What does the DEF warning light on JMC mean?

2 Answers
VanLucy
07/24/25 3:17am
JMC's DEF warning light refers to the indicator light for the vehicle's auxiliary water tank. When this light is on, it indicates that the auxiliary water tank is low on water. To resolve the issue, you need to add water to the auxiliary tank immediately. The reasons for the warning light being on include: engine overheating alarm, damaged water temperature sensor, or insufficient antifreeze. Additional information: 1. The auxiliary water tank is located under the driver's seat. Remove the seat cushion and then the square metal plate to see the rectangular plastic box inside. If the vehicle has power steering, there is also a round plastic bucket nearby containing hydraulic oil. 2. If the auxiliary water tank is low on water, it needs to be refilled immediately. If the issue is related to the internal instrument processor, you should take the vehicle to a local 4S store for servicing. The car dashboard is a device that reflects the working conditions of various vehicle systems. 3. The main function of the car's auxiliary water tank is to allow the antifreeze to expand when the engine temperature is high, with some antifreeze flowing into the auxiliary tank through the radiator cap. When the temperature drops and the cooling system pressure becomes negative, the system draws the antifreeze from the auxiliary tank back into the cooling system through the radiator cap.
Was this review help?
3
4
Share
Luke
08/10/25 10:52pm
Last time I drove my Jiangling pickup truck, the dashboard suddenly flashed a DEF light, which left me puzzled at first. Later, I asked a mechanic friend and learned that this is a warning light specific to diesel vehicles, indicating a low level of Diesel Exhaust Fluid (DEF). DEF is a specialized fluid used to clean exhaust emissions, and if not refilled in time, it can trigger the vehicle's protection mechanism and even limit engine power. The solution is simple: find a gas station or auto parts store to buy a bottle of DEF fluid, then open the small tank cap near the trunk and pour it in. For beginners like me, I suggest not panicking when encountering warnings and dealing with them promptly to avoid breaking down on the road. Going through this process also made me pay more attention to vehicle maintenance—now I always check the fluid levels before heading out to prevent similar situations.
Was this review help?
3
1
Share
Expand All
More Forum Discussions

What Causes the Abnormal Noise at the Engine Belt?

Abnormal noise at the engine belt occurs because the belt is slipping on the generator, causing intense friction and vibration between the belt and the pulley, which produces a certain frequency of noise. The belt may be loose or aged. Factors that can lead to belt looseness include improper adjustment of the belt tensioner or insufficient tensioner spring force. In this case, the tension of the belt tensioner should be adjusted. If this doesn't resolve the issue, the tensioner should be replaced. Belt aging mainly refers to the belt gradually hardening and losing elasticity over prolonged use, reducing the friction between the belt and the pulley. Since the main component of the drive belt is rubber, especially in winter, the rubber becomes hard and brittle, reducing the friction coefficient. If the belt is excessively worn, it may also produce a "squeaking" noise.
19
2
Share

How to Operate Car Window Buttons?

Car window buttons can be pressed firmly downward to automatically lower the window completely, or pulled firmly upward to automatically raise it fully. If you want the window to stop at a specific position, gently toggle the button up or down. There is a pressure point inside the mechanism—just try a few times to get the hang of it. For cars equipped with one-touch window control, the window switch has two positions: the first position works like a regular electric window, while the second position allows the window to automatically open or close fully with a single press and release. One-touch window control refers to a system where the car window glass can be fully opened or closed with a single button press. Nowadays, most mid-to-high-end car models come with this feature, primarily for the convenience of drivers and passengers, and to prevent distractions caused by manually operating the windows, thereby improving safety. One-touch windows usually also have an anti-pinch function to avoid the risk of pinching fingers.
5
1
Share

What is the solution to the abnormal noise in the X-Trail's sunroof?

Solution for abnormal noise in the X-Trail's sunroof: The noise is usually caused by friction between the sunroof glass seal and the roof metal panel. Generally, spraying some dashboard wax on the external seal or cleaning the seal thoroughly and applying some hand cream can resolve the noise issue. The X-Trail is a model under Dongfeng Nissan, with body dimensions of 4675mm in length, 1820mm in width, and 1722mm in height. The X-Trail features a multi-link independent rear suspension with a double-loop structure, which increases torsional rigidity by 30% compared to previous models, enhancing straight-line high-speed performance. Combined with the tuned MacPherson independent front suspension and high-speed damping control shock absorbers, the X-Trail not only handles various road conditions with ease but also provides ride comfort comparable to luxury sedans.
9
2
Share

What Causes Engine Piston Slap Noise?

Engine piston slap noise causes: 1. Bent or twisted engine connecting rod deformation; 2. Excessive carbon buildup in the engine leading to increased compression ratio and detonation; 3. Poor engine lubrication conditions causing abnormal friction between pistons and cylinder walls; 4. Incorrect gasoline grade usage resulting in excessive speed that leads to high cylinder pressure, causing piston skirt to impact cylinder walls and produce knocking sounds. Engine piston slap noise refers to abnormal sounds produced by the piston striking the cylinder walls. The determining factor for piston slap lies in the clearance between the piston and cylinder wall. When piston clearance is too large, slapping is likely to occur. The noticeable manifestation is louder knocking sounds when the car engine is cold (due to larger piston clearance), but as engine temperature rises, piston clearance decreases accordingly, and the knocking sound diminishes.
17
3
Share

Where is the cabin air filter located in the Boyue vehicle?

The cabin air filter of the Boyue vehicle is located in the front passenger side, beneath the glove compartment near the center console area. To access it, simply clear out any items from the glove box before proceeding with removal. The Boyue is a model under Geely Auto, with body dimensions measuring 4519mm in length, 1831mm in width, and 1694mm in height, featuring a wheelbase of 2670mm. In terms of exterior design, the Boyue's front fascia adopts Geely's signature "water ripple" grille design. Considering the robust aesthetic required for SUVs, designers reduced the number of grille meshes, resulting in a cleaner overall appearance with more pronounced angular features.
18
1
Share

Does Mineral Engine Oil Need to Be Changed Every Six Months?

Does mineral engine oil need to be changed every six months? Generally, mineral oil can be changed every 5,000 kilometers, while synthetic oil can be extended to 8,000 to 10,000 kilometers. In terms of time, for vehicles that do not travel 5,000 kilometers in six months, it is still advisable to consider changing the oil after six months. Engine oil, motor oil, or engine lubricant is a substance enhanced with additives in base oil, mainly containing anti-wear additives, detergents, dispersants, and multi-grade oil viscosity index improvers. The main functions of engine oil are to reduce friction and wear on moving parts and to remove sludge (one of the functions of dispersants) and varnish (cleaners) from the engine.
18
4
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.