Understanding the On-Board Diagnostics II (OBD2) system in your 2004 Mercedes ML350 is crucial for effective vehicle maintenance and troubleshooting. This guide provides essential information about the OBD2 wiring diagram for your ML350, helping you interpret diagnostic data and address potential issues.
The OBD2 system is standardized across most modern vehicles, including the 2004 Mercedes ML350. It allows mechanics and vehicle owners to access a wealth of information about the car’s performance and identify problems through diagnostic trouble codes (DTCs). Knowing the OBD2 port’s pin configuration is the first step to utilizing diagnostic tools effectively.
Below is a detailed pinout of a standard OBD2 connector, which is applicable to your 2004 Mercedes ML350. This diagram outlines the function of each pin, providing a foundation for understanding how diagnostic communication occurs.
| Pin Number | Pin Name | Description |
|---|---|---|
| 1 | K-Line | Ignition control (EZS), air-conditioner (KLA), PTS, safety systems (Airbag, SRS, AB) and some other |
| 3 | TNA | TD engine rotation speed |
| 4,5 | GND | Ground |
| 6 | CAN-high | CAN-High (including AirBag system in W203, W209, W220, W240, R230, С215 after 2004y) |
| 7 | K-Line | Engine control diagnostic (ME/MSM/CDI) |
| 8 | Ignition,… | |
| 9 | K-Line | ABS, ASR, ESP, ETS, BAS diagnostic |
| 11 | K-Line | Gearbox and other transmission components (EGS, ETC, FTC) |
| 12 | K-Line | All activity module (AAM), Radio (RD), ICS, … |
| 13 | K-Line | AB diagnostic – safety systems |
| 14 | CAN-Low | CAN |
| 15 | K-Line | IC, KI, TAU, LWR diagnostic |
| 16 | +12V | Power |
This table details the function of each pin within the 16-pin OBD2 connector. For your 2004 Mercedes ML350, understanding these pin assignments is crucial when connecting diagnostic scanners or tools. Specifically:
- Pin 4 and 5 (Ground): These pins provide the necessary ground for the OBD2 interface to function correctly.
- Pin 6 (CAN-High) and Pin 14 (CAN-Low): These pins are part of the Controller Area Network (CAN) bus, which is a primary communication protocol in modern vehicles, including your ML350. After 2004, Mercedes-Benz increasingly utilized CAN for diagnostics, especially for systems like the airbag in models listed such as W203, W209, W220, W240, R230, and C215.
- Pins 1, 7, 9, 11, 12, 13, 15 (K-Line): These pins are associated with the K-Line communication protocol. K-Line was a common diagnostic protocol used in Mercedes-Benz vehicles prior to the widespread adoption of CAN. The various K-lines are dedicated to different vehicle systems, such as engine control, ABS, transmission, safety systems, and instrument cluster diagnostics.
- Pin 16 (+12V): This pin provides the power supply (12V) to the diagnostic tool or scanner connected to the OBD2 port.
- Pin 3 (TNA): This pin is used for transmitting the TD engine rotation speed signal, which can be valuable for certain diagnostic procedures.
Knowing these pin assignments allows you to understand the communication pathways within your 2004 Mercedes ML350’s diagnostic system. When using an OBD2 scanner, the tool interfaces with these pins to retrieve data and send commands to the vehicle’s electronic control units (ECUs).
OBD2 Protocol Compatibility for Mercedes-Benz, Including 2004 ML350
The 2004 Mercedes ML350 falls into a transitional period for OBD2 protocols. Vehicles from this era might use a mix of protocols as manufacturers moved towards newer standards. Based on general OBD2 protocol adoption timelines and specific Mercedes-Benz models of this year, the 2004 ML350 is likely to utilize KWP 2000 or ISO 9141 protocols for OBD2 communication.
Here’s a broader compatibility list for various Mercedes-Benz models, which can provide further context for your 2004 ML350:
| Model | Engine | Year (starting from) | OBD-2 Protocol |
|---|---|---|---|
| Mercedes A140 | 1397cc, Gasoline (82HP) | 2004 | ISO 9141 |
| Mercedes A160 | CDI, Diesel (60HP) | 2002 | ISO 9141 |
| 1.7 CDI, Diesel (75HP) | 2002 | ISO 9141 | |
| Mercedes A170 | CDI, Diesel (90HP) | 2003 | ISO 9141 |
| Mercedes A180 | 2, Diesel (80HP) | 2008 | CAN 11bit (500kb) |
| Mercedes A190 | 1.9, Gasoline (125HP) | 2001 | ISO 9141 |
| Mercedes B | 1.7, Gasoline (116HP) | 2005 | CAN 11bit (500kb) |
| 2, Gasoline (136HP) | 2009 | CAN 11bit (500kb) | |
| Mercedes C | 320 cdi, Diesel (224HP) | 2006 | CAN 11bit (500kb) |
| Mercedes C W203 | 2.2, Gasoline (105HP) | 2001 | KWP FAST |
| 200 CDI, Diesel (85HP) | 2002 | ISO 9141 | |
| Mercedes C W209 | v6 3L2, Gasoline (217HP) | 2003 | KWP FAST |
| Mercedes C180 | 1.8, Gasoline (109HP) | 2000 | KWP FAST |
| 2, Gasoline (127HP) | 2001 | KWP FAST | |
| Mercedes C200 | 2.2 CDI, Diesel (116HP) | 2001 | ISO 9141 |
| 2, Diesel (115HP) | 2006 | KWP FAST | |
| 2.0 CDI, Diesel (136HP) | 2008 | CAN 11bit (500kb) | |
| Mercedes C200 coupe | CDi w203, Diesel (122HP) | 2003 | KWP FAST |
| Mercedes C220 | 2.1 CDI, Diesel (143HP) | 2001 | ISO 9141 |
| 2.2 cdi, Diesel (150HP) | 2004 | ISO 9141 | |
| CDI, Diesel (170HP) | 2007 | CAN 11bit (500kb) | |
| Mercedes C240 | 2.4, Gasoline (170HP) | 2003 | ISO 9141 |
| Mercedes C270 | 2.7 CDI, Diesel (170HP) | 2003 | ISO 9141 |
| 2.7 CDI, Diesel (177HP) | 2003 | KWP FAST | |
| Mercedes C320 | V6, Gasoline (218HP) | 2001 | KWP FAST |
| 3.0 V6, Diesel (227HP) | 2006 | CAN 11bit (500kb) | |
| Mercedes Classe A | 1.4, Gasoline (80HP) | 2002 | ISO 9141 |
| Mercedes Classe B | 2.0 CDI, Diesel (109HP) | 2005 | CAN 11bit (500kb) |
| 200 CDI, Diesel (140HP) | 2006 | CAN 11bit (500kb) | |
| Mercedes Classe E | 2.7 CDI, Diesel (177HP) | 2003 | KWP FAST |
| Mercedes CLK | 3.2, Gasoline (218HP) | 1998 | ISO 9141 |
| 270 CDi, Diesel (170HP) | 2002 | ISO 9141 | |
| 2.6 V6, Gasoline (170HP) | 2003 | ISO 9141 | |
| 1.8, Gasoline (170HP) | 2004 | KWP FAST | |
| 220 CDI, Diesel (150HP) | 2008 | KWP FAST | |
| Mercedes CLK230 | 2.3, Gasoline (197HP) | 2000 | KWP FAST |
| Mercedes CLS | 3.5, Gasoline (272HP) | 2005 | CAN 11bit (500kb) |
| 320 CDI, Diesel (240HP) | 2006 | CAN 11bit (500kb) | |
| Mercedes E | 220 CDI, Diesel (163HP) | 2007 | CAN 11bit (500kb) |
| Mercedes E220 | 2.2 CDI, Diesel (160HP) | 2004 | KWP FAST |
| Mercedes E320 | 3, Gasoline (215HP) | 2003 | KWP FAST |
| V6, Gasoline (250HP) | 2004 | KWP FAST | |
| Mercedes ML | 4.3, Gasoline (272HP) | 2000 | ISO 9141 |
| V6 3.5, Gasoline (273HP) | 2006 | CAN 11bit (500kb) | |
| Mercedes ML 270 | 270 CDI, Diesel (163HP) | 2000 | ISO 9141 |
| CDI, Diesel (120HP) | 2001 | ISO 9141 | |
| 270 CDI, Diesel (177HP) | 2002 | ISO 9141 | |
| Mercedes ML 320 | 3.2, Gasoline (218HP) | 1999 | ISO 9141 |
| 3.2, Gasoline (218HP) | 2001 | KWP FAST | |
| Mercedes ML 400 | 4, Diesel (250HP) | 2003 | KWP FAST |
| Mercedes ML 55 amg | 5.4i, Gasoline (350HP) | 2003 | ISO 9141 |
| Mercedes S320 | 3.2 i, Gasoline (224HP) | 1999 | KWP FAST |
| Mercedes S400 | 4.0 cdi, Diesel (250HP) | 2003 | KWP FAST |
| Mercedes SL280 | 2.8, Gasoline (204HP) | 2001 | ISO 9141 |
| Mercedes SLK | 2.0 KomprGasolineor, Gasoline (163HP) | 2000 | KWP FAST |
| 3.5 v6, Gasoline (272HP) | 2004 | CAN 11bit (500kb) | |
| Mercedes SLK170 | 2.3, Gasoline (197HP) | 2001 | KWP FAST |
| Mercedes Sprinter | 316 cdi, Diesel (154HP) | 2001 | ISO 9141 |
| Mercedes Sprinter 316 | 2.1, Diesel (160HP) | 2010 | CAN 11bit (500kb) |
| Mercedes V220 | 2.2 CDI, Diesel (122HP) | 2001 | ISO 9141 |
| Mercedes Viano | 2.2 CDI, Diesel (150HP) | 2005 | KWP FAST |
| Mercedes Vito | cdi, Diesel (80HP) | 2000 | ISO 9141 |
| 2.2 CDI, Diesel (122HP) | 2001 | ISO 9141 | |
| 2.2, Diesel (111HP) | 2004 | KWP FAST | |
| 3.2, Gasoline (190HP) | 2005 | KWP FAST | |
| CDI, Diesel (95HP) | 2007 | KWP FAST | |
| Mercedes-Benz | 280cdi 3 v6, Diesel (188 HP) | 2006 | ISO 9141-2 |
| Mercedes-Benz 203K | C180 Kompressor, Gasoline (141 HP) | 2004 | ISO 14230-4 |
| C180 Kompressor, Gasoline (141 HP) | 2004 | ISO 14230-4 | |
| C180 Kompressor, Gasoline (141 HP) | 2004 | ISO 14230-4 | |
| C180 Kompressor, Gasoline (141 HP) | 2004 | ISO 14230-4 | |
| Mercedes-Benz A – Klasse A190 | Gasoline (124 HP) | 1999 | ISO 9141-2 |
| Mercedes-Benz A 170 | (W169), Gasoline (114 HP) | 2008 | CAN |
| Mercedes-Benz A140 | Gasoline (81 HP) | 1999 | |
| Gasoline (81 HP) | 2000 | ISO 9141-2 | |
| (W168), Gasoline (81 HP) | 2003 | ISO 9141-2 | |
| Mercedes-Benz A150 | Gasoline (94 HP) | 2005 | CAN |
| Mercedes-Benz A160 | Gasoline (113 HP) | 1998 | |
| Gasoline (98 HP) | 2000 | ||
| Gasoline (101 HP) | 2001 | ||
| Gasoline (101 HP) | 2003 | ISO 14230-4, ISO 9141-2 | |
| Gasoline (101 HP) | 2004 | ||
| Gasoline (101 HP) | 2004 | ||
| Mercedes-Benz A170 | CDI, Diesel (94 HP) | 2002 | |
| CDI, Diesel (94 HP) | 2002 | ISO 9141-2 | |
| CDI, Diesel (94 HP) | 2002 | ISO 9141-2 | |
| CDI, Diesel (94 HP) | 2002 | ISO 9141-2 | |
| CDI, Diesel (94 HP) | 2003 | ISO 9141-2 | |
| Gasoline (114 HP) | 2006 | ||
| Mercedes-Benz Actros | MPII Bluetec, Diesel (342 HP) | 2007 | CAN |
| Mercedes-Benz A-Klasse | W168, Diesel (89 HP) | 1998 | |
| Gasoline (101 HP) | 1999 | ||
| Diesel (89 HP) | 2001 | ISO 9141-2 | |
| W168, Gasoline (101 HP) | 2002 | ISO 9141-2 | |
| W168, Gasoline (124 HP) | 2003 | ISO 9141-2 | |
| Mercedes-Benz A-Klasse 140 | W168, Gasoline (81 HP) | 2003 | ISO 14230-4, ISO 9141-2 |
| Mercedes-Benz Atego | 818 Bluetec 4, Diesel (175 HP) | 2007 | CAN |
| Mercedes-Benz B 200 | Turbo, Gasoline (191 HP) | 2006 | |
| Mercedes-Benz B170 | Gasoline (114 HP) | 2007 | CAN |
| Mercedes-Benz b180 | Diesel (145 HP) | 2010 | |
| , Gasoline (114 HP) | 2011 | ||
| Mercedes-Benz C | 2002 | ISO 14230-4, ISO 9141-2 | |
| Mercedes-Benz C 180 | Kompressor, Gasoline (155 HP) | 2007 | CAN |
| Mercedes-Benz C 220 | cdi, Diesel (141 HP) | 2004 | ISO 14230-4, ISO 9141-2 |
| Mercedes-Benz C 240 | Typ 203, Gasoline (168 HP) | 2000 | |
| Mercedes-Benz c180 | Gasoline (161 HP) | 2000 | CAN |
| Mercedes-Benz C180K | Blue Efficiency W204, Gasoline (155 HP) | 2009 | |
| Mercedes-Benz C200 | cdi, Diesel (114 HP) | 2001 | CAN |
| cdi, Diesel (114 HP) | 2002 | – | |
| 2003 | ISO 14230-4, ISO 9141-2 | ||
| Mercedes-Benz C200T | Kompressor, Gasoline (161 HP) | 2001 | |
| Mercedes-Benz c220 | cdi, Diesel (124 HP) | 1998 | |
| cdi, Diesel (148 HP) | 2006 | ISO 14230-4 | |
| cdi, Diesel (148 HP) | 2006 | ISO 14230-4 | |
| cdi, Diesel (148 HP) | 2006 | ISO 14230-4 | |
| Mercedes-Benz C230 | 1998 | ISO 14230-4, ISO 9141-2 | |
| 2000 | ISO 14230-4, ISO 9141-2 | ||
| Mercedes-Benz C320 | CDI, Diesel (222 HP) | 2005 | ISO 14230-4 |
| CDI (W203), Diesel (222 HP) | 2006 | ||
| CDI (W203), Diesel (222 HP) | 2006 | ||
| Mercedes-Benz C350 | CGI, Gasoline (275 HP) | 2008 | |
| Mercedes-Benz CL 500 | W215, Gasoline (302 HP) | 2002 | |
| Mercedes-Benz Class A | 2000 | ISO 14230-4, ISO 9141-2 | |
| Mercedes-Benz CLK 230 | Kompressor, Gasoline (191 HP) | 1999 | ISO 9141-2 |
| Mercedes-Benz CLK 270 | CDI, Diesel (168 HP) | 2003 | ISO 9141-2 |
| Mercedes-Benz CLK 320 | Gasoline (215 HP) | 2002 | ISO 14230-4 |
| Mercedes-Benz CLK 500 | W209 M113, Gasoline (302 HP) | 2003 | |
| Mercedes-Benz cls500 | Gasoline (383 HP) | 2006 | |
| Mercedes-Benz E 200K | Gasoline (161 HP) | 2001 | ISO 14230-4, ISO 9141-2 |
| Mercedes-Benz E 270 | CDI, Diesel (168 HP) | 2003 | ISO 9141-2 |
| Mercedes-Benz E 320 | (W124), Gasoline (223 HP) | 1995 | ISO 9141-2 |
| Mercedes-Benz E200CDI | Diesel (101 HP) | 2004 | KW 2000 VAG |
| Mercedes-Benz E200CGI | Gasoline (182 HP) | 2010 | |
| Mercedes-Benz E220 | CDI T, Diesel (141 HP) | 2000 | ISO 9141-2 |
| Mercedes-Benz E-240 | W211, Gasoline (175 HP) | 2004 | ISO 14230-4 |
| Mercedes-Benz e280 | cdi, Diesel (238 HP) | 2004 | ISO 9141-2 |
| Mercedes-Benz E55AMG | Gasoline (342 HP) | 2003 | ISO 9141-2 |
| Mercedes-Benz E-Klasse | W211, Gasoline (222 HP) | 2002 | |
| Mercedes-Benz G-320CDI | W463, Diesel (222 HP) | 2007 | |
| Mercedes-Benz ML 350 | (w164), Gasoline (269 HP) | 2006 | |
| Mercedes-Benz ML270 | Diesel (161 HP) | 2003 | |
| Mercedes-Benz ML320 | Gasoline (215 HP) | 1999 | |
| Mercedes-Benz ML55 AMG | Gasoline (342 HP) | 2003 | ISO 9141-2 |
| Mercedes-Benz ML55 AMG | Gasoline (342 HP) | 2003 | ISO 9141-2 |
| Mercedes-Benz S203 | 220 CDI, Diesel (141 HP) | 2003 | ISO 14230-4, ISO 9141-2 |
| Mercedes-Benz S211 | Diesel (175 HP) | 2004 | ISO 9141-2 |
| Mercedes-Benz S500, lang | (W220), Gasoline (302 HP) | 2005 | CAN |
| Mercedes-Benz SL350 | Gasoline (242 HP) | 2003 | |
| Mercedes-Benz SL500 | R129, Gasoline (302 HP) | 1999 | ISO 9141-2 |
| Mercedes-Benz SLK | Gasoline (215 HP) | 2000 | |
| Mercedes-Benz SLK 200 | Gasoline (135 HP) | 1998 | |
| Mercedes-Benz SLK 230 | Kompressor FL, Gasoline (195 HP) | 2004 | |
| Mercedes-Benz sprinter | Diesel (108 HP) | 2001 | |
| Mercedes-Benz Sprinter 313 | CDI, Diesel (128 HP) | 2008 | CAN |
| Mercedes-Benz Sprinter 315 | CDI, Diesel (148 HP) | 2007 | CAN |
| Mercedes-Benz Sprinter/NCV3 | Diesel (108 HP) | 2007 | CAN |
| Mercedes-Benz V 220 | CDI, Diesel (121 HP) | 1999 | |
| Mercedes-Benz Vaneo | Gasoline (124 HP) | 2002 | ISO 14230-4, ISO 9141-2 |
| Gasoline (101 HP) | 2003 | ISO 9141-2 | |
| Diesel (90 HP) | 2003 | ISO 9141-2 | |
| 1.9, Gasoline (124 HP) | 2003 | ISO 9141-2 | |
| Mercedes-Benz Viano | 2.2 CDI, Diesel (148 HP) | 2005 | ISO 14230-4 |
| CDI 2.0, Diesel (121 HP) | 2007 | ||
| Mercedes-Benz vito | Diesel (121 HP) | 2003 | ISO 14230-4 |
| Mercedes-Benz w 203 | Diesel (141 HP) | 2003 | ISO 14230-4, ISO 9141-2 |
| Mercedes-Benz W169 | Diesel (108 HP) | 2004 | CAN |
| Gasoline (114 HP) | 2006 | CAN | |
| Mercedes-Benz W202 | C230, Gasoline (148 HP) | 1995 | |
| Mercedes-Benz W203 | Gasoline (128 HP) | 2001 | |
| (C180), Gasoline (128 HP) | 2001 | ||
| C220 CDI, Diesel (148 HP) | 2006 | ||
| Mercedes-Benz w204 | Diesel (242 HP) | 2008 | |
| Mercedes-Benz W211 / NTG | Gasoline (161 HP) | 1995 | ISO 9141-2 |
Note that this list is not 100% complete and is for general guidance.
Referring to the table, while the list contains models and years around 2004, there isn’t a direct entry for the “2004 Mercedes ML350”. However, we can infer based on similar models and the timeframe. The Mercedes-Benz E200CDI (Diesel) from 2004 is listed with KW 2000 VAG, and Mercedes-Benz E-240 (W211) and e280 cdi from 2004 are listed with ISO 14230-4 and ISO 9141-2 respectively. The Mercedes-Benz 203K C180 Kompressor from 2004 is also listed with ISO 14230-4. Furthermore, the Mercedes-Benz C 220 cdi from 2004 is listed with ISO 14230-4, ISO 9141-2.
Considering these entries, it’s highly probable that the 2004 Mercedes ML350 would also utilize ISO 14230-4 (KWP2000) or ISO 9141 protocols. To confirm the exact protocol for your specific 2004 ML350, consulting your vehicle’s owner manual or a Mercedes-Benz service professional is recommended.
Utilizing the OBD2 Port for Diagnostics on Your 2004 ML350
With the OBD2 port and a compatible scanner, you can perform various diagnostic tasks on your 2004 Mercedes ML350:
-
Reading Diagnostic Trouble Codes (DTCs): This is the most common use. DTCs are codes stored by the vehicle’s computer when a system malfunction is detected. These codes pinpoint the area of the problem, such as engine, transmission, ABS, or airbag systems.
-
Clearing DTCs: After addressing the underlying issue, you can use an OBD2 scanner to clear the DTCs and turn off the check engine light or other warning indicators.
-
Reading Live Data Streams: OBD2 scanners can display real-time data from various sensors in your ML350. This live data can include engine speed (RPM), coolant temperature, oxygen sensor readings, and more, aiding in diagnosing intermittent issues or monitoring system performance.
-
Performing Actuator Tests: Some advanced OBD2 scanners allow you to perform actuator tests. These tests can activate specific components, like relays or solenoids, to verify their functionality.
Important Considerations:
- Scanner Compatibility: Ensure your OBD2 scanner is compatible with the OBD2 protocols used by the 2004 Mercedes ML350 (likely ISO 9141 or KWP2000). Many modern scanners are multi-protocol and will automatically detect the correct protocol.
- Professional Assistance: While OBD2 diagnostics can be helpful for DIYers, complex issues may require professional diagnosis and repair. If you are unsure about interpreting diagnostic data or performing repairs, consult a qualified Mercedes-Benz technician.
By understanding the 2004 Mercedes Ml350 Obd2 Wiring Diagram and protocol compatibility, you can effectively use diagnostic tools to maintain your vehicle, troubleshoot problems, and ensure optimal performance. This knowledge empowers you to take a proactive approach to vehicle care and communicate effectively with automotive professionals when needed.
