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.
2015 Subaru WRX BaseFACTORY OEM SERVICE PROCEDURE
Drive Cycle A
| DTC | Item | Condition |
|---|---|---|
| P0087 | Fuel Rail/System Pressure - Too Low | Complete diagnosis with drive cycle B or C as well. |
| P0088 | Fuel Rail/System Pressure - Too High | Complete diagnosis with drive cycle B or C as well. |
| P0128 | Coolant Thermostat (Engine Coolant Temperature Below Thermostat Regulating Temperature) | - |
| P0141 | O2 Sensor Heater Circuit (Bank1 Sensor2) | - |
| P014C | O2 Sensor Slow Response - Rich to Lean (Bank 1 Sensor 1) | - |
| P014D | O2 Sensor Slow Response - Lean to Rich (Bank 1 Sensor 1) | - |
| P015A | O2 Sensor Delayed Response - Rich to Lean (Bank 1 Sensor 1) | - |
| P015B | O2 Sensor Delayed Response - Lean to Rich (Bank 1 Sensor 1) | - |
| P0171 | System Too Lean (Bank 1) | Complete diagnosis with drive cycle B or C as well. |
| P0172 | System Too Rich (Bank 1) | Complete diagnosis with drive cycle B or C as well. |
| P0191 | Fuel Rail Pressure Sensor "A" Circuit Range/Performance | Complete diagnosis with drive cycle B or C as well. |
| P0300 | Random/Multiple Cylinder Misfire Detected | Complete diagnosis with drive cycle B or C as well. |
| P0301 | Cylinder 1 Misfire Detected | Complete diagnosis with drive cycle B or C as well. |
| P0302 | Cylinder 2 Misfire Detected | Complete diagnosis with drive cycle B or C as well. |
| P0303 | Cylinder 3 Misfire Detected | Complete diagnosis with drive cycle B or C as well. |
| P0304 | Cylinder 4 Misfire Detected | Complete diagnosis with drive cycle B or C as well. |
| P0420 | Catalyst System Efficiency Below Threshold (Bank 1) | - |
| P0459 | Evaporative Emission System Purge Control Valve Circuit High | - |
| P2096 | Post Catalyst Fuel Trim System Too Lean (Bank 1) | Complete diagnosis with drive cycle B or C as well. |
| P2097 | Post Catalyst Fuel Trim System Too Rich (Bank 1) | Complete diagnosis with drive cycle B or C as well. |
| P2195 | O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 1) | - |
| P2196 | O2 Sensor Signal Biased/Stuck Rich (Bank 1 Sensor 1) | - |
Diagnostic procedure:
- Drive for 20 minutes or more at a constant speed of 80 km/h (50 MPH) or more.
- Stop the vehicle and idle for one minute.
- Read the temporary code using the Subaru Select Monitor or general scan tool. <Ref. to OPERATION , Read Diagnostic Trouble Code (DTC).>
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.