Data Bus Malfunction (Low Speed)
There’s a problem with the communication on the low-speed data bus system.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The vehicle's computers aren’t talking properly over the low-speed data network, which can cause various systems to fail or act up.
What the computer is actually seeing
The control modules expect to receive communication signals within a certain frequency range (usually 1-5 kHz) and voltage level (typically 2.5-3.5 V). When it doesn’t see those signals as expected, it sets U1601.
What a healthy reading looks like
Normal communication signals should have a duty cycle of around 50%, maintaining voltage between 2.5 to 3.5 volts during communication intervals.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connectors for the affected modules. Look for corrosion, loose connections, or broken wires. If found, repair and retest.
- 22. Use a scan tool to check for additional diagnostic trouble codes (DTCs). If related codes are present, diagnose those accordingly.
- 33. Test the communication lines with a multimeter; look for expected voltage and signal patterns. If signals are out of spec, check the related wiring and modules.
- 44. If no issues are found with wiring, consider swapping or reprogramming the BCM or affected module. Re-evaluate the network after any adjustments.
Common causes
- Loose or corroded connectors
- Damaged wiring
- Faulty body control module (BCM) or other control modules
- Issues with the module configuration or programming
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s not ideal to drive with this code as it might disable some vehicle systems, leading to potential safety issues.
Will this code come back after I clear it?
If the underlying issue isn’t fixed, yes, it will likely return after a short time.
Why does this code sometimes pair with U0155?
U0155 indicates a loss of communication with a specific module; it’s common for both to set if the communication network has issues.
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