Controller Area Network CAN-B - Car Logic

1 1 Controller area NetworkCAN507 HO CAN B (ICC)10-28-022 These technical training materials are current as of the date noted on the materials, and may be revised or updated without check for revised or updated help avoid personal injury to you or others, and to avoid damage to the vehicle on which you are working, you must always referto the latest Mercedes-Benz Technical Publication and follow all pertinent instructions when testing, diagnosing or making and descriptions in this training reference are based on preliminary information and may not correspond to the final USversion vehicles. Refer to the official introduction manual and WIS when Mercedes-Benz USA, LLC, 2002 Reproduction by any means or by any information storage and retrieval system or translation in whole or part is not permittedwithout written authorization from Mercedes-Benz USA, LLC or it's by Mercedes-Benz USA, LLCP rinted in U.

2 Explain advantages of CAN networks Explain how CAN networks operate Describe location of CAN connectors Explain CAN diagnosis techniques Provide reference information on other models(reference section at back of handout) 4 What is a CAN System?A CAN system is: A digital communication link between multipleElectronic Control Modules (ECM) A 2 wire, bi-directional communication link with datatransmitted according to priority Message specific addressing5 Advantages Cost Improved immunity to electrical interference Fewer connectors Fewer pins on control modules Weight savings Fewer sensors Improved diagnosis facilities Rapid transmission rates 6 Types of CAN CommunicationMercedes-Benz uses several CAN networks.

3 Dependingon model and year the following may be C - Engine CAN (also known as chassis CAN)Fast communication speeds 125 kbps or 500 kbpsCAN B - Interior CAN (also known as body CAN)Communication speed 83 kbpsInformation from CAN C can be sent to control moduleson the CAN B or vice versa via the Electronic IgnitionSwitch (EIS). The EIS is the only control module* thatcan transfer the messages and is known as CANC ontrol module 1( fuel system)Control module 2( climate control)Control module 3( ignition)Coolant sensor 1 Coolant sensor 2 Coolant sensor 38 CAN BusControl module 1 Sensor 1 Controlmodule 5 Controlmodule 2 Controlmodule 3 Controlmodule 4 Controlmodule 6 CAN B ExampleControlling window from doorwindow switchwindow switchwindow switchwindow switchLF DCMRF DCMRR DCMLR DCM10 CAN High & LowThe CAN wiring consist of 2 wires called CAN High(CAN H) and CAN Low (CAN L).

4 All the control modules are connected in a parallel circuitusing either Z splices or plug connector blocks (X30/_).For the remainder of this presentation and shopmodules, we will concentrate on the CAN B Network asused in W203 / W220).11 CAN H~ ~ CAN-H has a voltage of approx. volts when dormant Rises to base voltage of volts when communicating Data seen as voltage levels going high 12 CAN L~11 volt~ volt CAN-L has a voltage of volts dormant Base voltage drops to volts when active Data seen as voltage level going low 13~11volt~ ~ ~ B High & Low14 Safety ConceptCAN H shorted to ground, cannot communicateCAN L still communicates (single line operation) SignalDoor switchRear SAMEIS WAKE UP !

5 ! / Door open N70 (Overhead Control Panel) EIS is the master of the CAN EIS wakes up the control modules on the CAN16 Tools For Diagnosing CAN BhOhm meterhVolt meterhOscilloscopehCAN B test harnesshSDShWISNote: The red lead is not always the CAN H220 589 00 99 3017W203 CAN B (MY 2001)X30/6N73N70N22A1N72/1N10/1X30/7N10/ 2N32/1N69/1N69/3A40/3N69/4N69/2N32/2N2/7 X30/4A35/1712 CAN H wires are BN/RDCAN L wires are BNexcept where indicatedGN/WTGN1 early lateRDBN2BN/BKBNvia N10/1 Note: Always refer to the wiring diagram for your model and CAN B Connector X30/6h N73 - EISh N72/1 - UCPh A1 - ICMh N22 - AACh N70 - OCPh N10/1 - Front SAM19W203 CAN B Connector X30/7h N10/1 - Front SAMh A40/3 - COMANDh A2 - Radioh N69/1 - DCM-FLh N69/3 - DCM-RLh N10/2 - Rear SAMh N32/1 - ESA-FL20W203 CAN B Connector X30/4h N69/2 - DCM-FRh N69/4 - DCM-RRh N2/7 - SRSh A35/17 - TELE AIDh N32/2 - ESA-FR21 CAN B MalfunctionshShorted CAN BhConstantly active CAN BhIncorrect version coding22 Shorted CAN BWhen both the High and Low CAN B are shorted to ground orpositive no communication is possible between control can happen if: a.

6 Control unit shorted b. Wiring harness shortedHow could we determine if the CAN B is shorted? a. Monitor CAN B voltage out of EIS b. Monitor CAN B oscilloscope pattern out of EIS c. Monitor the DAS (SDS)23 Constantly Active CAN BCAN B needs to go into a dormant state when the ignitionswitch is in the 0 position. EIS is the control unit in charge ofactivation and deactivation of the CAN a control unit in the CAN B keeps sending a signal the EISwill not request the CAN B to go into a dormant can we determine if the CAN B has not gone into adormant state? a. Monitor CAN B activity with an oscilloscope b. Monitor CAN B voltage24 Diagnostic Exercise For CAN BThe following diagnostic exercise involves aW203 with a shorted control CAN BX30/6 (dash)N73N70N22A1N72/1N10/1X30/7 (left)

7 N10/2N32/1N69/1N69/3A40/3N69/4N69/2N32/2 N2/7X30/4A35/1726 Diagnostic Exercise For CAN B27X30/6N73N70N22A1N72/1N10/1X30/7N10/2N 32/1N69/1N69/3A40/3N69/4N69/2N32/2N2/7X3 0/4A35/1728X30/6N73N70N22A1N72/1N10/1X30 /7N10/2N32/1N69/1N69/3A40/3N69/4N69/2N32 /2N2/7X30/4A35/17 Disconnect CAN wire29X30/6N73N70N22A1N72/1N10/1X30/7N10 /2N32/1N69/1N69/3A40/3N69/4N69/2N32/2N2/ 7X30/4A35/17Re-connect CAN wireDisconnect CAN wireRe-connect CAN wires until Network instable again30X30/6N73N70N22A1N72/1N10/1X30/7N1 0/2N32/1N69/1N69/3A40/3N69/4N69/2N32/2N2 /7X30/4A35/1731X30/6N73N70N22A1N72/1N10/ 1X30/7N10/2N32/1N69/1N69/3A40/3N69/4N69/ 2N32/2N2/7X30/4A35/1732 Diagnostic Exercise For CAN BPress the F2 key for a list of control units that the EIS cancommunicate with33 Diagnostic Exercise For CAN B34 Reference Materials for FurtherReadingWIS documents vehicle Network networking (163 as of 9/01) bus system data bus, data bus data data bus data bus data bus, contents, function description35 Additional Information forOther Models36 CAN B Voltages W203, C215 & W220hCAN H active: , dormant: L active: , dormant: B Voltages W202, C208 & W210hCAN H active: , dormant L active: , dormant B on W203 with connector X35/2X30/6N73N70N22A1N72/1N10/1X30/7N10/ 2N32/1N69/1N69/3N69/4N69/2N32/2N2/7X30/4 A35/17A40/3X35/2 Brown andBrown withRed tracer(Vehicles from approx.)

8 06/02)Note: Always refer to the wiring diagram for your model and : Right front sill39W220 CAN BX30/6N73N80N22A1N72/1GN10/7N10/6X30/5A3 7N22/4N32/1N69/1N69/3A40/3N10/8N69/4N69/ 2N62N32/2N25/6N70YX30/4 GWYG reen BandWhite Band Yellow BandWWN88N69/540C215 CAN BX30/6N73N80N22A1N72/1GN10/7N10/6X30/5A3 7N32/1N69/1A40/3N10/8N69/5N62N22/6N32/2N 69/2N70YX30/4 GWYG reen BandWhite BandYellow BandWWN8841 Location of X30 s for C215 & W220X30/6X30/5X30/442 C215 / W220 Connector X30/6hWires with the green band goto N73 (EIS)hWires with the white band goto N10/6 (Left SAM)green bandwhite band43C215 / W220 Connector X30/5hWires with the white band goto N10/6 (Left SAM)hWires with the yellow bandgo to X30/4white bandyellow band44 Control Units Connected to X30/6C215 / W220hN73 - Electronic Ignition SwitchhN80 - Steering Column ModulehN22 - Automatic Air ConditioninghA1 - Instrument ClusterhN72/1 - Upper Control PanelhN10/7 - Right SAMhN10/6 - Left SAM45 Control Units Connected to X30/5C215 / W220hA37 - PSEhA40/3 - COMANDhN22/4 - Rear automatic air conditioninghN32/1 - Electric seat adjustment lefthN69/1 - Door control module 1hN69/3 - Door control module 2hN10/6 - Left SAM46 Control Units Connected to X30/4C215 / W220hN10/8 - Rear SAMhN70 - Overhead control panel (Via N10/8)

9 HN69/2 - Door control module 2hN69/4 - Door control module 4hN62 - ParktronicshN32/2 - Electric seat adjustment righthN25/6 - Electric seat adjustment rearhN88 - Tire pressure monitoringhN69/5 - KeyLess Go47W202, 208, 210 CAN BX30/7 - Right front door sill Electronic Ignition Switch EIS - N73 Signal Acquisition and Actuation Module SAM - N10/1 Door Control Modules DCM s - 1 for each door N69/1-4 Pneumatic System Equipment PSE - A37 Electronic Seat Adjustment ESA s - N32/1&2 Overhead Control Panel OCP - N70 Lower Control Panel LCP - N7248W210 CAN , 208 & 210 CAN B1V2V3V4V5 VCAN HIHigh Sleep Voltage Awake Voltage (CAN Message)0 VCAN LOWLow Sleep Voltage Awake Voltage (CAN Message)50 InteriorEngineNot on CAN BUSN25/6, Rear seat heatermoduleN30/2, Differential lockmoduleG Class (463) Networking51X30/6N73N69/1A1A35/11X30/7N1 0/2N32/1N69/3A40/3N69/4N69/2N32/2X30/4N1 0/1N22N70N72/1 All CAN H wires are redAll CAN L wires are brown except where notedCAN H wire black CAN L wire brownCAN B Diagram for 46352463 CAN B Connector LocationsX30/6 under drivers dashX30/4 and X30/7 in passengerkick panelCAN wires are labeled with a tag onX30/4 & X30/753463 CAN C Connector Location.

10 Right side of center consoleX63/454N52 RVCN10/8 Rear SAMN62 PTSN88 TPCN69/5 KGN82/1 BNSA35/8 Tele AidN10/11 SAM-FRN32/2 ESA-RN70 OCPN69/2 DCM-RN55 SDA1 ICMN80 SCMN69/1 DCM-LN10/10 SAM-FLN22 AACN72 LCPN32/1 ESA-LN3/10 ECMN63/1 DTRN51/2 ABCN15/5 ESMN15/3 ETCN47-5 ESPN73 EISX30/18X30/15X30/16X30/17 CAN- CCAN- BCAN- BCAN- BA73n1 SBCN35/15 MCS-LA2 COMANDA37 PSEA35/16 MCS-RN2/7 SRSX11/4R230 CAN B , CAN C & D2 BCAN CCAN Bnot connected to either CANBrBr / BkBrBr / BkD2B2-wireSBC CANGnGn/WhCAN Bwire colors(exceptwhere noted)Br Br / Rd55 EIS (N73)IC (A1)SCM (N80)DCM-L (N69/1)SAM-FL (N10/10)AAC (N22)LCP (N72)ESA-L (N32/1)X30/15 Inside driver s side door sill(next to X30/18)R230 CAN B Connector X30/15 MCS-L (N35/15)56X30/16 Inside passenger side door sillSAM-FR (N10/11)OCP (N70)DCM-R (N69/2)SD (N55)ESA-R (N32/2)R230 CAN B Connector X30/16 MCS-R (A35/16)57X30/17X30/17 Behind passenger seat, next to SAMRVC (N52)SAM-Rear (N10/8)PTS (N62)TPC (N88)KG (N69/5)BNS (N82/1)TELE AID (A35/8)COMAND (A2)PSE (A37)D2BD2BR230 CAN B Connector X30/1758X30/18 Inside driver s side door sill(next to X30/15)EIS (N73)IC (A1)SCM (N80)ECM (N3/10)DTR (N63/1)ABC (N)