Check Any Other Dtcs Output In Addition To Dtc P

(a) Connect the intelligent tester to the DLC3.

(b) Turn the ignition switch to the ON position and turn the tester on.

(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

Result

Display (DTC Output)

Proceed to

P0420

A

P0420 and other DTCs

If any DTCs other than P0420 are output, troubleshoot those DTCs first.

GO TO DTC CHART

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (A/F CONTROL)

(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 B1 S1 and O2S B1 S2) displayed on the tester. Result:

A/F sensor reacts in accordance with increases and decreases in fuel injection volume: +25 % = Rich output:

Less than 3.0 V -12.5 % = Lean output: More than 3.35 V NOTICE:

The A/F sensor has an output delay of a few seconds and the HO2 sensor has a maximum output delay of approximately 20 seconds.

Case

A/F Sensor (Sensor 1) Output Voltage

HO2 Sensor (Sensor 2) Output Voltage

Main Suspected Trouble Areas

1

Injection Volume +25 % -12.5 %

Injection Volume +25 % -12.5 %

• Exhaust gas leakage

Output Voltage More than 3.35 V Less than 3.0 V

"UTS?

Output Voltage More than 0.5 V Less than 0.4 V

2

Injection Volume +25 % -12.5 %

♦ _TLr

Injection Volume +25 % -12.5 %

♦ _TLT

• A/F sensor circuit

Output Voltage Almost no reaction

-NG

Output Voltage More than 0.5 V Less than 0.4 V

-TUBk

Case

A/F Sensor (Sensor 1) Output Voltage

HO2 Sensor (Sensor 2) Output Voltage

Main Suspected Trouble Areas

3

Injection Volume +25 % -12.5 %

Injection Volume +25 % -12.5 %

• HO2 sensor heater

• HO2 sensor circuit

Output Voltage More than 3.35 V Less than 3.0 V

-LXTÏ

Output Voltage Almost no reaction

-NG

4

Injection volume +25 % -12.5 %

♦ _TLr

Injection Volume +25 % -12.5 %

♦ _TLT

Extremely rich or lean actual air-fuel ratio

• Fuel pressure

• Gas leakage from exhaust system

Output Voltage Almost no reaction

-NG

Output Voltage Almost no reaction

-NG

Following the A/F CONTROL procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.

To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1 S1 and O2S B1 S2; then press the YES button and then the ENTER button followed by the F4 button.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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