Mainstream Platform Telemetry

Subaru OBD-II Diagnostics & Fault Codes

Factory diagnostic trouble code directory for Subaru vehicles (Outback, Forester, Crosstrek, WRX, Ascent). Access model-specific sensor tolerances, live freeze-frame telemetry, and verified DIY repair procedures.

Reliability Index

High

Industry Standard

Dealership Labor Rate

$115/hr

National Average

Avg. Sensor Cost

$95 - $165

OEM Direct Replacement

Protocol Standards

ISO 15765-4 CAN

SAE J1979 Compliant

Model Selection

Select Your Subaru Model (2 Supported)

Mainstream

2020–2026SUV

Subaru Outback

2.5L Boxer-4 (FB25D 182HP) / 2.4L Turbocharged Boxer-4 (FA24F 260HP XT)

DLC Port GuideDTC Codes

Mainstream

2020–2026SUV

Subaru Forester

2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD)

DLC Port GuideDTC Codes

Brand Telemetry

Most Common Subaru Check Engine Trouble Codes

P0420Subaru Specific

Est. DIY Parts: $400 - $1,800 (DIY: $150 - $400)

P0420 on Subaru: Symptoms & Fix

Factory troubleshooting procedure for P0420: P0420: Catalyst System Efficiency Below Threshold (Bank 1) specifically affecting Subaru (Outback, Forester).

5-Step OEM FixDiagnose Subaru

P0300Subaru Specific

Est. DIY Parts: $100 - $600 (DIY: $30 - $120)

P0300 on Subaru: Symptoms & Fix

Factory troubleshooting procedure for P0300: P0300: Random or Multiple Cylinder Misfire Detected specifically affecting Subaru (Outback, Forester).

5-Step OEM FixDiagnose Subaru

P0171Subaru Specific

Est. DIY Parts: $80 - $350 (DIY: $15 - $70)

P0171 on Subaru: Symptoms & Fix

Factory troubleshooting procedure for P0171: P0171: System Too Lean (Bank 1) specifically affecting Subaru (Outback, Forester).

5-Step OEM FixDiagnose Subaru

P0128Subaru Specific

Est. DIY Parts: $120 - $300 (DIY: $25 - $60)

P0128 on Subaru: Symptoms & Fix

Factory troubleshooting procedure for P0128: P0128: Coolant Temperature Below Thermostat Regulating Temperature specifically affecting Subaru (Outback, Forester).

5-Step OEM FixDiagnose Subaru

P0442Subaru Specific

Est. DIY Parts: $25 - $200 (DIY: $15)

P0442 on Subaru: Symptoms & Fix

Factory troubleshooting procedure for P0442: EVAP System Small Leak Detected - Diagnosis & Repair Guide specifically affecting Subaru (Outback, Forester).

5-Step OEM FixDiagnose Subaru

P0500Subaru Specific

Est. DIY Parts: $140 - $340 (DIY: $30 - $75)

P0500 on Subaru: Symptoms & Fix

Factory troubleshooting procedure for P0500: P0500: Vehicle Speed Sensor (VSS) Malfunction specifically affecting Subaru (Outback, Forester).

5-Step OEM FixDiagnose Subaru

Full Diagnostic Library

All OBD-II Codes for Subaru

Showing 1–18 of 122 codes

Active:

1. Filter by Vehicle Manufacturer (25 Makes)

2. DTC System Category

3. Risk Severity Level

P0300Critical Severity

Est. DIY: $100 - $600 (DIY: $30 - $120)

P0300: Random or Multiple Cylinder Misfire Detected

Flashing Check Engine Light (CEL) • Engine shaking, vibrating, or jerking at idle

5 Step DIY GuideTroubleshoot

P0420Medium Severity

Est. DIY: $400 - $1,800 (DIY: $150 - $400)

P0420: Catalyst System Efficiency Below Threshold (Bank 1)

Illuminated Check Engine Light (steady) • Rotten egg / sulfur odor from exhaust

5 Step DIY GuideTroubleshoot

P0171Medium Severity

Est. DIY: $80 - $350 (DIY: $15 - $70)

P0171: System Too Lean (Bank 1)

Check Engine Light on • Rough idling or engine hesitation on acceleration

5 Step DIY GuideTroubleshoot

P0128Low Severity

Est. DIY: $120 - $300 (DIY: $25 - $60)

P0128: Coolant Temperature Below Thermostat Regulating Temperature

Check Engine Light • Cabin heater takes too long to warm up

5 Step DIY GuideTroubleshoot

P0455Low Severity

Est. DIY: $15 - $250 (DIY: $15 - $50)

P0455: Evaporative Emission Control System Leak Detected (Gross Leak)

Check Engine Light on • Gas cap loose warning message on dashboard

5 Step DIY GuideTroubleshoot

P0101Medium Severity

Est. DIY: $45 - $220 (DIY Clean: $12)

Mass Air Flow (MAF) Sensor Circuit Range/Performance

Check Engine Light (CEL) illuminated • Rough or erratic engine idle

4 Step DIY GuideTroubleshoot

P0135Low to Medium Severity

Est. DIY: $80 - $240 (DIY Sensor: $45)

O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)

Check Engine Light on • Slightly increased fuel consumption on short trips

3 Step DIY GuideTroubleshoot

P0172Medium Severity

Est. DIY: $30 - $280 (DIY Clean: $15)

System Too Rich (Bank 1) - Symptoms, Causes & Step-by-Step Fix

Check Engine Light on • Strong unburnt fuel odor from exhaust

3 Step DIY GuideTroubleshoot

P0442Low Severity

Est. DIY: $25 - $200 (DIY: $15)

EVAP System Small Leak Detected - Diagnosis & Repair Guide

Check Engine Light on • Intermittent faint fuel odor near rear wheel well

3 Step DIY GuideTroubleshoot

P0507Medium Severity

Est. DIY: $40 - $250 (DIY Throttle Relearn: $0)

Idle Control System RPM Higher Than Expected - Diagnosis

Engine idles at 1,000+ RPM in park/neutral • RPM surges or hunts at red lights

3 Step DIY GuideTroubleshoot

P0010Moderate Severity

Est. DIY: $120 - $350 (DIY: $40 - $80)

P0010: Camshaft Position Actuator Circuit / Open (Bank 1)

System alert or indicator light illuminated (P0010) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

P0011High Severity

Est. DIY: $150 - $450 (DIY: $50 - $120)

P0011: Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)

System alert or indicator light illuminated (P0011) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

P0012High Severity

Est. DIY: $150 - $450 (DIY: $50 - $120)

P0012: Camshaft Position - Timing Over-Retarded (Bank 1)

System alert or indicator light illuminated (P0012) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

P0013Moderate Severity

Est. DIY: $120 - $320 (DIY: $40 - $75)

P0013: Exhaust Camshaft Position Actuator Circuit / Open (Bank 1)

System alert or indicator light illuminated (P0013) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

P0014High Severity

Est. DIY: $150 - $420 (DIY: $45 - $90)

P0014: Exhaust Camshaft Position Timing Over-Advanced (Bank 1)

System alert or indicator light illuminated (P0014) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

P0016Critical Severity

Est. DIY: $300 - $1,200 (DIY: $80 - $250)

P0016: Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A)

System alert or indicator light illuminated (P0016) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

P0017Critical Severity

Est. DIY: $300 - $1,200 (DIY: $80 - $250)

P0017: Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B)

System alert or indicator light illuminated (P0017) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

P0100Moderate Severity

Est. DIY: $100 - $300 (DIY: $15 - $80)

P0100: Mass or Volume Air Flow Circuit Malfunction

System alert or indicator light illuminated (P0100) • Intermittent performance throttling or unexpected operation halts

5 Step DIY GuideTroubleshoot

Technical FAQ

Frequently Asked Questions

What are the most common Check Engine fault codes on Subaru vehicles?

On Subaru vehicles, the most frequently logged diagnostic trouble codes are P0420 (Catalytic Converter Efficiency), P0300 (Random Misfire), P0171 (System Lean), and P0128 (Coolant Thermostat).

How much does a dealer diagnostic scan cost for a Subaru?

Standard diagnostic fees at authorized Subaru dealerships range from $120 to $180, aligned with their $115/hr standard hourly labor rate. Independent auto parts stores can read codes for free.

Can I clear a Subaru Check Engine light with an OBD-II scanner?

Yes, any standard OBD-II / EOBD scanner connected to the 16-pin DLC port can clear logged DTC codes and turn off the Check Engine light once the underlying mechanical defect has been resolved.