Q: The Check Engine Light is on but the scanner shows no codes.

asked by on

Check engine light turned on shortly after mechanic checked alternaator and battery voltage with his tool. The mechanic told me the battery (not the IMA battery) is dead after checking the voltage. But I bought a new scanner and it shows no codes and says MIL status is off, although the check engine light is on.

My car has 140000 miles.
My car has an automatic transmission.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. The Check Engine Light is on but the scanner shows no codes.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Reverse Gear Issue

Harsh gear engagement is due to an internal transmission fault. Among the possible scenarios are internal hydraulic leaks, or out of range line pressure. Hydraulic force is what effects shifting and if the "force" is delayed, too high, or applied...

Q: Q: Code p0421

Are there other codes set? This code, by itself, P0421 indicates that the engine management system detected the catalytic converter is performing below expected standards. This means the engine is sending contaminants (unburned fuel, oil fumes, etc.) down the exhaust,...

Q: 2008 Mazda 5 has codes P0661 and P0720

Input from the vehicle speed sensor (VSS) is used by the transmission control module (TCM) to calculate shift points, torque converter operation and other transmission functions. Code P0720 stands for Vehicle Speed Sensor circuit malfunction. Typically, this code indicates a...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...