Engine Controls - O2 Sensor DTC Testing Corrections

Classification:
EC99-003

Reference:
NTB99-019

Date:
April 15, 1999

SERVICE MANUAL PROCEDURE CHANGE FOR REAR OXYGEN SENSOR DTC(S) P0137, P0138, P0139, P0140, P0141 AND THREE-WAY CATALYST DTC P0420

APPLIED VEHICLES:
All 1998-later Maxima (A32)
All 1998-later Quest (V40)
All 1998-later 240SX (S14)
All 1998-later Sentra/200SX (B14) - GA16DE
All 1998-later Pathfinder (R50)
All 1998-later Altima (L30)

SERVICE INFORMATION

The service manual procedures for DTC confirmation of the rear oxygen sensor DTCs and the three-way catalyst DTC have changed. The new procedures require the vehicle be driven at a speed of more than 43 MPH (70 KPH) for two consecutive minutes before performing the DTC Confirmation Procedures and/or the Component Inspection for the listed DTCs. The reason for this change is due to an increase in time (after the vehicle is started) before the rear heated oxygen sensor is energized by the ECM. This time delay requires the vehicle be driven to ensure the rear heated oxygen sensor is energized and operational.

When using the service manual to perform the Diagnosis Trouble Code Confirmation Procedure and/or Component Inspection on an applied vehicle, it will be necessary to include the additional steps listed in the charts in this bulletin.

IMPORTANT:
^ Failure to drive the vehicle as specified before performing the diagnosis will result in mis-diagnosis.

^ Do not turn the engine off after driving the vehicle as specified. If the vehicle's engine is turned off after the vehicle is driven and before the diagnosis procedures are performed, the vehicle must be driven (as specified) again.

SERVICE PROCEDURE





Refer to the charts when performing the Diagnosis Trouble Code Confirmation Procedure and/or Component Inspection for the DTCs and vehicles listed.

NOTE:
Add a note on the service manual pages listed below that instructs the user (of the service manual) to refer to NTB99-019 for additional information.

Trouble Diagnosis for P0140





On the service manual page indicated in the chart: (1) replace step two with this statement:

"Start the engine and drive the vehicle at a speed of more than 43 MPH (70 KPH) for 2 consecutive minutes." (2) replace step three with the specifications listed in the chart.