Inspection Procedure

Total OBD & ECU Auto Diagnostics

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Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.


Intelligent tester only:

Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE

TEST. The A/F CONTROL function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated

Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the A/F CONTROL operation using the intelligent tester.

(a)Connect the intelligent tester to the DLC3.

(b)Start the engine and turn the tester on.

(c)Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.

(d)On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/ F CONTROL.

(e)Perform the A/F CONTROL operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).

(f) Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2) displayed on the tester.


• The A/F CONTROL operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.

• The sensors react in accordance with increases and decreases in the fuel injection volume.

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