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Stan, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3526
Experience:  Technical support engineer
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Hi,i have a 2002 mercedes 311cdi sprinter,last week went to

Customer Question

Hi,i have a 2002 mercedes 311cdi sprinter,last week went to change the battery,fitted new battery and reset radio code,went to start vehicle and as normal panel lights all lit up but whereas they all normally go out after a couple of seconds,the heater plug light,the edc light and the fuel filter warning light all stayed on and on turning the key to the start position nothing happens,have checked all fuses,nothing else has been done to the vehicle exept for changing the battery,the van is now completely immobile and miles from any mercedes dealer so would rather not hear about plugging in to a diagnostic machine,just to affirm that the only item that has been changed is the battery which was done correctly,need van for work so a speedy reply much appreciated,thanks peter
Submitted: 7 years ago.
Category: Mercedes
Expert:  Stan replied 7 years ago.


Do you have Start Error message in the Instrument cluster? are the radio and blower operational with ignition on?

Best Regards,


Customer: replied 7 years ago.
There is no error message in the instrument cluster,the radio and blower work fine in fact its much easier to hear the radio now as i dont have to worry about the noise from the engine!!!!
Expert:  Stan replied 7 years ago.

The reason for asking this is because the immobliser system recieves ignition 12v from the same fuse as blower and radio. So the fuse is definately in order. No start error message indicates that immobiliser should work fine.

If engine does not start in this case that might mean that engine control unit does not recieve ignition signal. If the glow plugs do not activate when ignition on, that would be a confirmation. Unfortunately i do not have the relay positions at the moment to provide you. i will have this info in 12 hours. If you feel that my answer is unsatisfactory at the moment, you have the option to opt me out and not to accept my answer, so that other experts could assist you.

I will be back online in about 12 hours, then i would be able to give more info.

Hope for you understanding,





Customer: replied 7 years ago.
Thanks i,ll stick with you,could the problem be in the heater plug relay box,i,ve noticed recently with the van that even though the heater plug light on the dash appears to work correctly i.e. comes on with the ignition and goes out after a few seconds the van has required more of a turnover on a cold morning and it is my belief that there has been no power reaching the heater plugs,its a bit difficult to tell at the moment due to mild weather,this is of course before the present problem with the light staying on all the time.thaks for your perseverance,peter.
Expert:  Stan replied 7 years ago.

Hi Pete,

If there would be a problem with glow plugs, the glow plug relay light would be on after an engine start. THe longer start is probably due to one of the injectors leaking too much fuel into return line.

Could you provide me with a VIN of your car, i need to find vehicle-specific diagrams to find the solution.



Customer: replied 7 years ago.
Hi,the vin no. is WDB9036632R465609,so as not to lead you astray i,m 99% sure that in the past even though the heater plug light has functioned correctly power has not been reaching the heater plugs,peter.
Expert:  Stan replied 7 years ago.
Ok, i have the diagrams for the van now. Please check if the horn is working and there is 12v present at pin2 of the dignostic socket with ignition on?
Customer: replied 7 years ago.
horn works and 12 volts indicated on position two of diagnostic socket,(not numbered but looking directly at socket top row 2nd from left)
Expert:  Stan replied 7 years ago.

If you got the right pin, there is no voltage when ignition off.

Older Sprinter models indicated immobiliser failures by glowplug light. Your Sprinter should indicate it by start error message. Since there is no message i assume that no fault on drive authorization. So if the ignition is on and starter shorted, engine should fire. Since it does not, ECU does not see the ignition on. One more thing to check would be the voltage supply of it. Would the engine control unit wiring diagram be useful for you?


In my experience, the problems causing failure to start were fuses, immobilizer ,engine control units or ignition keys needed to be reprogrammed.

Customer: replied 7 years ago.
There is no voltage with ignition off,wiring diagram probably helpful but am not the greatest electrician,it seems we can rule out fuses,and immobilizer,leaving me with either a faulty ecu or the key needing reprogramming(can they loose the program just by disconnecting the battery?) sorry to be a pest but am desperate,peter.
Expert:  Stan replied 7 years ago.

Hi Peter,

For one reason or the other my explanation for opting out did not go through. I am sorry for this.

I opted out because the only step i see is to diagnose the malfunction with Star Diagnosis scantool. The memory of the immobiliser can be lost by disconnecting the battery. It is absolutely not normal but possible.

Maybe other experts have more knowledge on this malfunction, or the solution without using diagnostic equipment. I will keep my eyes and ears open for possible solution, and if i will get it- i will reply to you immidiately.

Please reply to this post for other experts to see it.

Hope for your understanding,