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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 52999
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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2000 mercedes ml430. No crank. When key is turned to start

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2000 mercedes ml430. No crank. When key is turned to start all the dash bulb check lights come on and stay on but will not crank. Also, won't shift out of Park (have not had a chance to check brake switch yet for this issue.) Battery voltage is 12.78V. Scanner will communicate will all modules except TCU. Two scanner codes that may apply are C1024 Bus fault communication with EGS/ESP and B1040 CAN Bus: Communication error.

Hi, my name is***** you inspected the TCU for oil contamination? It's not unusual for the electrical connector on the transmission to leak fluid and allow fluid to wick up the wire harness and into the TCU.

Customer: replied 3 days ago.
TCU is bone dry. I've replaced 13 pin connectors/o-rings before for this issue and conductor plates on the 722.6 before.
Customer: replied 3 days ago.
The no crank is the primary focus so I can check the transmission fluid level and move on from there. Could the immobilizer/anti-thefy cause the no crank issue?

Usually with an immobilizer problem you will get a short crank or a crank/no start. You should also have immobilizer codes. Have you checked the starter itself? Have you bypassed the starter relay to see if the starter works?

Customer: replied 3 days ago.
The starter works. Trying to figure out what is preventing the signal from going to the starter relay (really is good) to energize it. Could the TCU or EGS be the issue?

Ok, yes the TCU and the shifter both send park recognition signals to the ECU to authorize cranking. On a Mercedes scan tool you should be able to see actual values to see if the starter is authorized.

Customer: replied 3 days ago.
One more detail. When the key is turned to start I do not here the full pump run. Would the TCU/ECU prevent this as well. I don't have Mercedes scan tool. I have a Snap-on Modis Ultra with the European software/adaptors.

The fuel pump is probably running you just may not be able to hear it. Depress the valve core on the fuel rail and see if you get a good spray of fuel. It should not be related to this problem unless you have a bad ignition switch.

Customer: replied 3 days ago.
Given the CAN errors I mentioned before is there a way to check the CAN signals between the EGS and TCU to try and determine which maybe faulty?

Your CAN codes are probably due to the fact that the TCU is not communicating on the CAN. Have you checked power to the TCU? Fuse 16 and 22 power the TCU and the shifter.

Customer: replied 2 days ago.
I not only check those fuses but all fuses and all were good. What about the grounds for the TCU and EGS and where are they located?

Right kick panel and under the driver's seat. I doubt it's a ground problem. When you turn on the key does the instrument cluster show that the transmission is in park?

Customer: replied 2 days ago.
Brake pedal switch is good. With KOEO (run position) the dash does not show what gear the transmission is in but all the check/warning lights remain lit.

It sounds like you have a bad electronic gear selector module.

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