No Crank No Start Mercedes benz

There are many reasons for no crank no start in mercedes benz. when the scan tool is not able to read or do communicate with engine control module or transmission control module. this could be happen due to some reason like CAN communicatoin , power supply to the engine control module, or transmission control module, or engine control module or transmission control module it self is faulty. when no communication occurs with ECU or TCM there will no crank no start. also it may be possible that there is no Transmission indicator P will be illuminate on cluster meter. in this case it might be possible that fan run at high speed when ignition is turn on.

As there are many reason for no crank no start in mercedes benz. One of the measure reasone behind this fault in vehcile is CAN connectors. In merecedes there are 5-6 CAN connectors some are located at the front left floor below carpet and some at front right floor below carpet. these CAN connectors is use to make communication between all the control module present in vehicle. Like Engine control module, Transmision control module, ABS, EPS, Park assist control module, gateway, front SAM box, Rear SAM box, electronic ignition switch etc.

Transmission indicator PRND on Cluster Meter

How to trouble shoot No Crank No Start Mercedes benz :

CASE#1 :

In case of no crank no start in mercedes benz first of all check transmission indicator P on cluster meter. cluster meter should show that the transmission is in P position. If it is not showing that the transmission is in P position. than go to scan the vehicle with scan tool, if in some control module like ECU, TCM, ESP there is CAN communication bus off fault is store. then mechanic need to check the CAN connectors located below the carpet at passenger and driver side. the CAN connector might be short or inoperative due to water damage. if found damage at the CAN connectors than change it that can be solve the problem of no crank no start.

CAN Connector

CASE#2

STEP#1

Power supply from battery to all the control module present in the vehicle is use to supply from fuse box present near the battery. from this fuse box the main power suppy is transfer toward all the control module. like front SAM box, Rear SAM box, alternator, starter, power steering control module, electronic stanilty control module etc. first check the power supply form this fuse box to all the control module which is connected to it. power suppply should be present at all the control module. if any one control module above them is not getting power supply then go to check that fuse box. there is number of fuse located inside that some time they may get blown. when they get blown it will stop supplying power to the control module. it can be solve by replacing that fuse with new one. If all the control module is getting power suppy than that mean this fuse box is good.

STEP#2

After it go to check all the fuse present at the front sam box change if any blown. check all the relay present on sam box for its function change if any one is not working. if there is no power supply present at the fuses and realy which is coming from sam box. that it is clear that the fuse box is itself faulty. replace faulty fuse box do programing and coding.

CASE#3

Mechanic need to scan the vehicle with the help of scan tool scan whole system of vehicle. check for the communication with all the control module present in the vehicle. When there is no communication with ECU & TCM occurs, it might be serious problem to solve. Also check trnasmission indicator light P is showing on cluster meter or not. it should show P if it is not than first of all go to check the CAN connector for any damage or short. if any can connector is not looking good or rusty than change it. If these CAN connectors are good and there is no any short take place.

Then the second thing you need to check power supply from battery to fuse box (FUSE F32) located at the front left of near battery. fuse box located near battery is used to supply power to front and rear SAM box and all other control module. check power supply at front SAM box, there should me 12V on each fuse at sam box. check all relay 15R, 87R or main relay on fuse box for any failure. if all good then check the power supply at engine control module. if power supply and igtion current is reaching till ECU than it is confirm that the problem is in Engine control module(ECU). changing engine control module with coding and programing can solve problem.

Remove small socket cover ( do not disconnect socket from ECU ) of engine control module turn on the ignition switch check power supply at ECU if there is 12 volt present at engine control module. then engine control module it self is faulty.

Engine Control Module

Causes of No Crank No Start Mercedes benz :

  • Faulty engine control module.
  • Faulty CAN connector.
  • Failure of from SAM box.
  • Also Faulty electronic ignition switch (EZS).
  • blow fuse box (fuse 32)
  • faulty transmission control module.

Symptoms of No Crank No Start Mercedes benz :

  • No crank no start.
  • No transmission indicator P will illuminate on cluster meter.
  • Also fan will run at high speed.
  • No communication with ECU & TCU.
  • ignition turn on but does not crank.

Solution :

  • Replace faulty engine control module.
  • Repair or replace faulty or shorted CAN connector.
  • Replace faulty front SAM box.
  • Also repair or replace faulty fuse box F32.
  • Repair or replace faulty ignition switch (EZS).
  • Replace faulty transmission control module.

special notes :

No crank no start in mercedes benz can be happen due to many reasone. so do not change any control module before diagnosing properly with the help of scan tool. when this problem happen first check transmission indicator P on cluster meter. if it is not there no cluster meter then go to follow the CASE#1 procedue. if the problem is gone after following it then go to follow the CASE#2 procedure to solve the problem.

in this case there may be one more reasone accept those two which is short circuit at the wiring loom. the wiring loom which come from inside to outer side fuse fox through below the battery. that goes under short due to block water drainage water get store below the battery.

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