DTC Description

DTC DETECTION LOGIC

To judge malfunctions, this diagnosis measures response time of the A/F signal computed by ECM from the A/F sensor 1 signal. The time is compensated by engine operating (speed and load), fuel feedback control constant, and the A/F sensor 1 temperature index. Judgment is based on whether the compensated time (the A/F signal cycling time index) is inordinately long or not.

DTC		M.U.T.-III SE screen terms (Trouble diagnosis content)	DTC detection condition
P014C	00	A/F SENSOR1 (B1) (O2 sensor slow response - rich to lean bank 1 sensor 1)	Diagnosis condition	—
			Signal (terminal)	A/F sensor 1 signal
			Threshold	The response time of a A/F sensor 1 signal delays more than the specified time computed by ECM
			Diagnosis delay time	—

POSSIBLE CAUSE

Harness or connectors (The A/F sensor 1 circuit is open or shorted.)
A/F sensor 1

FAIL-SAFE

Not applicable

DTC Confirmation Procedure

1.PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.

Turn ignition switch OFF and wait at least 10 seconds.
Turn ignition switch ON.
Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

Do you have M.U.T.-III SE?

2.PERFORM DTC CONFIRMATION PROCEDURE-1

With M.U.T.-III SE

Start engine and warm it up to normal operating temperature.
Turn ignition switch OFF and wait at least 10 seconds.
Turn ignition switch ON.
Turn ignition switch OFF and wait at least 10 seconds.
Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute under no load.
Let engine idle for 1 minute.
Increase the engine speed up to about 3,600 rpm and keep it for 10 seconds.
Fully release accelerator pedal and then let engine idle for about 1 minute.
Check the items status of “DATA MONITOR” as follows.
note If “Active DTC” changed to “ABSNT”, refer to Component Function Check.
Data monitor item Status
A/F SEN1 DIAG3 (B1) PRSNT

Data monitor item	Status
A/F SEN1 DIAG3 (B1)	PRSNT

Is “Active DTC” displayed on M.U.T.-III SE screen?

3.PERFORM DTC CONFIRMATION PROCEDURE-2

With M.U.T.-III SE

Perform DTC confirmation procedure-1 again.

Is “Active DTC” displayed on M.U.T.-III SE screen?

Refer to Component Function Check

4.PERFORM DTC CONFIRMATION PROCEDURE-2

With M.U.T.-III SE

Wait for about 20 seconds at idle.
Check the items status of “DATA MONITOR” as follows.
note If “CMPLT” changed to “INCMP”, refer to Component Function Check.
Data monitor item Status
A/F SEN1 DIAG1 (B1) CMPLT
A/F SEN1 DIAG2 (B1)

Data monitor item	Status
A/F SEN1 DIAG1 (B1)	CMPLT
A/F SEN1 DIAG2 (B1)

Is “CMPLT” displayed on M.U.T.-III SE screen?

Refer to Component Function Check

5.PERFORM SELF-DIAGNOSIS

With M.U.T.-III SE

Check the “SELF-DIAG RESULT”.

Is any DTC detected?

Proceed to DTC Diagnosis Procedure

INSPECTION END

6.CHECK AIR-FUEL RATIO SELF-LEARNING VALUE

With GST

Start engine and warm it up to normal operating temperature.
Select Service $01 with GST.
Calculate the total value of “Short term fuel trim” and “Long term fuel trim” indications.

Is the total percentage within ±15%?

7.DETECT MALFUNCTIONING PART

Check the following.

Intake air leaks
Exhaust gas leaks
Incorrect fuel pressure
Lack of fuel
Fuel injector
Incorrect PCV hose connection
PCV valve
Mass air flow sensor

: Repair or replace malfunctioning part.

8.PERFORM DTC CONFIRMATION PROCEDURE

Turn ignition switch OFF and wait at least 10 seconds.
Turn ignition switch ON.
Turn ignition switch OFF and wait at least 10 seconds.
Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
Let engine idle for 1 minute.
Increase the engine speed up to about 3,600 rpm and keep it for 10 seconds.
Fully release accelerator pedal and then let engine idle for about 1 minute.
Check 1st trip DTC.

Is 1st trip DTC detected?

Proceed to DTC Diagnosis Procedure

-1To check malfunction symptom before repair: Refer to Intermittent IncidentIntermittent Incident

-2Confirmation after repair: INSPECTION END