Perform Active Test Using Intelligent Tester Af Control

Total OBD & ECU Auto Diagnostics

TOAD Auto Diagnostics

Get Instant Access

Standard Voltage

(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 in an idling condition (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 B1S1 and O2S B1S2) displayed on the tester.

HINT:

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

• Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Standard Voltage

Tester Display (Sensor)

Injection Volumes

Status

Voltages

AFS B1S1 (A/F)

+25 %

Rich

Less than 3.0

AFS B1S1 (A/F)

-12.5 %

Lean

More than 3.35

O2S B1S2 (HO2)

+25 %

Rich

More than 0.5

O2S B1S2 (HO2)

-12.5 %

Lean

Less than 0.4

Result

Status AFS B1S1

A/F and HO2 Sensors Condition

Misfires

Main Suspected Trouble Areas

Proceed To

Lean/Rich

Lean/Rich

Normal

-

• Three-Way Catalytic Converter (TWC)

• Gas leakage from exhaust system

A

Lean

Lean/Rich

A/F sensor malfunction

-

• A/F sensor

B

Status AFS B1S1

A/F and HO2 Sensors Condition

Misfires

Main Suspected Trouble Areas

Proceed To

Rich

Lean/Rich

A/F sensor malfunction

-

• A/F sensor

B

Lean/Rich

Lean

HO2 sensor malfunction

• Gas leakage from exhaust system

C

Lean/Rich

Rich

HO2 sensor malfunction

• Gas leakage from exhaust system

C

Lean

Lean

Actual air-fuel ratio lean

May occur

• Extremely rich or lean actual air-fuel ratio

• Gas leakage from exhaust system

A

Rich

Rich

Actual air-fuel ratio rich

-

• Extremely rich or lean actual air-fuel ratio

• Gas leakage from exhaust system

A

Lean: During A/F CONTROL, the A/F sensor output voltage (AFS) is consistently more than 3.35 V, and the HO2 sensor output voltage (O2S) is consistently less than 0.4 V. Rich: During A/F CONTROL, the AFS is consistently less than 3.0 V, and the O2S is consistently more than 0.5 V. Lean/Rich: During A/F CONTROL of the ACTIVE TEST, the output voltage of the HO2 sensor alternates correctly.

Was this article helpful?

0 0
Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Post a comment