Operation CHARM: Car repair manuals for everyone.
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 logical successor to CHARM, I recommend you try it!

Link: lemon-manuals.la

HO2S 1

Scan Tool Range 0 to 1132 mV. Represents the fuel control exhaust oxygen sensor output voltage. Should fluctuate constantly within a range between 10 mV (lean exhaust) and 1000 mV (rich exhaust) while operating in Closed Loop.

Scan Tool Displays NOT READY or READY. Indicates the status of the fuel control exhaust oxygen sensor. The scan tool will indicate that the exhaust oxygen sensors are ready when the PCM detects a fluctuating HO2S voltage sufficient to allow closed loop operation. This will not occur unless the exhaust oxygen sensors are warmed up.