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BMW K+DCAN OBD2 cable pinout#
The BMW K+DCAN cable uses the standard 16-pin OBD2 / J1962 diagnostic connector. It is commonly used with BMW diagnostic software such as INPA, EDIABAS, NCS Expert, WinKFP and ISTA.
The K+DCAN interface supports both older K-Line diagnostics and newer D-CAN communication. For BMW diagnostics, the most important pins are power, ground, K-Line and CAN lines.
OBD2 16-pin connector pinout for BMW K+DCAN#
- Pin 1 — Manufacturer-specific / OEM. On some BMW adapter wiring diagrams this pin may be used for ignition +12V, Terminal 15.
- Pin 2 — SAE J1850 Bus+; not used by BMW K+DCAN.
- Pin 3 — Manufacturer-specific / OEM.
- Pin 4 — Chassis Ground.
- Pin 5 — Signal Ground.
- Pin 6 — CAN High / D-CAN High.
- Pin 7 — K-Line, ISO 9141-2 / ISO 14230.
- Pin 8 — BMW secondary K-Line / manufacturer-specific line. On many K+DCAN cables this pin is connected or disconnected from pin 7 by the cable switch.
- Pin 9 — Manufacturer-specific / OEM. This is not the standard CAN-Low pin.
- Pin 10 — SAE J1850 Bus-; not used by BMW K+DCAN.
- Pin 11 — Manufacturer-specific / OEM.
- Pin 12 — Manufacturer-specific / OEM.
- Pin 13 — Manufacturer-specific / OEM.
- Pin 14 — CAN Low / D-CAN Low.
- Pin 15 — L-Line, optional ISO 9141-2 / ISO 14230 line.
- Pin 16 — Battery Power +12V, Terminal 30.
K+DCAN cable switch: OBD2 pins 7 and 8#
Many BMW K+DCAN cables have a built-in switch. This switch is used to connect or disconnect OBD2 pin 7 and OBD2 pin 8.
- Pins 7 and 8 connected — used for older BMW models that require K-Line access through both diagnostic lines.
- Pins 7 and 8 disconnected — used for newer BMW models that communicate through D-CAN on pins 6 and 14.
If the switch is in the wrong position, the diagnostic software may not connect to the ECU or may only see some modules.
BMW K+DCAN active pins#
For most BMW K+DCAN diagnostic cables, the active OBD2 pins are:
- Pin 4 — Chassis Ground
- Pin 5 — Signal Ground
- Pin 6 — D-CAN High
- Pin 7 — K-Line
- Pin 8 — Secondary K-Line / switch line
- Pin 14 — D-CAN Low
- Pin 16 — Battery +12V
Pins 2 and 10 are used for SAE J1850 communication and are not used by BMW K+DCAN diagnostics.
BMW round 20-pin diagnostic connector pinout#
Older BMW models may use the round 20-pin diagnostic connector under the hood. A 20-pin to 16-pin OBD2 adapter may be required when using a K+DCAN cable on these vehicles.
Common BMW 20-pin diagnostic connector functions:
- Pin 1 — TD / engine speed signal
- Pin 2 — CAN High, where equipped
- Pin 3 — CAN Low, where equipped
- Pin 4 — Shielding / screen
- Pin 7 — Oil service and inspection reset
- Pin 11 — External starter signal, model-dependent
- Pin 12 — Generator / battery indicator, model-dependent
- Pin 14 — Battery +12V, Terminal 30
- Pin 15 — L-Line / RxD diagnostic data line
- Pin 16 — Ignition +12V, Terminal 15
- Pin 17 — K-Line / TxD2 diagnostic data line
- Pin 18 — PGSP / programming line
- Pin 19 — Ground / GND
- Pin 20 — K-Line / TxD diagnostic data line
BMW 20-pin to OBD2 adapter wiring#
A common BMW 20-pin to OBD2 adapter wiring for diagnostic use is:
- OBD2 pin 16 — BMW 20-pin pin 14, Battery +12V
- OBD2 pin 4 — BMW 20-pin pin 19, Ground
- OBD2 pin 5 — BMW 20-pin pin 19, Ground
- OBD2 pin 7 — BMW 20-pin pin 17 and/or pin 20, K-Line
- OBD2 pin 8 — BMW secondary diagnostic line, depending on adapter design
- OBD2 pin 15 — BMW 20-pin pin 15, L-Line, if supported by the adapter and diagnostic interface
Some BMW 20-pin adapters and K+DCAN cables internally bridge K-Line pins to provide access to more modules. If the adapter or cable is wired incorrectly, INPA, ISTA or other BMW diagnostic software may fail to communicate with the vehicle.
Important note#
For BMW K+DCAN diagnostics, do not confuse OBD2 pin 9 with CAN-Low. The standard D-CAN / high-speed CAN pair is:
- Pin 6 — CAN High
- Pin 14 — CAN Low
The K+DCAN switch only affects pins 7 and 8. It does not switch CAN High or CAN Low.
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