another problem.

lets start from basic...

desynchronize system with HHT (hand held tester) and then resynchronize all infrared remote control keys for this vehicle.

possible problem is timing with transponder at CAN (controller area network) interface.

you really need to have a diagnostic computer in this case. i need the fault code as well.

 

1. What's a CPS?

2. How do you justify if the timing with the transponder at the CAN is not accurate? It seems that the replacement of an IFZ Control Module doesn't seem to rectify the problem.

 

CPS - crankshaft position sensor.

the timing to CAN is interrupted by the interior motion sensor.
he got a different car and system. it can't be the same with yours. he might end up replacing the control module... or already did. i can feel his car is okay now, and just trying to get some answer...?

 

Thanks much for the qucik response SleepWalker, I don't have HHT but when I called benz road side assistance. Technician brought computer with him, he hooked up wih the car but it wouldn't read it. It would say turn on the ignition when the ignition is already on

 

please check the fuse number 17. was it okay?

on the diagnostic socket, was there a power on pin number 3 with ignition "on"?

 

Does a faulty MAS (Mass Air Sensor) contributes to intermittent starting failures?

 

no.

the car have emergency or "limp home mode" function.
the check engine light will be "on".

the car can still start and be driven even without the air mass sensor. during this operation, the engine control unit will adjust the injection time according to the position of throttle valve only.

 

Hey Sleepwalker,

1.Just referring back to your old post, the red circled portion--> Control Area Network

2. Ok, the IFZ and the ECM are new. There seems to be a signal interruption whenever i fail to start my car.

3. Just one question, the transmission of signals in the CAN between the IFZ and ECM, are there wires connecting between to these 2 control modules for the transmission? If yes, i think i would request the technician to unplug and replace the wires, maybe it would work?

This is because when the 2 control modules were being replaced respectively, maybe the wires connected to these modules (if there are any) were being slightly tampered even so that the car could start, but sometimes the signal may be interrupted. Just thinking aloud.

cheers

[IMG]local://upfiles/3076/E1933849C163448C9921C1774B52377C.jpg[/IMG]

 

yes. there is two wires for CAN-bus.

CAN low is green and CAN high is white.
you can see it from the wiring diagram i sent previously.

am afraid the wire just for CAN-bus cannot be replaced separately because it is together with the wiring harness. unplugging it is possible for testing purpose.

now you are planning to give the mechanics an instruction on how to do the job. i think they have all the advantages compared to us because they have all the knowledge and equipment to explore all possibilities... not to mention that the car is all on their hands now.

checking all the connectors is a good idea. presence of dirt or oil on other control unit that uses CAN will surely affect all. have the other control unit check as well for good connection and cleanliness.

just a small idea: if either one of the CAN is disconnected or grounded, the other CAN will automatically take over. the faulty CAN will be disabled by the system and a fault code is put into memory. if there is something that disrupts the two, then that could be the culprit.

so once again, just advise them to check well... CAN included.