BMW 523Li 2009 Oil Level Inactive DME 2E7C Trouble Repair

A BMW owner drove his BMW with 110 thousand miles to our garge for repair his console trouble, oil level inactive.Here I share this repair case which caused by DME trouble,hope it can give you some inspiration for you work.

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Vehicle Information:

  Model:BMW 523Li

  Year:2009

  Mile:110,000 miles

  Trouble:Oil level Inactive.

 

Trouble Diagnose:

Our technicians use ISTD to diagnosed and found the trouble:

DME-2E7C: Bit serial data interface, signal

BSD is abbr of serial data interface, and the serial data interface is a single-wire data bus with a data transfer rate of 1.2 Kbit/s. The following components are connected to the DME Control Module via a serial data interface:

Generator (depending on the type)
Intelligent battery sensor (depending on the model series)
Electric coolant pump (related to model)
Oil status sensor (related to model)

 

The following data will exchange between the DME/DDE and related components:

Feature request from DME

Identification data sent to DME

System parameter value sent to DME

System trouble information sent to DME

If the component recognizes a fault, it notifies the DME/DDE the fault via the serial data interface. The DME will record the fault in the fault code memory.
The system does not have a detailed description of the fault code, and a brief introduction to the fault details, as shown in the table.

Item	1th Fault Record	Last/Current Fault Record
Engine Speed	0 r/min	0 r/min
Bus KL.87 Voltage	11.48 V	11.58 V
Speed	0 km/h	0 km/h
Engine Control Status	ENG STOP 0-n	ENG STOP 0-n
Mileage	117000 mile	117000 mile
SAE Trouble Code	U119D	U119D
Logistic Counter	40	40
Frequency	2	2

Technician try to clean the trouble code with ISTD (BMW Rheingold ISTA-D 4.12.12 ISTA-P 3.65.0.500 Free download),but it show current and can not clean.

The BSD communication circuit diagram,show as below:

Technician measured the communication voltage ,you need to disconnect the battery sensor ,electric coolant pump,generator and oil status sensor before,then measure the communication voltage between DME to BSD,it showed as 0.02 V.

The communication waveform of the BSD is measured as a straight line with no signal, as shown in Figure 2. The description is that DME does not have any signal voltage output, DME is mulfunction.

In order to verify whether the inference is correct, the same model is found to measure in the same way. The measurement result shows that the BSD communication voltage is 7.9V, and the level of this voltage is affected by the voltage of the vehicle network.

 

Measuring the BSD communication waveform is shown in Figure 3. The DME has a signal voltage for the control unit and a signal waveform, indicating that there is no problem with this DME output control. It also proves that the DME of the faulty vehicle does have a fault.

Troubleshooting: Replace and reprogram the DME,the fault code can be clean directly, the vehicle’s oil measurement function work correctly.