2001 Nissan Sentra Misfiring and has OBD2 code PO154

Tiny
SUPERMOTON1
  • MEMBER
  • 2001 NISSAN SENTRA
Engine Performance problem
2001 Nissan Sentra 4 cyl Front Wheel Drive Automatic 70k +? Miles

Hello and thanks for any help in advance! I have a single mom friend in my church who's car has a noticeable misfire, check engine light is on. I borrowed a scanner and found it to have 1 code. P0154. I looked at the freeze frame data and saved all of it. Something that stood out to me(and not knowing much about it) that the values at the ST TRIM B1 (%) 0.0 and the ST TRIM B2 (%) -10.2.
Could you steer me in the right dirrection to repair this condition? I think she had someone maybe replace coil packs with some from a wrecking yard but did not repair problem. I have not purchased a repair manual yet. But will if needed. Thanks again for any help you can offer. Kevin.
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Monday, April 19th, 2010 AT 12:27 PM

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Tiny
BMRFIXIT
  • EXPERT
DTC P0154: LEFT BANK FRONT HEATED OXYGEN SENSOR
CAUTION:DO NOT reuse any HO2S that has been dropped from a height of 20" (.5 m) or more onto a hard surface, such as concrete.

NOTE:Right bank is the bank that includes cylinders No. 1 and 4. Left bank is the bank that includes cylinders No. 2 and 3.

NOTE:Before performing diagnostic procedure, follow testing procedure.
DTC Confirmation Test
Malfunction is detected when HO2S voltage is too high. Possible causes are:
HO2S circuit open or shorted.
Defective HO2S.
To set DTC, start engine and warm to normal operating temperature.
Turn ignition off and wait at least 10 seconds.
Start engine and let it idle for 2 minutes.
Turn ignition off and wait at least 10 seconds.
Start engine and let it idle for 2 minutes. Select MODE 3 with scan tool.
If DTC is detected, go to PROCEDURE.
Procedure
Loosen and retighten front HO2S to 30-44 ft. Lbs. (40-60 N.M).
Turn ignition off.
Disconnect ECM harness connector.
Disconnect appropriate front HO2S harness connector
Check continuity of White wire between right front HO2S harness connector terminal No. 2 and ECM harness connector terminal No. 62, or Green wire between left front HO2S harness connector terminal No. 2 and ECM harness connector terminal No. 94.
Also check circuit for short to ground and short to voltage.
Repair circuit as necessary and retest system. If circuit is okay, go to next step.
Inspect HO2S harness connector for water.
If water exists, repair or replace connector as necessary and retest system. If connector is okay, go to next step.
CAUTION:DO NOT use ECM ground terminals when measuring voltage.

Reconnect all harness connectors. Start engine and warm to normal operating temperature. Measure voltage between ground and ECM terminal No. 62 (right front HO2S) or No. 94 (left front HO2S) by backprobing. See Fig. 3 and Fig. 4. Increase engine speed to 2000 RPM. The following conditions should exist:
Voltage cycles from 0-0.3 volt to 0.6-1.0 volt more than 5 times within 10 seconds.
Maximum voltage is more than.6 volt at least once.
Minimum voltage is less than.3 volt at least once.
Voltage never exceeds one volt.
If operation is as specified, go to next step. If operation is not as specified, replace appropriate front HO2S and retest system.
No problem is indicated at this time. Problem may be intermittent
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Monday, April 19th, 2010 AT 7:59 PM

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