Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSINFINITI2002G20 L4-2.0L (SR20DE)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSOXYGEN SENSORTECHNICAL SERVICE BULLETINSCUSTOMER INTERESTO2 SENSOR - MIL ON/DTC P0138/P0139/P0140 SET
2002 Infiniti G20 L4-2.0L (SR20DE)
O2 Sensor - MIL ON/DTC P0138/P0139/P0140 Set
2002 Infiniti G20 L4-2.0L (SR20DE)SECTION O2 Sensor - MIL ON/DTC P0138/P0139/P0140 Set
Classification:
E002-011
Reference:
ITB02-022
Date:
April 15, 2002
2000-2002 G20 MIL "ON" REAR 02 SENSOR DTC P0138/P0139/P0140
APPLIED VEHICLES:
2000-2002 G20 (P11)
SERVICE INFORMATION
If a 2000 to 2002 G20 has a MIL "On" and any of the following DTCs stored in the ECM:
^ P0138 Heated Oxygen Sensor 2 (Rear) (Bank 1) (Max. Voltage Monitoring)
^ P0139 Heated Oxygen Sensor 2 (Rear) (Bank 1) (Response Monitoring)
^ P0140 Heated Oxygen Sensor 2 (Rear) (Bank 1) (High Voltage)
Start with the Service Procedure to find out if the bulletin applies to this vehicle. If it does apply, complete the Service Procedure to repair the incident, if it should occur.
SERVICE PROCEDURE
You will be performing the following, as required:
^ Determine the DTC Stored in ECM from the CONSULT-II Self-diagnosis results.
^ ECM Part Number Check to determine if this bulletin applies.
^ ECM Reprogramming (required if the ECM P/N in the vehicle matches one of those listed under "Current ECM P/N" in Chart A).
^ Replacing the Rear Oxygen Sensor (required if ECM Reprogramming is needed).
Determine the DTC Stored in ECM:
1. Determine which DTC code is stored in the vehicle's ECM by performing CONSULT-II Self-Diagnosis.

2. Print out the Self-Diagnosis results for use in ECM Part Number Check, below. See Figure 1 for an example of the CONSULT-II Self-Diagnosis printout.
ECM Part Number Check
1. Compare the vehicle's current ECM P/N (from your CONSULT-II Self Diagnosis printout) to those shown under Current ECM P/N in Chart A, below:

Chart A - Current ECM P/N's:
A. If the ECM P/N in the vehicle matches one of those listed under "Current ECM P/N" in Chart A (above):
^ Look in the "Vehicle" Column in Chart A (above) and determine the vehicle "configuration" (i.e. 2002 M/T). Make a note of the vehicle configuration and perform ECM Reprogramming, below.
B. If the ECM P/N in the vehicle does not match one of those listed under "Current ECM P/N" in Chart A (above):
^ This bulletin does not apply. Use the appropriate Electronic Service Manual (ESM) to further diagnose and repair the incident.
ECM Reprogramming
1. Perform ECM Reprogramming to install the latest available ECM data.
^ If you are unfamiliar with ECM Reprogramming, click here to link to the "ECM Reprogramming For Infiniti Vehicles" general procedure or refer to Attachment A in the print copy of this bulletin.

For those familiar with ECM Reprogramming, perform the following:
A) Select model and model year for the applied vehicle (i.e. G20, 2002).
B) Locate the vehicle configuration you made note of in step 1A (i.e. M/T) from those listed in the upper right ECM data description window.
C) Make a note of the "To" number listed in the "ECM Reprogramming Data" Summary screen.
NOTE:
The "To" number will read: 23710-XXXXX.
D) Press "Continue" and follow directions to perform data download from ASIST to CONSULT-II.
E) When reprogramming from CONSULT-II, select the "To" number that you made note of in step C, above.
2. Go to and perform Replacing the Rear Oxygen Sensor (below).
Replacing the Rear Oxygen Sensor
1. Replace the incident bank rear oxygen sensor (see the PARTS INFORMATION section for information). Refer to the EC Section of the appropriate Service Manual for part replacement information.
2. Use CONSULT-II to do the following:
^ Confirm DTC P0138, P0139, or P0140 is repaired.
^ Erase the DTC code.

PARTS INFORMATION
CLAIMS INFORMATION

Submit a Primary Failed Part (PP) line claim using the claims coding shown.
E002-011
Reference:
ITB02-022
Date:
April 15, 2002
2000-2002 G20 MIL "ON" REAR 02 SENSOR DTC P0138/P0139/P0140
APPLIED VEHICLES:
2000-2002 G20 (P11)
SERVICE INFORMATION
If a 2000 to 2002 G20 has a MIL "On" and any of the following DTCs stored in the ECM:
^ P0138 Heated Oxygen Sensor 2 (Rear) (Bank 1) (Max. Voltage Monitoring)
^ P0139 Heated Oxygen Sensor 2 (Rear) (Bank 1) (Response Monitoring)
^ P0140 Heated Oxygen Sensor 2 (Rear) (Bank 1) (High Voltage)
Start with the Service Procedure to find out if the bulletin applies to this vehicle. If it does apply, complete the Service Procedure to repair the incident, if it should occur.
SERVICE PROCEDURE
You will be performing the following, as required:
^ Determine the DTC Stored in ECM from the CONSULT-II Self-diagnosis results.
^ ECM Part Number Check to determine if this bulletin applies.
^ ECM Reprogramming (required if the ECM P/N in the vehicle matches one of those listed under "Current ECM P/N" in Chart A).
^ Replacing the Rear Oxygen Sensor (required if ECM Reprogramming is needed).
Determine the DTC Stored in ECM:
1. Determine which DTC code is stored in the vehicle's ECM by performing CONSULT-II Self-Diagnosis.
2. Print out the Self-Diagnosis results for use in ECM Part Number Check, below. See Figure 1 for an example of the CONSULT-II Self-Diagnosis printout.
ECM Part Number Check
1. Compare the vehicle's current ECM P/N (from your CONSULT-II Self Diagnosis printout) to those shown under Current ECM P/N in Chart A, below:
Chart A - Current ECM P/N's:
A. If the ECM P/N in the vehicle matches one of those listed under "Current ECM P/N" in Chart A (above):
^ Look in the "Vehicle" Column in Chart A (above) and determine the vehicle "configuration" (i.e. 2002 M/T). Make a note of the vehicle configuration and perform ECM Reprogramming, below.
B. If the ECM P/N in the vehicle does not match one of those listed under "Current ECM P/N" in Chart A (above):
^ This bulletin does not apply. Use the appropriate Electronic Service Manual (ESM) to further diagnose and repair the incident.
ECM Reprogramming
1. Perform ECM Reprogramming to install the latest available ECM data.
^ If you are unfamiliar with ECM Reprogramming, click here to link to the "ECM Reprogramming For Infiniti Vehicles" general procedure or refer to Attachment A in the print copy of this bulletin.
For those familiar with ECM Reprogramming, perform the following:
A) Select model and model year for the applied vehicle (i.e. G20, 2002).
B) Locate the vehicle configuration you made note of in step 1A (i.e. M/T) from those listed in the upper right ECM data description window.
C) Make a note of the "To" number listed in the "ECM Reprogramming Data" Summary screen.
NOTE:
The "To" number will read: 23710-XXXXX.
D) Press "Continue" and follow directions to perform data download from ASIST to CONSULT-II.
E) When reprogramming from CONSULT-II, select the "To" number that you made note of in step C, above.
2. Go to and perform Replacing the Rear Oxygen Sensor (below).
Replacing the Rear Oxygen Sensor
1. Replace the incident bank rear oxygen sensor (see the PARTS INFORMATION section for information). Refer to the EC Section of the appropriate Service Manual for part replacement information.
2. Use CONSULT-II to do the following:
^ Confirm DTC P0138, P0139, or P0140 is repaired.
^ Erase the DTC code.
PARTS INFORMATION
CLAIMS INFORMATION
Submit a Primary Failed Part (PP) line claim using the claims coding shown.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.