Check Engine Light Just Came On — Here Is What to Do First
Steady CEL vs flashing CEL changes everything. Here is how to triage a check engine light, get a free scan, and decide if you can keep driving.
Apr 11, 2026 10 min read
Vehicle Diagnostics
OBD2 scanners, fault code interpretation, and DIY repair guides. I diagnose cars the same way I diagnose network issues — methodically.
#OBD2 Scanners#Fault Codes#Subaru#DIY Repair#Battery#Fuel System#EPB Service
Got a fault code?
Look it up in our OBD2 code database — 200+ codes with causes, symptoms, and fix procedures.
How to Use Live Data on Your OBD2 Scanner — the Values That Actually Matter
Codes tell you where to look. Live data tells you what is actually happening. Learn the key PIDs, normal ranges, and how to read fuel trims correctly.
Apr 11, 2026 7 min read
How to Reset TPMS Sensors After a Tire Rotation or New Tires
TPMS light on after a rotation? Learn how direct and indirect systems work and the right reset method for your vehicle before you make it worse.
Apr 11, 2026 6 min read
How to Test Your Car Battery and Alternator with a Multimeter
Resting voltage, cranking drop, charging voltage at idle and 2000 RPM — here is every test you need to diagnose a battery or alternator problem.
Apr 11, 2026 11 min read
OBD2 Readiness Monitors Explained: Why Your Car Fails Emissions After a Repair
Learn what OBD2 readiness monitors are, why they reset after a repair, and how to complete a drive cycle before your emissions test.
Apr 11, 2026 6 min read
P0128 — Coolant Temperature Below Thermostat Regulating Temperature
P0128 almost always means a stuck-open thermostat, not a bad sensor. Learn how to confirm it with live data and why ignoring it costs you fuel and heat.
Apr 11, 2026 6 min read
P0300 Random Misfire Diagnosis Guide — How to Find It and Fix It
P0300 means the ECM cannot pin the misfire on one cylinder. Here is how to isolate the cause using live data, swap tests, and compression checks.
Apr 11, 2026 12 min read
P0401: EGR Flow Insufficient — How to Diagnose and Fix It Right
P0401 means insufficient EGR flow, not no flow. Here's how to test the valve, find the real cause, and avoid the mistake that makes it come back.
Apr 11, 2026 7 min read
P0442 — EVAP Small Leak Diagnosis Guide
P0442 means a small EVAP leak detected. Here is what the system does, why the code comes back, and how to find and fix the actual leak.
Apr 11, 2026 6 min read
Timing Belt vs Timing Chain — When to Replace and What Happens If You Don't
Know whether your engine has a belt or chain, what the replacement intervals are, and what a skipped service actually costs you.
Apr 11, 2026 6 min read
P0420 Code: Is It Really the Catalytic Converter? (Usually Not Immediately)
P0420 doesn't always mean a dead cat. Rule out exhaust leaks, O2 sensors, and running conditions before spending $1,200 on a converter.
Dec 5, 2025 12 min read
How to Read OBD2 Codes for Free Using Your Phone
Read OBD2 codes with your phone using a Bluetooth adapter and free app. What works, what doesn't, and the adapter trap to avoid on iPhone.
Nov 17, 2025 10 min read
P0171 System Too Lean: How to Find the Real Cause Without Guessing
P0171 means more air than fuel on Bank 1. Use LTFT live data, smoke test, and MAF cleaning before touching anything else.
Nov 10, 2025 11 min read
Best OBD2 Scanners for Subaru Owners (2026 Comparison)
Subaru uses manufacturer-specific codes cheap scanners miss. Comparison of the best OBD2 scanners for Subaru: Foxwell, BlueDriver, Autel, iCarsoft.
Nov 1, 2025 10 min read
Featured
Subaru P1604 Code: What It Means and How to Fix It
The P1604 code means Startability Malfunction — often caused by a weak battery. Here's what's actually happening, how to diagnose it, and the correct fix.
Oct 8, 2025 7 min read