What causes the speed sensor failure in Haval H2?
4 Answers
Haval H2 speed sensor failure is caused by excessive distance between the sensor and the target wheel; short circuit or open circuit in the sensor wiring; or sensor damage. Below is additional information: Symptoms of speed sensor failure: It can prevent the car from starting because the PCM does not receive the engine speed signal and thus does not provide fuel injection or high-voltage ignition. When starting the engine, correct identification of the top dead center position of the first cylinder's compression stroke is required for ignition. The control unit compares the engine speed sensor signal with the Hall sensor signal installed on the camshaft. If the engine control unit does not receive the speed signal, it will cease normal operation. Impact of the sensor on ABS: Moreover, the engine speed sensor significantly affects ABS. ABS adjusts its working state based on wheel speed. If the speed sensor is damaged, the ABS can be considered essentially non-functional.
I've encountered sensor alarms several times while driving. The speed sensor on the Haval H2 is quite prone to issues. Mainly, it's due to loose connectors or corroded interfaces, especially when water splashes onto the chassis. Damaged or short-circuited wiring is also common, as aging wires become brittle and can get worn out during turns. Some owners incorrectly wire additional electronic devices, interfering with normal signals. The most troublesome is when the sensor itself fails, particularly when the magnetic sensing head gets covered in oil sludge or metal shavings, making accurate speed measurement impossible. Once on the highway, I suddenly couldn't accelerate and had to pull over to reconnect the plug before it worked again.
My friend at the auto repair shop told me that the Haval H2 speed sensor error mostly occurs in vehicles that have been driven over 70,000 to 80,000 kilometers. The sensor is installed at the engine-transmission connection point, which is particularly prone to water splashing. If the sealing ring ages, it can directly cause the sensor to fail. When they read the fault codes with a diagnostic tool, they found that in some cars, the signal wheel shared by the crankshaft position sensor and the speed sensor was deformed. If the gap exceeds 2 millimeters, the readings become inaccurate. Wiring issues account for 40% of the repair cases, and haphazard wiring for aftermarket audio systems can cause signal interference. The most troublesome part is that after replacing the new sensor, a crankshaft position learning and matching procedure is required. Some small shops lack the necessary equipment, leading to repeated error reports.
Last week in the owner's group chat, there was an H2 with a wildly fluctuating tachometer. It turned out to be caused by excessive iron powder accumulation on the magnet. The OEM sensor is designed near the clutch housing, and metal shavings that fell in during repairs were attracted by the magnet, affecting the readings. Another member's vehicle experienced poor contact due to oxidized and verdigris-covered connector pins after water exposure. The group now recommends avoiding sensor areas during engine washing. For older vehicles, it's advised to inspect wiring harnesses every 30,000 kilometers, especially since deformed underbody panels can more easily wear through wiring.
