Inpa Error 159 — [2021]

1. Understanding INPA Error Codes:

INPA (BMW Diagnostic Software) uses a variety of error codes to indicate issues with the vehicle's systems or with the software itself.
Error 159 might not be universally documented, so specific details can depend on the vehicle model, software version, and the operation being performed.

What Causes Error 159?

Error 159 occurs when INPA sends a request to an ECU (e.g., DME, ABS, Airbag module) and does not receive an expected response within the timeout period. Common root causes include:

Incorrect Interface or Cable Settings
- Using a non-compatible K+DCAN or ICOM cable.
- Incorrect COM port settings (must match the cable’s assigned port).
- Wrong baud rate (should be 9600 for older cars, 500k or 1M for newer CAN-based systems).
Software and Driver Mismatch
- Missing or outdated FTDI or CH340 drivers.
- INPA configuration files (EDIBAS.INI, OBD.INI) not pointing to the correct hardware.
- Running INPA without Administrator privileges (Windows blocks direct hardware access).
Vehicle-Specific Issues
- The selected ECU is not present or not functional.
- Ignition is OFF (ECUs require ignition ON for most diagnostics).
- Battery voltage too low (<12V) causing unstable ECU communication.
Hardware Faults
- Broken or badly soldered pins in the OBD2 connector.
- Damaged K-Line or CAN transceiver inside the diagnostic cable.
- Short circuits on the vehicle’s diagnostic bus.

Step 5: Pinout and Wiring Check (for advanced users)

Many E46, E39, E38 models require bridging pins 7 & 8 on the OBD2 connector (K-Line and L-Line).
For CAN vehicles (E90+, E60+), ensure pins 6 (CAN High) and 14 (CAN Low) are connected.
Use a multimeter: K-Line should pulse ~0–12V when ignition ON.

Step 4: Test Basic Communication

Open INPA → E90 (example chassis) → Select ECU → Functional Jobs → F2 (Error Memory).
If Error 159 persists, test using Ediabas Tool32:
- Open Tool32 → File → Load SGBD → Choose DME.IPO → Run connect job.
- A return value of 0 means success; -1 indicates failure.

Advanced: Decoding the IFH-0009 Error Log

If you run the "IFHSrv32" tool (located in C:\EDIABAS\BIN), you can see raw error logs. A typical error 159 log looks like this: [IFH-0009] Timeout error on K-Line (no response from ECU)

But if you see: [IFH-0010] ... – That means a short circuit on the K-Line. [IFH-0003] ... – That means incorrect baud rate (9600 vs 115200). Go back to latency settings. inpa error 159

How to Fix INPA Error 159 (Step by Step)

Frequently Asked Questions

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 (BMW Diagnostic Software) uses a variety of

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.

Step 7: Replace the K+DCAN Firmware (Last Resort)

Some cheap Chinese interfaces come with faulty firmware for the PIC microcontroller. You can re-flash them using MProg (for FTDI-based cables). Download the BMW Standard Tools compatibility firmware (version 1.5 or 1.6). After re-flashing, the interface will correctly handle job termination acknowledgments, eliminating Error 159.