Inpa Error 159 -

Q: Does INPA Error 159 mean my DME (ECU) is dead? A: Rarely. 95% of the time it is a cable or driver issue. Only consider a dead DME if you have tried three different cables and two different laptops, and you have confirmed 12v on Pin 16 and continuity on Pin 7.

Q: Can I use a USB-to-Serial adapter to fix this? A: Yes, if you have an old physical serial port laptop. Native COM ports rarely throw error 159. If you must use a USB adapter, buy a StarTech ICUSB232PRO (FTDI chip).

Q: Why does INPA work for the airbag but not the engine (error 159)? A: The engine (DME) is on a different diagnostic address ($33). The airbag is on $58. If the DME is asleep or the K-Line signal quality is poor, the DME will time out but the airbag module—which is less sensitive—will respond. This still indicates a weak signal issue (latency or cable bridge). inpa error 159

Q: I set latency to 1ms, but Windows resets it to 16ms. Why? A: Some counterfeit chips ignore latency settings. You need to use the FTDI Prog tool to write the latency value directly to the EEPROM of the cable. Or buy a better cable.

INPA Error 159 is a common communication fault encountered when using INPA (Interrogation of Control Units) diagnostic software for BMW vehicles. This error typically appears as: Q: Does INPA Error 159 mean my DME (ECU) is dead

"Error 159: No response from control unit"

or a similar variant indicating a timeout or missing reply from a specific Electronic Control Unit (ECU). INPA Error 159 is a common communication fault

On older cars, the K-Line from the DME to the OBD port can have high resistance due to corroded pins. Also, the 74HC125 or 74HCT125 driver chip inside your K+DCAN cable can overheat and fail partially—passing wake-up signals but failing on high-speed data.

BMW’s K-Line is a shared data wire. Many modules (DME, EGS, ABS, Airbag, IKE) all talk on the same green wire (Pin 7 on the OBD2 port). The Problem: If one module is faulty, crashed, or stuck in a "high" state, it holds the K-Line high (12v), preventing any other module from communicating. INPA tries to wake up the DME, but the dead module is screaming over it. Result: Error 159.

Tool32 (found in C:\EDIABAS\BIN) bypasses INPA’s job scheduler. Open Tool32, load the appropriate .PRG file (e.g., MSV70.PRG for E90 325i). Run a simple job like FS_LESEN (read status). If Tool32 returns valid data but INPA returns Error 159, your INPA installation has corrupt .IPO or *.ENG files.