Diagnostic Trouble Code Memory (Section 11)

Diagnostic module (OBDII, N59/1) uses 2 different plug connectors for DTC readout:

• 16-pole diagnostic module (OBD II) generic scan tool connector (X11/22) using a generic scan tool, see Fig 1.
• 38-pole data link connector (X11/4) using the HHT (see section 0). See Fig 2 and Fig 3 .
  Fig 1: Identifying Diagnostic Module Generic Scan Tool Connector (OBD II, X11/22)

  Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
  Fig 2: Connecting Test Equipment, Reading & Erasing Diagnostic Trouble Codes

  Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
  Fig 3: Data Link Connector Pin Identification

  Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

DTC readout using the impulse counter scan tool or via the LED pushbutton switch has been eliminated. During DTC readout, the CHECK ENGINE MIL stays on continuously.

The retained diagnostic trouble code (DTC) memory feature of the diagnostic module has been replaced with DTC memory which is cleared after disconnecting the vehicle's battery.

In case of DTC P0131 and P0133, the exact cause of the fault in oxygen sensor 1 (O2S 1) can be read via MODE 5 with the generic scan tool. To do so, the following codes must be entered in the generic scan tool:

1. DTC P0131
   
   Code JD 4A HEX
2. DTC P0133
   
   Code JD 7E HEX