What causes the EPC light to illuminate and fuel delivery failure in JAC diesel vehicles?
2 Answers
JAC diesel vehicles experiencing EPC light illumination and fuel delivery failure may have the following causes: 1. Air intake system leaks, causing the engine control unit to detect the issue and trigger the EPC warning light. This situation also extends to avoiding removing the engine oil dipstick or opening the oil filler cap while the engine is running. 2. When the EPC light illuminates, use a decoder for fault diagnosis and troubleshooting. If fault code 17550 appears, indicating load recording value below threshold; or both 17550 and 17961 appear, suggesting unreliable signal ratio between height sensor and intake manifold pressure (potentially caused by a failed intake pressure sensor), inspect the electronic throttle body. If excessive dirt is found, clean the throttle body and perform basic setting 01-04-060. 3. Actual issues in components or wiring of the engine's electronic throttle system can generally be identified through conventional electrical testing methods. 4. Other comprehensive factors: Engine oil must be filled strictly according to specifications, as overfilling affects mixture concentration and may cause abnormal EPC activation; similarly, excessively low cylinder compression pressure can also lead to such faults.
That time when I was driving my friend's JAC diesel car, the EPC light suddenly came on, and there was no response even when I floored the accelerator—it just wouldn't accelerate. I quickly pulled over, thinking it must be an issue with the electronic throttle control system. It could be a faulty sensor, like the pedal position sensor or throttle position sensor, clogged with too much carbon buildup or short-circuited. It might also be due to loose wiring harnesses, oxidized connectors, or signal transmission failure. In more severe cases, the ECU (engine control unit) might be malfunctioning, unable to control the fuel supply. Diesel cars often have these sensor issues, and if not fixed promptly, they can easily stall or break down. I've seen similar situations in other cars before—sometimes a simple sensor cleaning can fix it, but it's best to take it to a professional shop to read the fault codes with a diagnostic tool. Don't mess around with it, especially on the highway—it's too dangerous. For safety, it's better not to drive it anymore; call for roadside assistance or have it towed to a 4S shop for inspection. Better to fix a small issue now than risk a major repair later.
