Why does the engine fault light go off when stepping on the brake?

[LeLuke]

Engine fault light goes off when stepping on the brake due to wiring issues. Electronic control engine fault diagnosis methods: First external then internal. When the engine malfunctions, first check possible fault locations outside the electronic control system. First simple then complex. Check possible fault locations that can be inspected with simple methods first. If no fault is found through visual inspection and instruments or special tools are required for further inspection, prioritize easier checks. First familiar then unfamiliar. Prioritize fault codes in the electronic control system. Think before acting. Prepare before use. Check the performance of some components in the electronic control system and the condition of electrical circuits. Engine maintenance: Use high-quality engine oil and qualified coolant for engine maintenance. Regularly clean radiator scale, remove engine "carbon deposits," replace the vehicle's "three filters" on time, and maintain reasonable engine speed. The engine is the heart of the vehicle, so maintain good driving habits during daily use.

[GemmaLee]

This issue is a bit tricky. I feel it might be related to a short circuit in the wiring. I've encountered a similar situation before where the brake lights would draw extra power when braking. If the wiring harness for the engine warning light is worn or loose, pressing the brakes could alter the current, causing that light to temporarily go out. It sounds like a temporary reaction, but don't ignore it—this often happens due to aging wires or a faulty relay. I strongly recommend finding a professional mechanic to test the circuit with a multimeter and check for any interference. If left unfixed, it could cause bigger problems during your next drive, like unstable voltage that might damage other components. Safety first, after all.

[StRowan]

Hey, as a seasoned driver with over a decade of experience, I've seen this issue quite a few times. My old car had the same problem - the engine light stayed on but went off when I hit the brakes. Turned out it was due to crossed wiring between the brake light circuit and the warning light system. When braking, the current diversion temporarily turned off the light. This is actually a telltale sign of electrical issues, possibly caused by corroded wiring harness connectors or a failing fuse. My usual first step is replacing a small fuse, and if that doesn't work, straight to the mechanic. Don't try DIY fixes as it might interfere with other safety systems - I've noticed the turn signals sometimes respond slower too when this happens.

[HarleyRose]

A brief analysis suggests this might be caused by voltage instability. Pressing the brake increases the load, causing the fault indicator circuit to lose power and turn off. I recommend checking for poor contact in the brake light switch or relay. Don't delay the repair - fix it early for peace of mind.

[LaGiselle]

I feel quite concerned. This situation often indicates underlying issues, such as unstable alternator output or an aging battery. When you press the brake, the voltage drops, causing the warning light to turn off, but this doesn't mean the problem is gone. Instead, it might worsen engine performance. I suggest you first try starting the car and observe the voltmeter. If the readings fluctuate significantly, it means you need to get it checked. Also, pay attention to keeping the wiring clean to avoid dust interference with signals. Safety should never be compromised.