalyst System Efficiency Below Threshold (Bank 1), often indicates a faulty catalytic converter. |
| P0440 | Evaporative Emission Control System (EVAP) leak, loose gas cap, EVAP system component failure. |
| P0442 | Small EVAP leak, similar causes to P0440 but often a smaller leak. |
| P0500 | Vehicle Speed Sensor (VSS) malfunction, wiring issues, faulty VSS. |
| P0505 | Idle Air Control (IAC) system malfunction, vacuum leaks, faulty IAC valve. |
| P0700 | Transmission control system malfunction, often indicated by other transmission-related codes. |
Diagnosing 1999 Subaru OBD2 Codes
While this list provides a starting point, using an OBD2 scanner is crucial for accurate diagnosis. The scanner will display the specific code(s) stored in your car’s computer.
Subaru-Specific Codes and Professional Help
Remember that some codes, particularly those starting with “P1,” are specific to Subaru. These codes require specialized knowledge and diagnostic equipment.
Conclusion: Taking Action with Your 1999 Subaru OBD2 Codes
Don’t ignore your check engine light. Addressing 1999 Subaru OBD2 codes promptly can prevent minor issues from becoming major problems. While this guide offers valuable information, consulting a qualified mechanic, especially for Subaru-specific codes, is always recommended for accurate diagnosis and repair. A professional can utilize advanced diagnostic tools and their expertise to ensure your Subaru is repaired correctly.
