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How to Replace Driver side Upstream O2 Sensor 2004-07 Cadillac CTS

Created on: 2016-08-15

How to remove, install, change or replace an oxygen O2 sensor on 04, 05, 06, 07 Cadillac CTS

  1. step 1 :Removing the Wiper Arm
    • Pry off the wiper arm cap by hand
    • Remove the 15mm nut from the wiper arm stud
    • Pull the wiper arm off the stud
  2. step 2 :Removing the Cowl Panel
    • Peel off the weatherstrip
    • Remove the four 7mm screws from the cowl panel
    • Lift up and carefully release the passenger side of the cowl panel
    • Remove the 10mm nut from the driver side cowl panel
    • Remove the driver side cowl panel up and out
  3. step 3 :Removing the Wiper Transmission
    • Remove the two 10mm bolts from the wiper transmission assembly
    • Lift the assembly up toward the center of the vehicle
    • Disconnect the transmission wiring harness
  4. step 4 :Removing the Engine Cover
    • Remove the oil fill cap
    • Remove the engine cover
    • Reinstall the oil cap
  5. step 5 :Removing the Upstream O2 Sensor
    • Disconnect the O2 sensor connector on the backside of the engine
    • Loosen the O2 sensor with a sensor socket or a 22mm socket
    • Remove the sensor by hand
  6. step 6 :Installing the Upstream O2 Sensor
    • Install the O2 sensor by hand
    • Tighten the O2 sensor with an O2 sensor socket of 22mm socket
    • Connect the wiring harness
  7. step 7 :Installing the Engine Cover
    • Remove the oil fill cap
    • Press on the engine cover
    • Reinstall the oil cap
  8. step 8 :Reinstalling the Wiper Transmission
    • Connect the wiper transmission electrical connector
    • Insert the wiper transmission into place
    • Tighten the two 10mm bolts to the wiper transmission
  9. step 9 :Reinstalling the Cowl Panel
    • Insert the driver side cowl panel into place
    • Tighten the 10mm nut to the driver side
    • Insert the passenger side cowl panel into place
    • Tighten the 7mm screws to the panel
    • Press on the weatherstrip
  10. step 10 :Installing the Wiper Arm
    • Put the wiper arm onto the stud
    • Fasten the 15mm nut onto the wiper arm stud
    • Push on the wiper arm cap

Tools needed

  • Socket Extensions

    Torque Wrench

    15mm Socket

    O2 Sensor Socket

    7mm Socket

    Painter's Tape

    10mm Socket


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Hi, I'm Mike from 1A Auto. I hope this how-to video helps you out, and next time you need parts for your vehicle, think of 1AAuto.com. Thanks!

In this video, we're working with our 2006 Cadillac CTS, 2.8-liter, V6. We're going to be changing out our bank two, sensor one with a driver's upstream O2 sensor. If you like this information, please hit that subscribe button. We have a ton more information on this vehicle, as well as many other makes and models. If you want to buy these parts for your vehicle, they're available at 1AAuto.com. You can follow the link in the description.

Here are the items you'll need for this repair: 7mm, 10mm, 15mm, socket, ratchet, socket extension, O2 sensor socket, torque wrench, and painter’s tape.

Remove the black caps over the nuts for the windshield wiper arms. All you have to do is squeeze them together. Pop them off. We're going to use a small piece of painter's tape. You should use the straight edge to mark the position and angle of the wiper blade, so we can reinstall our wiper arms properly. Remove the two 15 millimeter nuts, securing the wiper arms down with 15 millimeter socket and ratchet. Work the wiper arms off of the splines. Do this by grabbing them at the joint, simply pulling up and pushing down. Eventually, it'll work its way off the splines, and you can remove your wiper arm.

Peel off the leather strip. Move these four 7 millimeter screws. We're going to use a 7 millimeter socket and ratchet. Lift up, carefully release this plastic, as it's hooked under the windshield. See the little hooks here, just be careful to pull out and away with those. Remove this 10 millimeter nut up against the fender on the driver's side. Lift up off of the splines for the wiper arms. Remove the driver's side of the cowl cover.

Remove these two 10 millimeter bolts securing the wiper transmission and assembly into the vehicle. It's a little easier to access this top one from the other side of the hood. We're going to use a 10 millimeter socket, ratchet, and extension. Lift up and toward the center of the vehicle to release this tab. Flip over the assembly. Release the connector. Remove the assembly from your vehicle.

We're going to remove the engine cover to make it easier to gain access to the backside of the engine, and because I'm going to have to lay across the intake to get back there. We don't want to risk breaking the plastic. Remove the oil cap. Lift up and pop off the cover. Reinstall the oil cap to prevent any dirt and debris from falling in while we're working.

The connector for the O2 sensor is located here, on the back side of the engine. We're going to reach down, slide it toward the center to remove it from its clips, and release this yellow safety. It pulls back. We push down, and pull the connectors apart.

Install the O2 sensor socket, or a 22 millimeter wrench, over the sensor. Once you've cracked the sensor loose, you should be able to remove it the rest of the way by hand. Remove the sensor from the vehicle.

Here we have the two upstream O2 sensors that we removed from our 2006 Cadillac CTS 2.8-liter V6, and our new part from 1AAuto.com. As you can see, both old sensors are identical to each other, as well as the new sensor.

We have the same 22 millimeter hex, same threads, same tip on them. The new one comes coded in an anti-seize lubricant to prevent it from walking into the exhaust after you install it. We have the same length wires wrapped in a heat treated coating to keep them from melting, being along the back of the engine and the exhaust. The connectors themselves are the same on all three components.

A new one actually comes with a new clip. Sometimes these break off, or get stuck in the motor. Ours are stuck in the engine, so if we want, we can simply pop that off, lock it back into the connectors that are already there, or we can pry these out of the motor. Have a nice, fresh tab to hold this in place. Faulty oxygen sensors can be the cause of rough running conditions. Lean or rich engine codes, as well as being partially responsible for the PO420 catalytic converter codes that are common on a lot of vehicles. If you've narrowed down that the upstream O2 sensor is the cause of any of these issues for you, this new part from 1AAuto is going to go in direct fit, just like your original equipment, and fix you up right.

Reinstall your driver's side O2 sensor. Install your O2 sensor socket, or a 22 millimeter wrench. Tighten down the O2 sensor the rest of the way.

Remove the socket. Send the connector back up behind the wiper motor so we can reconnect it from the top. Reconnect the electrical connector. Snap the safety into place. Mark the connector back into its retainer. Reconnect the electrical connector. Set this opening onto the pen. Start tightening down your two 10 millimeter bolts.

Reinstall the driver's side of the cowl cover first. Be sure that all the plastic hooks line up under the windshield. Reinstall the 10 millimeter nut. Reinstall the passenger side of the cowl cover. Again, make sure that all these hooks line up and go underneath the windshield. Reinstall your 7 millimeter screws. Reinstall the rubber seal, the channel simply presses onto this ridge here.

Line up your wiper to the tape mark we made on the windshield earlier. Torque to 26 foot-pounds. Line up your wiper to the tape mark we made earlier. Start the nut by hand. Torque the nut to 26 foot-pounds. Reinstall the plastic cap. Close the hood, remove the tape marks from the windshield. Check for proper operation of your wiper motor.

Thanks for tuning in. We hope this video helped you out. Next time you need parts for your car, please visit 1AAuto.com. Also check out our other helpful how-to and diagnosis videos.

2006 - 2007  Cadillac  CTS
2005 - 2005  Cadillac  CTS
2006 - 2007  Cadillac  STS
2005 - 2005  Cadillac  STS
2004 - 2005  Cadillac  CTS
2006 - 2006  Cadillac  SRX
2005 - 2005  Cadillac  SRX

03-07 CTS w/2.8L; 05-06 SRX; 05-07 STS w/3.6L; 06-09 STS w/4.6L Upstream Oval Con O2 Sens LF=RF (AC)

Cadillac CTS SRX STS O2 Oxygen Sensor ACDelco 213-3240

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  • Quality Tested - built to a strict level of product standards.

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