Parts Catalog Accessories Catalog Tech Info Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
8-Cylinder Engine Oxygen Sensor Replacement
 
Bookmark and Share

Pelican Technical Article:

8-Cylinder Engine Oxygen Sensor Replacement

Nick Czerula

Time:

3 hours3 hrs

Tab:

$300

Talent:

****

Tools:

Oxygen sensor socket, 22mm wrench, flathead screwdriver, floor jack, two jack stands, two wheel chocks, safety glasses, torque wrench, anti-seize, BMW scan tool

Applicable Models:

BMW X5 (2000-06)

Parts Required:

Oxygen sensors, anti-seize paste

Hot Tip:

Work with a cool exhaust

Performance Gain:

Remedy fault codes and maintain proper running engine

Complementary Modification:

Replace in pairs

Oxygen sensors monitor the exhaust stream, comparing the oxygen content in it to the oxygen content ambient air. When oxygen content is low, sensor voltage is high. When oxygen content is high, sensor voltage is low. The voltage created by the sensor is sent to the DME (engine control module) to help maintain a proper fuel mixture. The mixture preparation is used to keep the catalytic converters running at peak efficiency. The oxygen sensors used in E53 models covered in this article have four wires. Two of the wires are for oxygen sensor heating and two for the signal. The heater is used to get the sensor online faster. Previously, exhaust heat was used. One wire supplied a ground to the sensor for the signal, and the other is for the sensor signal.

Oxygen sensors should be replaced every 100,000 miles. In a perfect world that would be it. Wait until a specified mileage and replace the sensor. However, these sensors fail prematurely, set oxygen sensor fault codes and reduce fuel economy. In this article, I will show you how to identify the location of all four oxygen sensors and how to replace them. You will need an oxygen sensor socket to remove the sensors and remember to always work with a cool exhaust. Oxygen sensors are fragile. Do not drop them, as damage may occur. Also, keep the sensor tip clean when reinstalling.

Oxygen sensors are laid out in banks, which refer to cylinders and in sensor numbers referring to before or after the catalytic converter. Bank1 or B1 refers to cylinders 1-4. Bank 2 or B2 refers to cylinders 5-8. Sensor 1 or S1 refers to the sensor before the catalytic converter. Sensor 2 or S2 refers to the sensor after the catalytic converter. Cylinder 1 is on the right side of the engine.

Remember your car may have been serviced before and had parts replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.

Our vehicle may vary slightly from yours as models do change and evolve, as they grow older. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Jack up your vehicle and remove the lower splash shields. See the corresponding tech articles.

Replacing sensors before catalytic converter: 
Replacing sensors before catalytic converter: This photo shows the front oxygen sensors (blue arrows) viewed from below.
Figure 1

Replacing sensors before catalytic converter: This photo shows the front oxygen sensors (blue arrows) viewed from below. Bank 1 is on the right and bank 2 is on the left. I will show you how to replace the front right side. The front left side is similar.

Replacing sensors before catalytic converter: Follow the oxygen sensor wiring harness to the side of the transmission (blue arrows).
Figure 2

Replacing sensors before catalytic converter: Follow the oxygen sensor wiring harness to the side of the transmission (blue arrows).

Replacing sensors before catalytic converter: Label or mark the wiring harness to aide during reinstallation.
Figure 3

Replacing sensors before catalytic converter: Label or mark the wiring harness to aide during reinstallation. I suggest replacing one sensor at a time so you do not mix them up with their appropriate connectors. If needed, pull the wiring harness out of the mount. Then disconnect the electrical connector by pulling it straight apart.

Replacing sensors before catalytic converter: Using an oxygen sensor socket (blue arrow), loosen the oxygen sensor connection to the front pipe.
Figure 4

Replacing sensors before catalytic converter: Using an oxygen sensor socket (blue arrow), loosen the oxygen sensor connection to the front pipe.

Replacing sensors before catalytic converter: Unscrew the oxygen sensor from the front pipe.
Figure 5

Replacing sensors before catalytic converter: Unscrew the oxygen sensor from the front pipe. Detach the wiring harness from the mounting points and remove the sensor from the vehicle.

Replacing sensors before catalytic converter: This photo shows the front right side oxygen sensor removed.
Figure 6

Replacing sensors before catalytic converter: This photo shows the front right side oxygen sensor removed. Lightly coat the new oxygen sensor thread with anti-seize compound. Install the new oxygen sensor and tighten it to 50Nm (37 ft-lb). Then reroute the wiring harness and connect the electrical connector. Repeat if replacing both sensors. Then reassemble the engine covers and clear any engine fault codes using a BMW scan tool.

Replacing sensors after catalytic converter: 
Replacing sensors after catalytic converter: The oxygen sensor is located in the exhaust, behind the catalytic converter.
Figure 7

Replacing sensors after catalytic converter: The oxygen sensor is located in the exhaust, behind the catalytic converter. Working behind the catalytic converter on the right side, remove the vibration damper. Start by removing the lower nut. Counterhold the 13mm bolt (red arrow) while removing the 13mm nut (blue arrow).

Replacing sensors after catalytic converter: Next, remove the upper nut.
Figure 8

Replacing sensors after catalytic converter: Next, remove the upper nut. Counterhold the 13mm bolt (red arrow) while removing the 13mm nut (blue arrow).

Replacing sensor after catalytic converter: Once the nuts and bolts are removed, remove the damper from the exhaust.
Figure 9

Replacing sensor after catalytic converter: Once the nuts and bolts are removed, remove the damper from the exhaust.

Replacing sensor after catalytic converter: Next, remove the damper heat shield.
Figure 10

Replacing sensor after catalytic converter: Next, remove the damper heat shield.

Replacing sensor after catalytic converter: To remove the sensor, start by disconnecting the electrical connector (blue arrow).
Figure 11

Replacing sensor after catalytic converter: To remove the sensor, start by disconnecting the electrical connector (blue arrow). First, detach the wiring harness from the metal clips (red arrows).

Replacing sensor after catalytic converter: Pull the electrical connector out of the mount.
Figure 12

Replacing sensor after catalytic converter: Pull the electrical connector out of the mount. Then disconnect the electrical connector by pulling it straight apart.

Replacing sensor after catalytic converter: Using an oxygen sensor socket (red arrow), loosen the oxygen sensor connection to the exhaust pipe.
Figure 13

Replacing sensor after catalytic converter: Using an oxygen sensor socket (red arrow), loosen the oxygen sensor connection to the exhaust pipe.

Replacing sensor after catalytic converter: Unscrew the oxygen sensor from the exhaust pipe and remove it.
Figure 14

Replacing sensor after catalytic converter: Unscrew the oxygen sensor from the exhaust pipe and remove it.

Replacing sensors before catalytic converter: This photo shows the rear oxygen sensor removed.
Figure 15

Replacing sensors after catalytic converter: This photo shows the rear oxygen sensor removed. Lightly coat the new oxygen sensor thread with anti-seize compound. Install the new oxygen sensor and torque it to 50Nm (37 ft-lb). Then reroute the wiring harness and connect the electrical connector. Then reassemble the engine covers and clear any engine fault codes using a BMW scan tool.

Bookmark and Share
Comments and Suggestions:
Frenchy Comments: When one sensor bad still will the check engine light still come on the BMW 325xi 2002.I changed 3 found out from you it have 4.
September 7, 2016
  Followup from the Pelican Staff: If only one sensor is bad, the light will come on with a code for that sensor. - Nick at Pelican Parts  
ali Comments: On my '06 4.4, I didn't need to remove anything to access the sensors. The driver side pre-cat had limited access due to transfer case, but the other three were easy. Also, the harnesses on the pre-cat sensors are a pain to unclip. I ended up breaking the locking tabs on both. It would be good to include a tutorial on how to unclip those. Thanks!
July 13, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Hinchcliffe Comments: Forgot, you do not need to use the O2 sensor socket to reach this one. A open end worked after a day of PB Blaster soaking.
February 2, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Hinchcliffe Comments: Just did my '05 4.8is, drivers front. No splash shields need to be removed for this one at least.
February 2, 2016
  Followup from the Pelican Staff: Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
always learning old school Comments: very very good post
January 4, 2016
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Privacy Statement]
 [Contact Us] [About Us] [Shipping] [Map to our Location] [Careers]

Copyright © Pelican Parts Inc.

Page last updated: Mon 12/5/2016 02:43:10 AM