What Causes the Hill Descent Control Malfunction Light to Illuminate?

[OBethany]

Here are the relevant reasons for the malfunction light illumination: Node failure: There is a fault in the PT-CAN related wiring or a certain node. Using a fault detection tool, the electronic parking brake control module (EPB) stored one current fault code: "U111281-ESP-CAN signal failure"; the electronic stability program (ESP) module also stored one current fault code: "U100104-CAN passive error"; the engine control module (ECM) stored two historical fault codes: "U01018-Lost communication with TCU" and "U012687-Lost communication with SAS"; no fault codes were stored in other modules. Analyzing the fault codes, it is inferred that there is a fault in the PT-CAN related wiring or a certain node. Gateway internal fault: A loose connection in the gateway's internal circuit causes low network voltage. Measuring the battery voltage, the voltage when the ignition switch is off is 12.6V, the voltage when starting the engine is 10.9V, and the charging voltage is 14.3V, indicating the battery is normal. Based on repair experience, it was decided to first check the network voltage of the SAS (safety airbag module). Disconnecting the SAS wiring connector, the voltage on terminal 2 (CAN-H) was measured at 2.73V, and the voltage on terminal 3 (CAN-L) was 2.31V, which is normal.

[JuneDella]

Last time I drove on a mountain road, this light also came on, so I quickly pulled over to a safe area to check. Mainly these three issues: the sensor was covered in mud, causing the system to shut down due to excessive wheel speed difference; the brake temperature was too high, triggering protection; or the electronic module got wet and short-circuited. I remember that time my tire grooves were clogged with mud, so I rinsed them clean with a hose and the light went off when I got back on the road. If the light stays on after washing the car, you might want to check if the gray connector under the steering wheel is loose.

[LaZoe]

The yellow triangle light with an arrow typically indicates the vehicle stability system is malfunctioning. There are three common causes: First, wheel speed sensor signals may go haywire after rain, causing the system to receive incorrect data and disable functions. Second, transfer case fluid overheating triggers protection - older vehicles especially need fluid condition checks. Third, electronic parking brake wiring issues - when helping my cousin troubleshoot, we found his modified reverse light wiring was pinching the brake lines. If hill descent control fails, stay calm and manually shift to lower gears for more stable speed control.

[VanPaisley]

Don't rush to restart when the light comes on, check these areas first: Have you changed tires recently? A diameter difference of over 3mm between new and old tires can interfere with wheel speed data; Modified pedal position? Poor cable routing may compress sensor wiring; Aggressive undercarriage washing at car washes may cause connector water seepage. Once at a 4S shop, I watched a technician troubleshoot - the diagnostic tool revealed a steering angle sensor calibration offset, resolved with a 5-minute recalibration.