Tip & How-To about Mercedes-Benz E-Class

CKP - Crankshaft position sensor

3.1) CKP - Crank shaft Position (sensor)

What is it? This is an electrical device that monitors the position of the crank rotation. The output from the CKP allows the ECU to determine the ignition timing, injection timing (in the absence of a cam sensor) and engine speed (revolutions). Generally if an engine has both crank and cam sensors it is the crank sensor that takes care of ignition timing and the cam sensor takes care of injection timing.

Where is it located? Most usually the crank sensor is located on the 'back' of the engine on the edge of the flywheel housing above the starter motor mounting or on the underside of the engine block; although in this position it is much more prone to stone damage, corrosion and dirt. On some engines the crank sensor is to be found on the front of the engine taking its measurements from the crank pulley. In this front position the crank sensor is often more exposed to the effects of dirt, water splash, oil leaks and heat as well as being more awkward to physically access.

How does it work? The device can employ several forms of detector. Some are passive, needing no electrical supply and include; inductive-magnetic (sine wave output), and reed type. These are typified by having just two wires connected to them. Some are active, needing a power source in order to operate and include: magneto-resistance (square wave); Hall-effect (square wave); and optical type. These are typified by having three (or more) wires connected to them.

The magnetic sensor is popular due to its simplicity and reliability, the Hall-effect type is also popular as it also reliable and its design allows for self diagnostic testing. The role of the CKP device is to detect the presence of magnet(s) or marker teeth on the periphery of the reluctor ring on the crank and to send pulse(s) back to ECU. The ECU reads these pulses and electronically triggers a spark at the appropriate point, advancing and retarding the ignition according to the speed of pulses being received. In older engines, perhaps where the cam sensor is absent, the ECU will initiate a spark every time TDC (top dead centre) is detected and each cylinder receives a spark every crank revolution even though ignition is only required on alternate rotations.

Symptoms of faulty crank position sensor

Associated OBD2 error codes DTCs: P0335 - P0339; P1345

  • Starting difficulty/failure/stall - If the faulty CKP timing problems are severe they may prevent the engine to fire, to fire and then stall, or stall at some random time without warning.
  • Hot engine shut off and failure to restart - The engine may start and run perfectly from cold but will begin to misfire or suddenly shut off after about 15 minutes once the engine has reached operating temperature. This effect is due to thermal expansion of the CKP body causing an intermittent break in electrical continuity and therefore the signal output to the ECU is interrupted. Sometimes the engine will restart but fail again after a further 15 minutes. On other occasions the engine will not restart until it has completely cooled down.
  • Misfire - miss-timed spark delivery caused by a faulty CKP signal can cause misfire and back fire events.
  • Hesitant acceleration, acceleration ceiling - Miss-timed ignition due to a faulty CKP signal can be exacerbated by increased engine speed. The engine maybe run evenly at idle but will fail to accelerate properly at higher revs until the engine reaches a power ceiling.

NEXT 3.1b) How to check and fix crankshaft position sensors

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crank sensor



Specific to:
Ford Taurus 2008-2009
Mercury Sable 2008-2009

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Fig. Crankshaft Position (CKP) sensor (7)


Specific to:
Ford Taurus 2008-2009
Mercury Sable 2008-2009
The Crankshaft Position (CKP) Sensor is a permanent magnet output coil device that monitors the speed and position of the crankshaft. A reluctor is attached directly to the crankshaft, and is used to generate a constant signal as it passes the CKP sensor magnetic coil. The CKP Sensor utilizes system voltage (12 volts DC), or reference voltage (5 volts DC) to generate a digital output signal to the PCM that is based upon a 0.5 volt AC reference. The alternating magnetic field is used by the sensor output electronics to produce a digital pulse. The CKP sensor returns a digital ON/OFF signal pulse during each revolution of the crankshaft, with a momentary signal interrupt for the top dead center (TDC) position of the #1 cylinder. The Pulse Width Modulation pattern is used by the Powertrain Control Module (PCM) to calculate ignition timing, fuel injector timing, misfire diagnostics, and the tachometer display

Jun 20, 2012 | 2008 Ford Taurus X

1 Answer

I changed the harmonnic ballancer and the sensor and got code p0336 didnt have this code untill I had to change harmonic.

P0336 Crankshaft Position Sensor A Circuit Range/Performance.

Potential causes of a P0336 code include:

  • Bad crank sensor
  • Broken reluctor ring (missing teeth, debris lodged in ring)
  • Reluctor ring dislodged/stripped from it's stationary location
  • Wiring harness chafing causing short
  • Wiring open in CKP circuit, good-day ! CKP=crankshaft position sensor. The Crankshaft position sensor also known as the crank position sensor is an electronic device used in an engine to record the rate at which the crankshaft is spinning. This information is used by the Electronic Control Module(ECM) to control ignition and fuel injection. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor. good-day !

Apr 03, 2012 | 2000 Pontiac Grand Am GT

2 Answers

van will not start code p0725 what to do

Without knowing make or model Po725 is a Chrysler code for Engine Speed Sensor Circuit
Possible Causes- - Open or shorted CKP sensor circuit condition
- Poor CKP sensor electrical connection
- Check communication error between the ECM and TCM
- Failed CKP Sensor
When is the code detected- The P0725 Codes is triggered when TCM does not receive the engine speed signal from ECM. Chrysler description- The Engine Control Module (ECM) monitors the engine speed through the Crankshaft Position (CKP) sensor with the engine running, and send signal to the Transmission Control Module (TCM

May 09, 2011 | Chrysler Town & Country Cars & Trucks

1 Answer

will crank but not start

Crank sensor may be bad. Crankshaft Position Sensor OPERATION Fig. 1: The CKP sensor trigger wheel rides on the front of the crankshaft. The missing tooth creates a fluctuation of voltage in the sensor 91194p63.jpg
The Crankshaft Position (CKP) sensor is a variable reluctance sensor that uses a trigger wheel to induce voltage. The CKP sensor is a fixed magnetic sensor mounted to the engine block and monitors the trigger or "pulse" wheel that is attached to the crank pulley/damper. As the pulse wheel rotates by the CKP sensor, teeth on the pulse wheel induce voltage inside the sensor through magnetism. The pulse wheel has a missing tooth that changes the reading of the sensor. This is used for the Cylinder Identification (CID) function to properly monitor and adjust engine timing by locating the number 1 cylinder. The voltage created by the CKP sensor is alternating current (A/C). This voltage reading is sent to the PCM, it is used to determine engine RPM, engine timing, and is used to fire the ignition coils. prev.gif next.gif

Aug 03, 2010 | 1997 Lincoln Continental

1 Answer

how do i install a crank angle sensor on my ford 1997E250 4.2L V6

FREE FROM ME TO YOU!!! I HOPE THIS HELPS YOU!! Sensor, Crankshaft Position (CKP) Removal
  1. Raise and support the vehicle.
  1. Remove crankshaft position sensor (CKP sensor) (6C315).
    1. Disconnect the CKP sensor electrical connector.
    1. Remove the (A) CKP sensor shield nuts and the (B) CKP sensor shield.
    1. Remove the (C) CKP sensor bolts and the (D) CKP sensor.

fc50791.gif Installation
  1. Install crankshaft position sensor.
    1. Position the CKP sensor.
    1. Install the bolts.
    1. Position the shield.
    1. Install the shield nuts.
    1. Connect the electrical connector.


Mar 25, 2010 | 2002 Ford E250

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