CAN data bus, function - GF54.00-P-0005F

MODEL 124 with ENGINE 104, 111, 119 (except 104.98)

MODEL 129 with ENGINE 104, 112, 113, 119, 120 (except 104.98)

MODEL 140 with ENGINE 104, 119, 120

MODEL 163 with ENGINE 112, 113

MODEL 170 with ENGINE 111, 112 (except, 112.96)

MODEL 202 with ENGINE 104, 111, 112

MODEL 203 with ENGINE 111, 112 (except, 112.96)

MODEL 208 with ENGINE 111, 112, 113

MODEL 210 with ENGINE 104, 112, 113, 119

MODEL 215 with ENGINE 113, 137 (except 113.99)

MODEL 220 with ENGINE 112, 113, 137 (except, 113.99)

MODEL 230 with ENGINE 112, 113 (except, 113.99)

MODEL 211 with ENGINE 112, 113 (except, 113.99)

MODEL 209 with ENGINE 112, 113

Shown on example of Controller Area Network bus class C (engine compartment) (CAN-C) in model 220 with engine 112, 113 and code (219) Distronic (DTR)

Fig 1: Identifying CAN Data Bus Function

Courtesy of MERCEDES-BENZ USA

Task

Data interchange between the individual control units
Readying sensor signals for several systems
Reducing the number of wires
Improving the electromagnetic compatibility

Design

The data bus consists of a twisted, two-core data line which connects all the participants together in a parallel circuit. The data line lines must not be mixed up (low or high level). The ME-SFI [ME] control unit (N3/10) (except model 124 and model 140), the DAS [FBS] control unit (N73/1) (model 129), the DAS [FBS] radio frequency/infrared control unit (N54/4) (model 129) and the DAS [FBS] radio frequency control unit (N54/3) (model 170) are regarded as terminals as far as bus adaptation is concerned. A terminating resistor of 120 Ω is fitted in each case. Exception: ME-SFI [ME] control unit (N3/10) with engine 120 (each fitted with 240 Ω).

When measuring the resistance on the data line (circuit 15 OFF), the various terminating resistors in the terminals are connected in parallel.

Function

The data are transmitted digitally on the data bus at various intervals. The individual data blocks are defined in a protocol and this also states which data are received or transmitted by a control unit. Each connected control unit is able to transmit or receive data.

The total of the data blocks, the short pause between 2 transmission intervals and further properties of the data bus are checked constantly. Any faults detected are stored.

Vehicles with EIS [EZS] control unit (N73)

In the vehicle a distinction is made between a fast Controller Area Network bus class C (engine compartment) (CAN-C) and Controller Area Network bus class B (interior) (CAN-B) which is 6 times slower. The EIS [EZS] control unit (N73) forms the interface (Gateway) for this. This does not apply to vehicles with a central gateway control unit (N93) (except model 203).

Vehicles with central gateway control unit (N93)

The central gateway control unit forms the interface (Gateway) between the two data buses (N93) (except model 203). The central gateway control unit (N93) serves as the interface for STAR DIAGNOSIS for all model series.

The new control unit must be coded again when exchanging control unit. The control unit can be coded via a menu in the handheld tester (up to 07/99) or via STAR DIAGNOSIS.

CAN data bus, function	Model	GF54.00-P-0005A
Networking, general	Model 202 as of 1.6.97 Model 210 as of 1.3.97 (except 210.081/281) Model 210.081/281	GF54.21-P-9611C
Extended vehicle networking (EVN), function	Model 215, 220 up to 31.8.03	GF00.19-P-0001S
	Model 215, 220 as of 1.9.03	GF00.19-P-0001SX
	Model 203 up to 23.4.04	GF00.19-P-0001PP
	Model 203 as of 24.4.04 up to 30.11.04 except code (494) USA version except code (498) Japanese version	GF00.19-P-0001PM
	Model 203 as of 1.12.04 except code (494) USA version except code (498) Japanese version	GF00.19-P-0001PN
	Model 203 as of 24.4.04 up to 30.11.04 with code (494) USA version	GF00.19-P-0001PMU
	Model 203 as of 1.12.04 with code (494) USA version	GF00.19-P-0001PNU
	Model 203 as of 24.4.04 up to 30.11.04 with code (498) Japanese version	GF00.19-P-0001PMJ
	Model 203 as of 1.12.04 with code (498) Japanese version	GF00.19-P-0001PNJ
	Model 209 up to 31.5.04 except code (491) USA version except code (498) Japanese version	GF00.19-P-0001Q
	Model 209 as of 1.6.04 except code (494) USA version except code (498) Japanese version	GF00.19-P-0001QM
	Model 209 up to 31.5.04 with code (498) Japanese version	GF00.19-P-0001QJ
	Model 209 as of 1.6.04 with code (498) Japanese version	GF00.19-P-0001QMJ
	Model 209 up to 31.5.04 with code (491) USA version	GF00.19-P-0001QU
	Model 209 as of 1.6.04 with code (494) USA version	GF00.19-P-0001QMU
	Model 230 up to 31.5.04 except code (494) USA version except code (498) Japanese version Model 230 up to 30.6.04 with code (494) USA version except code (498) Japanese version	GF00.19-P-0001R
	Model 230 as of 1.6.04 except code (494) USA version except code (498) Japanese version Model 230 as of 1.7.04 with code (494) USA version	GF00.19-P-0001RM
	Model 211.0/2	GF00.19-P-0001T