Infiniti: Removal of a Seized Exhaust Sensor

Infiniti: Removal of a Seized Exhaust Sensor

If an exhaust sensor is seized in the exhaust manifold/catalyst/front tube, perform the service procedure to remove the sensor and prevent unnecessary replacement of the exhaust manifold/catalyst/front tube. In most cases, this ­procedure is successful because the threads of the ­exhaust sensors are made of a softer material than the part they thread into on the exhaust manifold/catalyst/front tube.

This procedure can be performed in two ways:

Method 1

If the sensor can be easily accessed:
• The procedure can be performed on the ­vehicle.
• The exhaust manifold/catalyst/front tube will not have to be removed.

Infiniti exhaust sensor
Fig. 1

Method 2

If the sensor cannot be easily accessed:
• The exhaust manifold/catalyst/front tube must be removed from the vehicle.
• The procedure will be ­performed with the part clamped in a vice.


• The following service ­procedure is for Method 2. Method 1 is the same as Method 2 except that it’s ­performed on the vehicle.
• You’ll need Nissan Rust Penetrant or ­equivalent.
• When removing a seized exhaust sensor with a specialty socket, which contains a slit for the wiring harness, it may spread open and strip the sensor. To avoid this, cut the harness from the sensor and use a box end wrench or 6-point deep well socket. (See Fig. 1)

Service Procedure:

1. Clamp the exhaust manifold/catalyst/front tube in a vice.

2. Spray the sensor with the rust penetrant for 2 to 3 seconds. The spray needs to be directed at the base of the ­sensor to ensure it penetrates into the threads (See Fig. 2).

Infiniti exhaust sensor
Fig. 2

3. Loosen the sensor approximately 10º (See Fig. 3).

Infiniti exhaust sensor
Fig. 3

4. Spray with rust penetrant again for 2 to 3 seconds.

5. Tighten the sensor 10º, then loosen the sensor 10º. Repeat this motion several times until the sensor begins to turn more easily (See Fig. 4).

Infiniti exhaust sensor
Fig. 4

6. Continue the tight-ening/loosening motion while gradually unscrewing the sensor. Stop when the sensor will not unscrew any farther.

7. Spray with rust penetrant again for 2 to 3 seconds (See Fig. 5).

Infiniti exhaust sensor
Fig 5.

8. Repeat steps 6 and 7 until the sensor is removed.

9. Use compressed air to remove any metal debris from inside the boss threads (See Fig. 6). Caution: Do not perform this step if the Method #1 procedure is being done on the vehicle. Doing so may cause metal debris to enter the engine cylinders.

Infiniti exhaust sensor
Fig. 6

10. If metal debris remains trapped in the boss threads, use a spiral nylon brush to remove it (See Fig. 7).

Infiniti exhaust sensor
Fig. 7

11. Spray the boss threads with rust penetrant for 2 to 3 seconds.

12. Run a thread chaser through the boss to clean the threads (See Fig. 8).

Infiniti exhaust sensor
Fig. 8

13. Use compressed air to remove any remaining debris (See Fig. 9). Caution: Do not perform this step if the Method #1 procedure is being done on the vehicle.

Infiniti exhaust sensor
Fig. 9

14. If metal debris remains trapped in the boss threads, use a spiral nylon brush to remove it.

15. Tilt the manifold/catal-yst/front tube so that the metal debris falls out of the part.

16. Apply compressed air through the boss to blow out any remaining debris. Caution: Do not perform this step if the Method #1 procedure is being done on the vehicle.

17. Install the new sensor as described in the applicable electronic service manual (ESM).

Courtesy of ALLDATA.

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