Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Checking Mass Air Flow Sensor Signal

Checking Mass Air Flow Sensor Signal
- Ignition ON.
- Go into scrolling values.
- Operate starter motor.
- Read OFF load signal.
- The value should be at approx. 0.4 - 0.6 Volts.

If reading is OK:
^ Proceed to: Checking Engine Coolant Temperature Sensor Signal.

If reading is incorrect:
^ Fault-trace mass air flow sensor.
^ Proceed to: Testing By Trouble Code - Code EFI-121 Mass Air Flow Sensor Signal.