Check Engine Light Diagnostics in Pasadena & Hollywood

A code is a starting point, not an answer

The free code read at a parts counter gives you something like P0171 — System Too Lean, Bank 1. That is a symptom shared by a vacuum leak, a failing mass airflow sensor, a weak fuel pump, a dirty injector or a bad oxygen sensor. Replacing parts until the light goes off is an expensive way to guess.

Our diagnostic process pulls the codes and the freeze-frame data, then tests the actual circuit — live data, fuel trims, smoke testing for vacuum leaks, and scope work where it's needed — until we can point at the failed component and explain why.

What we diagnose

• Check engine, service engine soon and emissions warning lights
• Misfires, rough idle, hesitation and stalling
• Oxygen sensor, MAF and MAP sensor faults
• Catalytic converter efficiency codes
• EVAP and fuel system leaks
• Ignition system, coil and spark plug faults
• ABS, airbag and transmission warning lights
• Battery, alternator and starting/charging faults
• Pre-smog diagnosis before a California emissions test

Flashing light vs. steady light

A steady check engine light means a fault is stored and should be looked at soon, but the car is generally drivable. A flashing check engine light means an active misfire is dumping raw fuel into the exhaust and can destroy a catalytic converter in a short drive. If yours is flashing, stop driving and call us.

What you get

A plain-English explanation of what failed, what it will take to fix, and what it will cost — in writing, before we touch anything. If the fix is something simple you can handle yourself, we will tell you that too.