C1604: How to Diagnose & Fix — Manufacturer-Specific Chassis Code (Hyundai/Kia: ECU Hardware Error; Nissan: EPS Torque Sensor)

On early-build 2021 Seltos (SP2) the Electric Power Steering module logs DTC C160404 during its start-up diagnostic self-check and illuminates the steering warning light. In most cases the hardware is fine — the module's judgment logic is over-sensitive during the power-up check, particularly when battery voltage sags at cranking. Kia addressed it with bulletin CHA110 / campaign SA466, an EPS ECU reflash titled 'SP2 EPS MIL ON DTC (C160404) JUDGMENT LOGIC IMPROVEMENT'. Because the fault can appear as a hard warning light, owners are frequently quoted a full EPS rack replacement when a reflash is the actual repair.

Rio owners have reported Forward Collision-Avoidance Assist warnings, disabled AEB/FCA messages, and occasional false collision alerts even in normal driving. Problems are often linked to the front camera or radar alignment, windshield replacement, sensor obstruction, or software sensitivity. Because the system is part of the active safety suite, repeated faults reduce driver-assistance functionality and can create uncertainty about whether emergency braking is available.

Owners have documented intermittent failures of the forward collision warning, lane-keeping, and related ADAS functions, including dashboard messages that the front camera or safety systems are unavailable. Some complaints involve false alerts in clear weather, while others describe the systems disabling themselves after startup or while driving. These issues are often linked to camera alignment, sensor contamination, software logic, or wiring/connectivity problems rather than a mechanical brake fault.

The Hydraulic Electronic Control Unit (HECU/ABS module) can develop an internal electrical short (fluid leakage plus localized PCB melting was found in retrieved units), producing excessive current that can cause an engine-compartment fire while parked or driving. NHTSA recall 23V-652 covers 349,309 2011-2013 Souls equipped with Electronic Stability Control, part of the broader Kia/Hyundai 'park outside' fire-risk campaign. Owners were told to park outside and away from structures until repaired.

An electrical short circuit can develop inside the Anti-lock Brake System (ABS) hydraulic control module. Because the module is always powered, the short can cause an engine-compartment fire whether the vehicle is parked or being driven, even with the ignition off. Genesis recalled certain 2019-2021 G70 vehicles under NHTSA campaign 21V-161 (Genesis recall 007G); owners were told to park the car outside and away from structures until repaired. This is part of the broader Hyundai/Genesis ABS-fire recall family. The remedy installs a fuse in the ABS module wiring to prevent the short from igniting a fire.