Fault in Instrument Cluster Communication
The instrument cluster is not receiving proper communication signals.
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 dashboard is having trouble talking to the rest of the car's computer systems. This could be because of a wiring issue or a problem with the dashboard itself.
What the computer is actually seeing
The instrument cluster expects regular communication pulses at 5V from the control modules. When it doesn't receive these signals, it throws the B1933 code.
What a healthy reading looks like
Normal signal should be between 4.5V to 5.5V with a steady pulse frequency of 1 to 2 Hz during active communication.
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. Visually inspect the instrument cluster wiring harness for damage or corrosion. Check ground connections. Decision: Repair if found bad, if not, go to step 2.
- 22. Use a multimeter to measure the voltage output at the instrument cluster connector with the ignition on. Expected voltage is between 4.5V and 5.5V. Decision: If within range, go to step 3; if not, check wiring and connectors again.
- 33. Check for any technical service bulletins (TSBs) related to the instrument cluster or main computer for software updates. Decision: If an update exists, perform it, otherwise go to step 4.
- 44. Replace the instrument cluster if no communication issues are found in wiring and after verifying the software is up-to-date.
Common causes
- Damaged wiring in the instrument cluster harness.
- Faulty instrument cluster module.
- Poor ground connection at the cluster.
- Software glitch in the vehicle’s main computer.
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate; you can drive but address the issue soon to avoid misreading critical information.
Will this code come back after resetting?
It can return if the underlying issue isn't fixed, especially if it's a wiring fault.
Why does this relate to multiple codes?
Communication errors can lead to multiple components failing to integrate correctly, resulting in several codes.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →