MRS3 - System Overview
The MRS term, meaning Multiple Restraint system is adopted by quite a few Airbag system manufacturers, and this is no exception. This variation is quite sophisticated and complex for an Airbag system having a substantial number of configurable features and options to make it extremely flexible for many application requirements.
SM076 - MRS3 - System Help file
Version 1.22

MRS3 - Known Fitments
Vehicle makes, models and variants known or believed to be using this vehicle system, required diagnostic lead and degree of known compatibility.

Vehicle Make Vehicle Model Vehicle Variant Diagnostic Lead
Rover Commerce >2003 Black OBDII Lead
Rover Streetwise All Models Black OBDII Lead
Rover 25 >2003 Black OBDII Lead
Rover 45 >2003 Black OBDII Lead
Rover 75 >2003 Black OBDII Lead
Rover 75 Tourer >2003 Black OBDII Lead
MG CDV >2003 Black OBDII Lead
MG ZR >2003 Black OBDII Lead
MG ZS >2003 Black OBDII Lead
MG ZT-T >2003 Black OBDII Lead
MG Express >2003 Black OBDII Lead

MRS3 - Physical Details

MRS3 - Pin Outs
Details of the pin usage for the ECU connector.

 
1 Left head airbag suppy - output
2 Left head airbag suppy - output
3 Right head airbag suppy - output
4 Right head airbag suppy - output
5 Ignition supply - input
6 Ground
7 SRS warning lamp
8 Passenger's seat belt switch
9 K-line
10 - 11 Driver's airbag supply
12 Driver's seat belt switch
13 - 14 Passenger's airbag supply
15 Not used
16 - 17 Left side (thorax) airbag - supply
18 - 19 Right side (thorax) airbag - supply
20 Left side crash sensor - input
21 Right side crash sensor - input
22 - 23 Left front pretensioner supply
24 - 25 Right front pretensioner supply
26 - 27 Shorting bar for the left head airbag
28 - 29 Shorting bar for the right head airbag
30 Not used
31 - 32 Shorting bar for warning lamp
33 - 34 Not used
35 - 36 Shorting bar for driver's airbag
37 Not used
38 - 39 Shorting bar for passenger's airbag
40 Not used
41 - 42 Shorting bar for the left side (thorax) airbag
43 - 44 Shorting bar for the right side (thorax) airbag
45 - 46 Rear left pretensioner
47 - 48 Rear right pretensioner
49 - 50 Rear center pretensioner

SM076 - MRS3 - Diagnostic Capabilities (Read Fault Codes)
Reads the fault code memory. The ECU can self detect up to 78 different problems with itself, its wiring and its associated sensors, storing the respective code if it detects any malfunction or reading outside of pre defined acceptable limits. Not all stored faults may cause the fault warning lamp to illuminate.

SM076 - MRS3 - Diagnostic Capabilities (Clear Fault Codes)
Clears the fault code memory.

SM076 - MRS3 - Diagnostic Capabilities (Settings)
Values, configuration settings, and other stored information which can be read from the ECU, edited and then rewritten back. Read settings can also be stored as a standard HTML page for reference. These pages can then later be re loaded and re written back to the ECU. Please note that some values may be read only due to the fact that they are supplied from the ECU’s ROM or are internally calculated.

  • Part number: This is the manufacturer's part number for the ECU.
  • Hardware version: This is the hardware version which denotes the processor and circuit board type.
  • Coding index: This denotes the coding inside the processor for the hardware.
  • Diagnostic index: This is a number that indicates the diagnostic capabilities support level.
  • Bus index: This is a number that indicates the bus communication support level, the vehicle communication buses.
  • Manufacture date: This is the week and year in which the unit was built.
  • Supplier: This is a number which defines the supplier using a standard look up list of supplier ECU manufacturer numbers.
  • Software version: The version on the software currently running on the ECU.
  • Serial number: Unique number assigned to each unit for identification purposes.
  • Programming date: Date which the unit was programmed.
  • Bus type: This index denotes the bus communication support level, the vehicle communication buses.
  • VIN: (SRS DCU VIN) This is the identification number stored in the SRS unit, which is used for comparison with the vehicle VIN