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.