2022 Hyundai Elantra / Sonata / Santa Fe EPB Warning Light TSB

Hyundai has released Technical Service Bulletin (TSB) 23-01-036H, also known as Service Campaign 990, to address a specific issue affecting certain 2022 Elantra, Sonata, and Santa Fe vehicles. This bulletin details a problem where the Electronic Parking Brake (EPB) warning light may illuminate on the dashboard.

The root cause is identified as brake fluid potentially entering the electrical connector of the Hydraulic Electronic Control Unit (HECU). While the warning light appears, the bulletin notes that the actual performance of the EPB system remains unaffected.

Symptoms

Owners of affected vehicles may observe the following:

• The Electronic Parking Brake (EPB) warning light illuminates on the instrument cluster.
• A Diagnostic Trouble Code (DTC) C1501, indicating an "EPB Switch Failure," may be stored in the vehicle's computer system.

Despite the warning, the functionality of the Electronic Parking Brake is generally not compromised.

Fault codes / DTCs

If your vehicle is experiencing this issue, a diagnostic scan may reveal the following fault code:

Code	Description	Module
C1501	EPB Switch Failure	HECU (Hydraulic Electronic Control Unit)

What the service bulletin says

Hyundai Technical Service Bulletin 23-01-036H outlines a procedure for dealerships to inspect the Hydraulic Electronic Control Unit (HECU) for potential brake fluid intrusion. The primary inspection involves measuring the HECU's "dark current" to determine if it exceeds specified maximum values.

For the 2022 Hyundai Elantra and Sonata, the maximum dark current value is 95 microamperes (µA). For the 2022 Hyundai Santa Fe 2.5L, it is also 95 µA, while the Santa Fe 2.5T has a maximum of 105 µA. If the measured dark current is at or above these thresholds, the HECU, identified by part numbers such as 58910-AB800, 58910-L0100, 58910-S2DA0, or 58910-S2GA0, must be replaced. If the current is below the maximum, no further action is required.

This service campaign is mandatory for affected vehicles before customer retail delivery and whenever they are brought in for any maintenance or repair. Dealers are instructed to use a multimeter (e.g., DT-830D+) to perform the measurement and follow specific steps for documenting the repair with photos.

What to do

If you own a 2022 Hyundai Elantra, Sonata, or Santa Fe and notice the Electronic Parking Brake warning light illuminated, it is advisable to contact your authorized Hyundai dealership. Inform them about the issue and reference Technical Service Bulletin 23-01-036H or Service Campaign 990.

The dealership will perform the necessary inspection of the HECU dark current. If the inspection confirms the issue, they will proceed with the replacement of the Hydraulic Electronic Control Unit to resolve the problem and clear the Hyundai Elantra EPB warning light. This service should be covered under the campaign.

Source: NHTSA ID: 10237179