My tips for W203 C55 CPS (crankshaft position sensor) replacement
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From: Atlanta Metro
Current: C217 V12TT AMG Previously: C55 AMG, SL65 AMG
My tips for W203 C55 CPS (crankshaft position sensor) replacement
[helping out the community for future search results]
The issue: Cranks fine under cold start, struggles to start during a hot start (turn off car then turn it back on in 5 mins).
Part: My part actually came in a Hella box, and the last four numbers were 28 28. The last four of the original part in the car were 27 28, which made me weary at first given compatibility problems.
Steps:
1) Take off the airbox (and ram pipes, front clip, etc).
2) Take off the MAF sensor (unplug the connector on the driver side, move stuff around)
3) Take off the inlet elbow below the MAF (also unplug a rubber hose)
4) Find the CPS sensor. It's hidden, try to use a mirror. It's on the driver side, behind the block, on top of the trans case, at around 2 oclock.
Big note: I used the "reach around" method (yes, you know it well!). Standing on the passenger side, squeeze your left hand and arm between the block and firewall, and find the sensor, connector, and bolt below the sensor.
5) Using your right arm, grab your 3/8" ratchet, 6" extension, U-joint, 3" extension, and E8 socket, feed it through the cables from the top of the car, and use your left hand to grab it and place it onto the bolt head. Remove bolt.
Big note 2: Remember the bolt is around 2 oclock (when facing the car). Because of this, your socket/extensions will not be horizontal, nor vertical, in comparison to the bolt. They will be at an angle.
6) Rotate the sensor around to break it free then rotate it up and out.
7) Unplug it
8) Put in the new sensor; remember this is a blind operation, and the sensor hole is tight so it will take some maneuvering.
9) Put your car back together. Don't forget to plug in the MAF sensor.
Cross your fingers and turn the car on.
I had no CEL's pop up before or after; only "issue" I'm having right now is that the transmission is shifting a little bit harder, and it seems like it's shifting somewhat delayed. I think there will need an adaptation over time, so the engine knows when to cut ignition during shifts to smooth out the driving experience. So obviously changing the CPS has done something, and/or I forgot to plug something in (or I messed up my MAF in the process).
My hot start trial today seemed to work; it didn't crank like it does during a cold start, but it didn't struggle/stumble during the hot start. More time will tell. Good luck guys hoped this helped.
The issue: Cranks fine under cold start, struggles to start during a hot start (turn off car then turn it back on in 5 mins).
Part: My part actually came in a Hella box, and the last four numbers were 28 28. The last four of the original part in the car were 27 28, which made me weary at first given compatibility problems.
Steps:
1) Take off the airbox (and ram pipes, front clip, etc).
2) Take off the MAF sensor (unplug the connector on the driver side, move stuff around)
3) Take off the inlet elbow below the MAF (also unplug a rubber hose)
4) Find the CPS sensor. It's hidden, try to use a mirror. It's on the driver side, behind the block, on top of the trans case, at around 2 oclock.
Big note: I used the "reach around" method (yes, you know it well!). Standing on the passenger side, squeeze your left hand and arm between the block and firewall, and find the sensor, connector, and bolt below the sensor.
5) Using your right arm, grab your 3/8" ratchet, 6" extension, U-joint, 3" extension, and E8 socket, feed it through the cables from the top of the car, and use your left hand to grab it and place it onto the bolt head. Remove bolt.
Big note 2: Remember the bolt is around 2 oclock (when facing the car). Because of this, your socket/extensions will not be horizontal, nor vertical, in comparison to the bolt. They will be at an angle.
6) Rotate the sensor around to break it free then rotate it up and out.
7) Unplug it
8) Put in the new sensor; remember this is a blind operation, and the sensor hole is tight so it will take some maneuvering.
9) Put your car back together. Don't forget to plug in the MAF sensor.
Cross your fingers and turn the car on.
I had no CEL's pop up before or after; only "issue" I'm having right now is that the transmission is shifting a little bit harder, and it seems like it's shifting somewhat delayed. I think there will need an adaptation over time, so the engine knows when to cut ignition during shifts to smooth out the driving experience. So obviously changing the CPS has done something, and/or I forgot to plug something in (or I messed up my MAF in the process).
My hot start trial today seemed to work; it didn't crank like it does during a cold start, but it didn't struggle/stumble during the hot start. More time will tell. Good luck guys hoped this helped.
Last edited by Viper98912; Sep 7, 2013 at 09:06 PM.
