What it means
The Information Center is present on the data bus but the values it reports are implausible — out of range, frozen, or failing the checksum or rolling-count check. The receiving modules reject the data. Driver-display content may be wrong or missing. Causes include a faulty sensor feeding the module, internal computation errors, a software or calibration mismatch after a repair, or bus interference corrupting the frames.
How it works
The Instrument Panel Cluster displays driver information and can send status data to other vehicle modules. U0423 sets when a receiving module rejects data from the cluster as implausible; the code does not by itself prove that the display hardware has failed.
Common causes
Most likely first.
- Head unit internal fault
- CAN corruption causing checksum errors
- Gateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules and record freeze-frame and communication codes to see which modules reject cluster data and whether other network faults are present.
- Check whether gauges, warning indicators, or displayed information are missing, frozen, or inconsistent with how the vehicle is operating.
- Inspect the cluster connector and nearby network wiring for looseness, corrosion, or damage, including signs of recent dashboard work.
- Check cluster power and ground circuits to the manufacturer's specification and confirm that relevant inputs are plausible.
- Test CAN communication and gateway routing using vehicle service information, and check for software or configuration mismatches after cluster or module replacement.
- Consider cluster repair or replacement only after its power, inputs, network wiring, and configuration have been verified.
Common fixes
- Secure or repair the cluster connector or damaged network wiring.
- Correct a faulty input that is causing implausible cluster data.
- Repair gateway routing or configuration issues.
- Apply an applicable cluster software or calibration update.
- Repair or replace the cluster if its supply and network circuits test correctly but it continues to send invalid data.
Can I keep driving?
If the speedometer, warning lamps, or other safety-related displays are unreliable, avoid driving until you can confirm speed and vehicle warnings by a reliable means. Stop if you cannot safely monitor the vehicle.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.