Dashboard Warning Lights — The Most Common Ones and What to Do When They Come On

Dashboard warning lights are one of the most misunderstood features of a modern vehicle. Some drivers ignore them entirely; others pull over immediately for a light that required no immediate action. Understanding which lights are urgent, which can wait until a service appointment, and which are information-only is useful knowledge for every driver.

Red warning lights — stop or act immediately

Red lights in the majority of vehicles indicate a fault that requires immediate attention. Continuing to drive with a red warning light active risks serious damage or a safety incident.

• Oil pressure warning (oil can symbol) — this is the most urgent light on the dashboard. If the oil pressure drops to the point where this light illuminates while driving, stop the engine immediately and do not restart it. Running an engine with low or absent oil pressure destroys bearings within seconds. Check the oil level; if it is not critically low, do not drive the vehicle until the cause has been diagnosed
• Engine temperature warning (thermometer in water) — the engine is overheating. Stop as soon as safe and allow the engine to cool before investigating. Continuing to drive will cause head gasket or engine failure
• Battery / charging system warning — the charging circuit is not functioning. The battery is powering all electrical systems without being recharged. You have a limited amount of time before the electrical system fails entirely. Drive carefully to the nearest workshop without using non-essential electrical loads
• Brake warning light — can indicate either the handbrake is on (check first) or a fault in the braking system. If the handbrake is released and the light remains, check the brake fluid level. Do not drive until the cause is confirmed

Amber warning lights — investigate promptly

Amber lights generally indicate a fault that should be investigated but does not require pulling over immediately.

• Engine management light (engine outline) — a fault has been detected in the engine management system. The engine will usually continue to run but may be in a reduced-performance limp mode. The fault code stored in the ECU is the starting point for diagnosis. This light should not be ignored for more than a few days
• DPF warning light — on diesel vehicles, the diesel particulate filter requires regeneration. A forced regeneration drive (sustained motorway-speed driving) may resolve it; if the light does not clear after this, the DPF requires investigation
• ABS warning light — the anti-lock brake system has a fault and has been disabled. Standard braking still works, but ABS function is absent. Diagnose before the next MOT
• Airbag / SRS warning light — a fault in the supplemental restraint system. The airbags may not deploy correctly in a collision. This requires diagnosis and is an MOT fail item if the light is active during the test
• TPMS warning (exclamation mark in tyre cross-section) — one or more tyres has low pressure or a sensor fault. Check tyre pressures first; if pressures are correct and the light remains, a TPMS sensor fault is indicated
• Power steering warning — on electric power steering systems, an EPS fault has been detected. Steering will require more effort. Do not ignore

Blue and green lights — information only

Blue lights (main beam active, frost warning) and green lights (indicator active, cruise control active) are informational. They do not indicate a fault.

What Shaw’s does when a warning light is the reason for a visit

Shaw’s reads the fault codes from the relevant control module, reviews the live data from the system that triggered the light, and explains clearly what the fault is, why the light came on, and what the appropriate response is — whether that is a repair, a further investigation, or confirmation that the fault is a known benign sensor issue requiring no immediate action.

Contact Shaw’s about a warning light →

We check it properly. We explain it properly. We do the job properly. You decide what gets done.

Shaw’s Service Station | Kinmel Bay & Rhyl | 01745 353481