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How to replace the CPS - Crankshaft Position Sensor

37K views 17 replies 15 participants last post by  Kraut56 
#1 ·
For a great write-up already go here:
How to replace the Crank Position Sensor (CPS) - S500 - MBWorld.org Forums

However, the '03 model throws a bit of a curve ball at you. This is what the '00 model looks like back there. I don't know how he got this shot...it's a terrible, horrible, no good, very bad angle and yet the shot is amazingly clear.


The '03 model has it a little different, in all the bad ways.


The plate is extended all the way up to the second torx screw. That it impossible for me to squeeze the connector out. I tried like hell and my right hand got several cuts from the efforts, but it is just not possible.

My way around it was to not actually remove the connector but just remove the E8 torx bolt blind and use the connector and line to fish the CPS out.

Awesomely enough, that was the perfect way to do it. All I had to do was line the 12" extender to the E8 bolt blindly and turn until the bolt was off and fish the CPS attached to the connector. It slid off with no resistance and putting it back on was exactly the same.

From the time I thought about the idea to actually making it work was 6 minutes.

Hopefully this will help someone out there. It was only because I know that the bolt was underneath the CPS that I could have figured this out. Without that photo, I wouldn't have. Thanks internet and here's my thank you back.
 

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#4 ·
No need to remove the sheild.
If you have an E8 female Torx Socket, a 1/4 ratchet and 8-12in. extension, all you have to do is blind set the tork socket underneath the CPS and the wire that connects to it.

The small space works to your advantage then as the sheild becomes a guide of sorts.

Once the Torx Screw is loosened, keep the torx socket on the screw and place the CPS wire in line with the socket extension bar and "fish" the whole CPS using the wire socket as your line. The CPS will magically glide out as you pull the line, there is absolutely no resistance, and if there is, the screw might not be unscrewed all the way. There are no other things attaching the CPS to the car.

Good luck and may the force be with you.
 
#7 ·
I did on my CLK 320 few days ago.

It takes me few day's work to re-put the screw on the position after the new sensor has on its position. It is impossible to let the screw insert to the sensor hole due to very limited space.

Finally, unplug the sensor and use a small rubber ring to fasten the screw with the sensor. then re-insert the sensor with the screw at the same time. I think it is the best solution!

Use a wire type flexible torsion shaft connects with the E8 female Torx Socket by TAPE.

To turn the screw in by bending the flexible shaft let the socket just up right in-line with the screw.

Use a ratchet to apply the right torque to the screw.
 
#8 ·
You can remove the wire clip on the sensor by using your left hand with a screwdriver while pulling up on the wire with your right hand. While kneeling on the engine, go around the air intake with your left hand. You can actually reach all the way to the sensor with your left hand. Use the screwdriver to depress the clip and pull up on the wire with your right hand. To install the new sensor, use a 3-inch extension with the socket on the bolt and hold both firmly with your right hand. Use your left hand to reach around and meet your right hand to help hold the sensor. Using both hands, insert the sensor while keeping pressure on the bolt with the 3-inch extension and socket. Once the sensor is inserted, you will have to move the extension until the bolt meets the threads, then tighten with hand pressure. Finish tightening the bolt with the wrench.

This job would be so much easier if the bolt were on the opposite side of the sensor and if the bolt was unable to separate from the sensor. One or the other changes should be adopted by Mercedes to make this a 10-minute task.
 
#10 ·
Guys excuse if I post something that is already answered but here is a lot of posts and I can not find real answer.

I had situation last night, I was driving maybe 65mph and my s430 2001 just died in middle of driving on interstate.
He stayed in drive until I parked on shoulder and I sawed some sparks on back, they were coming from exhaust.
My display says battery died plus check engine.
I bought new battery couple days ago, I don't think that battery is problem.
When I turn my key to ignition it's everything normal but when I try to start, no sound.
I was looking around and some people told me that maybe my key don't communicate well with car or may be that crank position sensor.
If someone have similar problem please help me.
I already ordered cps from eBay for $20. New one. I will replace but can it be something else ? Why sparks ?
Thank you and excuse my English is not perfect.
 
#11 ·
Hello All. I was hesitant to do this job myself, but from the great posts here I did. I bought the sensor for $35. and a 12" flexible extension, and replaced the CPS about 3 weeks ago. The entire job took me 10 minutes (with several minutes wasted from me dropping the bolt between the bellhousing and the metal shield plate). I found it to be a very simple job. What I did was lay a blanket over the engine and front of the car. I laid on top of the engine, used my left hand to feel the sensor, and right hand used the tools. I didn't have any problem removing the wire harness. The flexible extension was a must, and I feel it would be impossible to do without it. After I removed the bolt, I was able to turn the sensor slightly both directions with my left thumb and index finger while applying upward pressure at the same time and it slid out very slowly. I kept my left hand there to guide the new sensor in and had no problem replacing the bolt. My car has been running great ever since. I'm very grateful for all the posts, pictures, and suggestions.

Issues I was having that lead me here:
I was driving on the highway and the car just turned off, it wouldn't start for several minutes. A few weeks later it did it again while stopped at a red light, it took around 30 minutes to finally start. I was going to take it home from there and it turned off again and wouldn't start, after nearly an hour of trying to start it, I had to have it towed home. I am no mechanic. I'm 6' 200lbs, and had no problem doing this job. I hope this can help others as well.
 
#16 ·
2004 E500 Wagon

Due to limited space, it is best to remove the air intake duct behind the engine as depicted in the YouTube video:

This way you have access with two hands!

To avoid frustration:

1. Place rags or paper around the area to catch dropped screws or tools.
2. With electrical tape, tape the junctions of the tool assembly so they will not separate. (i.e. socket to extension etc.)
3. Tie a fish line or kite string to the top end of the extension so that it can be easily recovered if dropped.

The most time consuming part is the preparation.

=
 
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