EC-1004Revision: May 2004

[QG18DE (SULEV)]DTC P1147 HO2S2

2003 Sentra

Specification data are reference values and are measured between each terminal and ground.CAUTION:Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

Diagnostic Procedure UBS006A4

1. RETIGHTEN GROUND SCREWS

1. Turn ignition switch “OFF”.2. Loosen and retighten engine ground screws.

>> GO TO 2.

TERMI-NAL NO.

WIRE COLOR

ITEM CONDITION DATA (DC Voltage)

74 R/L Heated oxygen sensor 2

[Engine is running]

● Warm-up condition

● Revving engine from idle up to 3,000 rpm quickly after the following conditions are met.

● Keeping the engine speed between 3,500 and 4,000 rpm for one minute and at idle for one minute under no load.

0 - Approximately 1.0V

78 BSensor ground(Heated oxygen sensor)

[Engine is running]

● Warm-up condition

● Idle speed

Approximately 0V

BBIA0155E

DTC P1147 HO2S2

EC-1005

[QG18DE (SULEV)]

C

D

E

F

G

H

I

J

K

L

M

A

EC

Revision: May 2004 2003 Sentra

2. CLEAR THE SELF-LEARNING DATA

With CONSULT-II1. Start engine and warm it up to normal operating temperature.2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode

with CONSULT-II.3. Clear the self-learning control coefficient by touching “CLEAR”.4. Run engine for at least 10 minutes at idle speed.

Is the 1st trip DTC P0171 detected?Is it difficult to start engine?

Without CONSULT-II1. Start engine and warm it up to normal operating temperature.2. Turn ignition switch “OFF”.3. Disconnect mass air flow sensor harness connector, and restart

and run engine for at least 5 seconds at idle speed.4. Stop engine and reconnect mass air flow sensor harness con-

nector.5. Make sure that DTC P0102 is displayed.6. Erase the DTC memory. Refer to EC-651, "HOW TO ERASE

EMISSION-RELATED DIAGNOSTIC INFORMATION" .7. Make sure that DTC P0000 is displayed.8. Run engine for at least 10 minutes at idle speed.

Is the 1st trip DTC P0171 detected?Is it difficult to start engine?

Yes or NoYes >> Perform trouble diagnosis for DTC P0171. Refer to EC-795 .No >> GO TO 3.

3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch “OFF”.2. Disconnect heated oxygen sensor 2 harness connector.3. Disconnect ECM harness connector.4. Check harness continuity between ECM terminal 78 and HO2S2

terminal 4.Refer to Wiring Diagram.

5. Also check harness for short to ground and short to power.OK or NGOK >> GO TO 4.NG >> Repair open circuit or short to ground or short to power

in harness or connectors.

SEF215Z

BBIA0150E

Continuity should exist.

BBIA0175E

EC-1006Revision: May 2004

[QG18DE (SULEV)]DTC P1147 HO2S2

2003 Sentra

4. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check harness continuity between ECM terminal 74 and HO2S2 terminal 1.Refer to Wiring Diagram.

2. Check harness continuity between ECM terminal 74 or HO2S2 terminal 1 and ground.Refer to Wiring Diagram.

3. Also check harness for short to power.OK or NGOK >> GO TO 5.NG >> Repair open circuit or short to ground or short to power in harness or connectors.

5. CHECK HEATED OXYGEN SENSOR 2

Refer to EC-1006, "Component Inspection" .OK or NGOK >> GO TO 6.NG >> Replace heated oxygen sensor 2.

6. CHECK INTERMITTENT INCIDENT

Refer to EC-720, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .

>> INSPECTION END

Component Inspection UBS006A5

HEATED OXYGEN SENSOR 2 With CONSULT-II

1. Start engine and warm it up to the normal operating temperature.2. Turn ignition switch “OFF” and wait at least 10 seconds.3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no

load.4. Let engine idle one minute.5. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select

“HO2S2 (B1)” as the monitor item with CONSULT-II.

Continuity should exist.

Continuity should not exist.

SEF519Z

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