PROJEKT36 · WIRING

Diagnostic connector

The round 20-pin plug under the bonnet: what each pin carries and the wire colour behind it. Useful when building or checking a K-line cable.

Standard petrol E36 from the 1998 BMW wiring manual. On a phone, scroll the diagram sideways.

projekt36.com/wiring/diagnostic-connector/

SW blackRT redGN greenBL blueGE yellowBR brownWS white GN/SW = green with black stripe supply / ground of a part shown elsewhere

Diagnosis connector X6002

2.5 RT terminal 30 0.5 BR engine ground X6454 0.5 GN/WS fuse F26 0.5 WS/VI control units (DME, EGS, ABS, airbag, …) 0.5 WS/VI DME (M43 / M44) 0.5 WS/GE DME, EGS, ZKE, EWS 0.5 WS/GN DME pin 60, EGS pin 60 0.5 SW DME TD output 0.5 SW/WS cluster X17 pin 2 0.5 WS/GN cluster X17 pin 15 0.5 BL alternator D+ 0.5 SW/GR A/C compressor line 0.5 SW/BL A/C compressor relay line 0.5 SW/RT fan relay line X6002 Diagnosis connector diagnosis connector D100, 20-pin 14 Battery + (30) 19 Ground (31) 16 Ignition on (15) 20 TxD diagnosis line 17 TxD II (four-cylinder) 15 RxD diagnosis line 18 Programming line (PGSP) 1 TD engine speed 6 Road speed (TACHO A) 7 Service interval reset (SI) 12 Charge lamp (61 / D+) 8 A/C compressor 9 A/C compressor delay 10 Auxiliary fan

How it works

The round 20-pin connector under the bonnet is where BMW testers (and K-line cables with a 20-pin adapter) talk to the control units. Pins 14, 19 and 16 give the tester battery, ground and ignition.

Most units share the TxD line on pin 20; RxD on pin 15 wakes them up. The four-cylinder DME has its own line on pin 17.

Check on your car

  • The function and colour of each pin are from BMW's pin table; where the less common lines (8, 9, 10, 12) end up is not drawn on the diagnostic link pages.

Redrawn from BMW ETM 0670.5 diagnostic link (05/99), standard petrol E36 (316i–328i); diesel and M3 parts are left out. Not covered: pins 5, 11 and 13 are not used; pins 2, 3 and 4 are the M3 CAN lines.

Reading the wire codes

BMW labels every wire with its size and colour, for example 2.5 SW/GE: 2.5 mm², black (schwarz) with a yellow (gelb) stripe. Connectors are numbered X…, followed by the pin. The wires in these diagrams are drawn at relative thickness, so the 25 mm² battery cable stands out from a 0.35 mm² signal wire.

Codes used here: SW = black, RT = red, GN = green, BL = blue, GE = yellow, BR = brown, WS = white.