What is the reason for the HAVAL H6 hill descent control failure?
4 Answers
HAVAL H6 hill descent control failure is caused by faults in the PT-CAN related circuits or a node, and virtual connections in the gateway internal circuits leading to low network voltage. The specific details are as follows: Faults in the PT-CAN related circuits or a node: Using a fault detector, the electronic parking brake control module (EPB) stored one current fault code: U111281 ESP CAN signal failure. The body stability control module (ESP) 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 other modules stored fault codes. Analyzing the fault codes, it is inferred that there is a fault in the PT-CAN related circuits or a node. Virtual connections in the gateway internal circuits leading to low network voltage: When HDC is activated and the vehicle enters a steep slope, engine braking itself can provide a considerable degree of deceleration effect without the risk of wheel lock-up. When the slope is too steep and engine braking is insufficient to maintain the speed limit, HDC can use the ABS system to reduce the increasing speed, maintaining a stable and safe downhill speed. If the driver needs to steer to avoid obstacles during the downhill process, the HDC system will detect this and further reduce the speed limit to 6.4km/h to ensure full control of the vehicle.
I once encountered a malfunction with the Hill Descent Control (HDC) system while driving my Haval H6 on mountain roads. The system suddenly stopped automatically controlling the speed on a steep slope, which made me a bit nervous. Later, at the repair shop, they found that the wheel speed sensor was clogged with mud. This feature primarily relies on sensors to determine vehicle speed and slope angle. If the sensors have poor contact or the wiring is chewed by rodents, the signal won't reach the control module, causing the system to fail. Additionally, uneven tire wear can lead to discrepancies in the signals read by the ABS module, which can also trigger a malfunction. It's best to regularly clean the dirt around the chassis sensors, especially after driving on muddy roads—washing the car promptly is crucial. This malfunction is something to take seriously. Last time I experienced a failure on a winding mountain road, I had to rely on manual braking to slowly descend, which was quite dangerous.
I've studied the Hill Descent Control (HDC) system on SUVs like the Haval H6. When it reports a fault, there's an 80% chance it's an issue with the electronic control unit. The core of this system relies on the ABS pump and actuators to regulate braking force. If the slope sensor or lateral accelerometer fails, the ECU can't receive gradient data and won't activate. Additionally, aging/short circuits in the control module circuitry or outdated software versions can easily cause system freezes. I once used a diagnostic tool to check fault codes and found voltage instability can trigger system misjudgment, especially when the battery is nearing end-of-life. I recommend having technicians check the system firmware version during each maintenance service, and avoid parking in waterlogged areas - moisture exposure can easily fry the circuit boards.
I think the most common cause of the Hill Descent Control failure in the Haval H6 is issues with the braking system. If the brake pads are worn out or there are air bubbles in the brake fluid, the ABS pump can't build enough pressure to control the speed. Once, after driving through water, I found this function wasn't working, and later discovered that the brake fluid had absorbed moisture and vaporized. Also, leaking shock absorbers causing errors in the vehicle height sensor can affect the descent control system. Don't try to tough it out—once the system fails, the car can easily roll downhill. It's best to promptly visit a 4S shop to replace the brake fluid or check the vacuum booster.
