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Front O2 sensor procedure (long) Posted by sam96CS [Email] (#852) [Profile/Gallery] (more from sam96CS) on Wed, 14 Sep 2016 21:16:47 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I decided to replace my front O2 sensor when a P0133 code wouldn't go away by itself and the catalyst monitor wouldn't run. The Trionic engine management system is fussy about O2 sensors, so I bought the Bosch 13662. Believe me, this job is too much of a hassle to take a chance. The Bosch 13662 is the exact part. Plug and play. No splicing.
The check engine light turned off at a stop sign within 2 miles of home after installing the Bosch 13662. The catalyst monitor ran during the first trip to town after installing the new sensor, about 13 miles each way. To put that in perspective, the catalyst monitor hadn't run in the past 2+ years and 20,000+ miles because the old sensor was "too slow".
The procedure below isn't exactly what I did. It is what I would do if I did it again. Everything can be done from above the engine bay. When you remove the old sensor, start at the electrical connector and work your way back to the sensor. When you install the new sensor, start with the sensor, then do the cable management and finally make the electrical connection. Here are 9 steps:
1. Undo the old sensor's electrical connection. It is located almost straight down from the oil fill pipe. It helps to have a flashlight and a mirror for this step. There are several electrical connections in same area, so make sure you find the right one. It is located beside the electrical connector of the rear O2 sensor. First you take off the electrical connector which has a red latch that has to be pushed to the open position. I got it started by hand, then used the end of a screwdriver to force it open fully. Then it just pulls off. The O2 sensor's connector passes through a metal plate and is held there by a plastic latch. Squeeze the latch while pushing the connector through the plate. I didn't note the orientation, and I'm pretty sure it will pass through the plate only when oriented correctly.
2. Free the cable from whatever is holding it in the space below the intake manifold. Mine had 2 zip ties, one holding it loosely to the oil filler tube and another holding it loosely to a hose. I cut the zip ties with scissors.
3. Pull the cable out of the space below the intake manifold. You'll find that the cable is attached to a metal coolant pipe located near the bottom of the head on the belt side of the engine. Two metal spring clips hold the cable to the pipe. The coolant pipe clips can be rotated by hand until you see a tab. Hold the clip still with the thumb of one hand while pressing down on the tab with a long screwdriver. The clip will release from the coolant pipe and then possibly fall to where you'll never find it. I managed to save 1 out of 2 clips , and one is enough to keep a cable away from the belt and pulleys.
4. The last thing that secures the cable is a clamp that is bolted underneath the a/c compressor where it is very hard to see and reach. Don't be stupid like me and remove the 13 mm bolt. Instead, snip off the old sensor's connector and from the sensor side pull the cable through the clamp. If the clamp is pinching the cable too tight then you'll have to loosen the bolt a little.
5. Unscrew the sensor from the exhaust manifold. I sprayed mine first with PB Blaster and let it soak a few minutes, then used a 7/8" open end wrench. Yes, I'm lucky to live where people salt their grits, not their roads. The 20 year old sensor was no tighter than a spark plug. If you are less fortunate then there are videos online that show how to loosen a sensor that is rusted in place and then clean the bung's threads.
6. Check the threads of the new sensor. If it is a Bosch 13662 like mine then it already has some anti-seize on the threads. Screw it in, and make sure you help the loose cable rotate with the sensor so wires don't get twisted. I snugged the sensor with a 7/8" wrench about as tight as an oil drain plug.
7. Route the cable through to the belt end of the engine. Zip tie the cable to the clamp that the old cable was routed through. I wish I had done that. It might be easier to get the zip tie started on the clamp, then feed the connector and cable through the zip tie, then snug the zip tie and trim the excess zip tie plastic as needed.
8. Now feed the connector end of the cable into the space below the intake manifold. This is similar to trying to push a string. I pushed the connector with the right hand while reaching from the other side with the left hand to pull it through. Pull until there is no slack in the cable on the belt side of the engine. It must not touch the belt or any pulleys. Clip it to the coolant pipe. I guess you can use zip ties if you lost the clips at step 3 above.
9. Insert the connector end through the metal plate and push until it latches into place. Now connect the electrical connector that has the red latch. This is really hard to see, and I did it by feel. Secure the cable with zip tie(s) as needed in the space under the intake manifold. Wash up, record the date and mileage, and grab a refreshing beverage of your choice.
->Posting last edited on Thu, 15 Sep 2016 04:56:56.
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