Mercedes-Benz Parts Catalog Mercedes-Benz Accessories Catalog Mercedes-Benz Technical Articles Mercedes-Benz 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    
 >  >
Crankshaft Position or Engine Speed Sensor Replacement
 
Bookmark and Share

Pelican Technical Article:

Crankshaft Position or Engine Speed Sensor Replacement

Steve Vernon

Time:

3 hours3 hrs

Tab:

$40 to $80

Talent:

**

Tools:

8mm universal socket, Philips head screwdriver

Applicable Models:

Mercedes-Benz W123 (1977-85)

Parts Required:

Crankshaft or engine speed sensor

Hot Tip:

Remove the fan

Performance Gain:

Smoother running car

Complementary Modification:

Check water pump

The crankshaft positioning sensor tells the car's computer where the flywheel is located in relation to the combustion cycle. On the 1985 Mercedes W123 300TD the crankshaft positioning sensor is used for diagnostic purposes only and does not affect the performance of the vehicle.

Due to the location of the sensor behind the water pump pulley, a lot of components need to come off the vehicle so you can access the sensor. This is not a quick job so make sure you factor in all the time needed to remove and replace all the other systems before starting.

Over the years your car may have been serviced by multiple people including previous owners and this can lead to parts replaced with different size fasteners and hardware. 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.

Our vehicle may vary slightly from yours as Mercedes redesigned systems and sub-system as the models developed over the years. If something is different on your vehicle please let us know and share your info to help other users. If you have any questions or comments or even a different procedure you would like to share please leave it below and please leave your vehicle information.

The CPS is located down behind the water pump pulley (red arrow); to access it you will need to start by removing the fan and shroud, please see our articles on these procedures for additional assistance.
Figure 1

The CPS is located down behind the water pump pulley (red arrow); to access it you will need to start by removing the fan and shroud, please see our articles on these procedures for additional assistance.

You can see the dirt and oil covered sensor and mounting bracket here (red arrow).
Figure 2

You can see the dirt and oil covered sensor and mounting bracket here (red arrow). You will need to remove the belts that drive the water pump and alternator to remove the water pump pulley. Please see our article on replacing your belts for additional assistance.

With the water pump pulley removed you can get at the 8mm retaining nut (red arrow).
Figure 3

With the water pump pulley removed you can get at the 8mm retaining nut (red arrow).

The right tool is a universal 8mm socket; this is one of the few tools that will fit into the space and not strip out the retaining nut.
Figure 4

The right tool is a universal 8mm socket; this is one of the few tools that will fit into the space and not strip out the retaining nut.

Pull the sensor (yellow arrow) out from the mount (red arrow).
Figure 5

Pull the sensor (yellow arrow) out from the mount (red arrow).

Trace the sensor cable back through the engine bay, removing the zip ties as needed, until the cable ends at the diagnostic terminal (red arrows).
Figure 6

Trace the sensor cable back through the engine bay, removing the zip ties as needed, until the cable ends at the diagnostic terminal (red arrows).

The sensor provides information to terminals 7, 8 and 9 (red arrow) but cannot be removed without taking the terminal out from its mount.
Figure 7

The sensor provides information to terminals 7, 8 and 9 (red arrow) but cannot be removed without taking the terminal out from its mount. Use a Philips head screwdriver and remove the two screws.

Flip the terminal over and gently pull the end of the sensor cable from the terminal.
Figure 8

Flip the terminal over and gently pull the end of the sensor cable from the terminal. Installation is the reverse of removal.

Bookmark and Share

  Search our site:    

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

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping] [Careers]

Copyright © Pelican Parts Inc. -    DMCA Registered Agent Contact Page

Page last updated: Wed 12/7/2016 03:01:44 AM