DIY Convert MB SD Connect C4 OBDII Cable to a DoIP Cable

Purpose of the conversion:

The pinout of both cables is exactly the same except for the 2 pins dedicated just to identify the type of cable. Both MB SD Connect C4 Xentry/DAS, DTS Monaco or Vediamo use the cable identifier, so if it is not recognized as DOIP, some operations will be limited.

Dicalimer:

The tutorial here is for sharing purpose.  Credit to all these contributors @gcs190, @msr, @ BJ from Mhhauto forum. You are at your risk.

There are 2 types of round connectors, some have the letter L and others do not, but the pins used (although change the position of the letters from L to P) are the same.

DOIP cables generally use the letter L, The red pin is A:

convert-sd-c4-obdii-to-doip-cable-1 convert-sd-c4-obdii-to-doip-cable-1 (1)

To make the modification on the cable, we have to work in the area of the round connector, for this we must expose the back:

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Above right in yellow we see the connector U, on its right V, with a resistance of 1200 Omnios and then the hole where W should be

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We have to finish drilling the hole:

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In this case, the partner has removed a pin that was in the connector but is not used (S)

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To place it in the W position:

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Fix it with our preferred adhesive, replace the original resistor between U and V of 1200 Ohms by one of 3.3k and do the same between U and W:

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Here we see how the cable is shown in Vediamo before the modification:

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And here after the modification:

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The companion @msr made the modification taking advantage of an old cable to which in addition to modifying he added the OBD connector and after that he has tested it with Xentry Online
with perfect results updating an Audio / Command DOIP

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This modification could also be done on the side of the male connector (SD Connect) but we would lose the identification of another type of cable unless we used a switch for it.

Here I leave the pinout of both cables in case you need it, the x indicate that the cable is not used and the R that it is a resistance (in the case of U it is zero, that is, there is no resistance)

CABLE_OBDII_SDC_XC (Standart cable OBDII, no DOIP)
CABLE ID 8001

PIN SDconnect/Xentry Connect—— PIN OBD II
===============================================
A (GND)———————— 5
B (KL.15 (Ignition))———– 8
C (VBat)———————– 16
D (K)————————– 1
E (K)————————– 2
F (K)————————– 3
G (K)————————– 11
H (HS-CAN1 H, K)————— 6
J (HS-CAN1 L, K)————— 14
K (K)————————– 7
L (K)————————– 9
M (K)————————– 10
N (HS-CAN2 H, LS-CAN2 H, K)—- 12
P (HS-CAN2 H, LS-CAN2 L, K)—- 13
R (K)————————– 15
S (K13,SWS)——————– x
T (K14,DMC)——————– x
U (Resistor GND)————— R
V (Resistor0)—————— R
W (Resistor1)—————— R
X (K15)———————— x
Y (K16)———————— x
Z (K17)———————— x

CABLE_ID 8001:
Contact U is direct mass.
Contact V must have 1200 Ohms against U.
Contact W must not have continuity against U. (In fact, there is no contact)

CABLE_OBDII_SDC_XC_DOIP (Cable OBDII, DOIP Compatible)
CABLE ID 8016

PIN SDconnect/Xentry Connect —– PIN OBD II
===============================================
A (GND)———————— 5
B (KL15 (Ign.), DoIP Enable)— 8
C (VBat)———————– 16
D (K)————————– 1
E (K)————————– 2
F (Eth Rx+, K)—————– 3
G (Eth Rx-, K)—————– 11
H (HS-CAN1 H, K)————— 6
J (HS-CAN1 L, K)————— 14
K (K)————————– 7
L (K)————————– 9
M (K)————————– 10
N (Eth Tx+, HS/LS-CAN2 H, K)— 12
P (Eth Tx-, HS/LS-CAN2 H, K)— 13
R (K)————————– 15
S (K13,SWS)——————– x
T (K14,DMC)——————– x
U (Resistor GND)————— R
V (Resistor0)—————— R
W (Resistor1)—————— R
X (K15)———————— x
Y (K16)———————— x
Z (K17)———————— x
CABLE_ID 8016
Contact U is direct mass.
Contact V must have 3200 Ohms against U.
Contact W must have 3200 Ohms against U.
Between V and W there must be 6400 ohms (The same resistance cannot be used for both contacts)

Test report:

Successful online programming Mercedes V class 447 Audio/Command with Xentry with hand made DoIP cable according to this tutorial. Mux is Chinese Sdconnect C4 plus (with DoIP support).

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