2015 VOLKSWAGEN GOLF GTI check engine light

WARNING
Working on the batteries or the electrical system in your vehicle can cause serious acid burns, fires, explosions, or electrical shocks. Always read and heed the following WARNINGS and safety precautions before working on the batteries or the electrical system.
x Before working on the electrical system, always switch off the ignition and all electrical consumers and disconnect the negative (-) cable from the standard 12 Volt battery.
x When you change a light bulb, always switch off the light first.
x Always keep children away from battery acid and vehicle batteries in general.
x Always wear eye protection. Never let battery acid or lead particles come into contact with your eyes, skin, or clothing.
x Sulfuric battery acid is very corrosive. It can burn unprotected skin and cause blindness. Always wear protective gloves and eye protection. To reduce your risk of injury, never tilt the batteries, as this could spill acid through the vents and burn you.
x If you get battery acid in your eyes or on your skin, immediately rinse with cold water for several minutes and then get immediate medical attention. If you swallow any battery acid, get medical attention immediately.
x When disconnecting the batteries from the vehicle electrical system, always disconnect the negative cable (-) first and then the positive cable (+).
x Always switch off all electrical consumers before reconnecting 12 Volt batteries. Reconnect the plus cable (+) first and then the negative cable (-). Never reverse the polarity of the connections. This could cause a fire.
x A highly explosive mixture of gases is given off when the battery is being charged.
x Do not smoke and avoid fires, sparks, and open flames when working. Never create sparks or electrostatic charges when handling cables and electrical equipment. Never short circuit the battery terminals. High-energy sparks can cause serious personal injury.
x Never use or attempt to charge a damaged or frozen battery, or a battery that was frozen but has thawed. Charging a frozen or thawed battery could cause explosions and chemical burns! Replace damaged or frozen vehicle batteries immediately. A dead battery can freeze at temperatures around +32 °F (0 °C).
x If the battery has a vent line or tube, make sure that it is properly connected to the battery.
WARNING
California Proposition 65 Warning
x Battery posts, terminals, and related accessories contain lead and lead components, chemicals known to the State of California to cause cancer and reproductive harm. Wash your hands after handling.
NOTICE
x Do not expose the vehicle battery to direct sunlight for an extended period of time as ultraviolet rays may damage the battery housing.
x If the vehicle is left standing in the cold for a long time, protect the vehicle battery from freezing. A battery will be permanently damaged by freezing.
Emergency starting and starting the engine with a very weak vehicle battery or after the vehicle battery has been replaced may change or delete system settings (including time, date, personal convenience settings, and programming). Check the settings and correct as necessary once the vehicle battery has built up a sufficient charge.

Check the electrolyte level of the battery regularly if the vehicle has high mileage (km), in places with a warm climate, and if the vehicle has an old battery. Otherwise the vehicle battery does not require maintenance.
Preparations
x Prepare the vehicle for work in the engine compartment ⇒ Working in the engine compartment.
x Open the engine hood ⇒ .
Opening and closing the battery cover
To open, fold the cover to the side in the direction of the arrow ⇒ fig. 159.
To close, fold the cover against the direction of the arrow.
Checking the vehicle battery acid level
x If the lighting conditions are poor, use a flashlight so that you can clearly see the battery acid level indicator and tell what color it is. Never use an open flame or an unprotected light source.
x The round battery window (“acid level indicator”) on the top of the battery changes color, depending on the battery's electrolyte level.

Color Action
Light yellow or colorless Battery electrolyte level is too low. The vehicle battery may need to be replaced. Have it checked by an authorized Volkswagen dealer or an authorized Volkswagen Service Facility.
Black Battery electrolyte level is satisfactory.

WARNING
Working on the batteries can cause serious acid burns, explosion, or electrical shock.
x Always wear eye protection and protective gloves.
x Sulfuric battery acid is very corrosive. It can burn unprotected skin and cause blindness. Always wear protective gloves and eye protection.
x Never tilt the vehicle battery. Acid could spill out of the battery vents and burn you.
x Never open a vehicle battery.
x If you get battery acid in your eyes or on your skin, immediately rinse with cold water for several minutes and then get immediate medical attention.
x If you swallow any battery acid, get medical attention immediately.
Charging, replacing, disconnecting, and connecting the vehicle battery

Replacing the vehicle battery
The battery in your vehicle is specially developed for its location, with special dimensions and safety features. Before buying a new battery, ask an authorized Volkswagen dealer or authorized Volkswagen Service Facility what batteries are suitable with regard to electro-magnetic compatibility, dimensions, required maintenance, performance, and safety specifications. Have the battery replaced by an authorized Volkswagen dealer or an authorized Volkswagen Service Facility.
Only use maintenance-free vehicle batteries meeting standards TL 825 06 and VW 7 50 73. These standards must date from July 2012 or later.
Disconnecting the vehicle battery
If the battery must be disconnected from the vehicle's electrical system, note the following:
x Switch off all electrical systems and devices and the ignition.
x Unlock the vehicle before disconnecting the battery; otherwise the alarm system will go off.
x First disconnect the negative cable (-) and then the positive cable (+) ⇒ .
Connecting the vehicle battery
x Prior to reconnecting the battery, switch off all electrical systems and devices and the ignition.
x Connect the positive cable (+) first and then the negative cable (-) ⇒ .
After the battery is connected and the ignition is switched on, different indicator lights may light up. They should go out after you drive a short distance at 10–12 mph (15–20 km/h). If the indicator lights do not go out, contact an authorized Volkswagen dealer or an authorized Volkswagen Service Facility and have the vehicle checked.
If the battery was disconnected for a long time, the next scheduled service may not be correctly
calculated and displayed ⇒ Instrument cluster. The maximum permissible service and maintenance
intervals are shown in the ⇒ Booklet Warranty and Maintenance.
Vehicles with Keyless Access
If the ignition will not start after reconnecting the vehicle battery, lock the vehicle from the outside and
unlock it again ⇒ Unlocking or locking the vehicle with Keyless Access. Then try to start the ignition again. If the ignition cannot be switched on, contact an authorized Volkswagen dealer, an authorized Volkswagen Service Facility, or another qualified workshop for assistance.
Automatic electrical load deactivation
If the vehicle battery drain is high, the intelligent onboard electrical system management automatically takes steps to help prevent battery drain.
x The idle speed is increased so that the alternator provides more power.
x The power to devices that consume a lot of electricity is cut back or switched off completely.
x When the engine is started, the power supply to the 12 Volt sockets is temporarily interrupted.
The onboard electrical system management cannot always keep the battery from being drained. For example, the battery will drain if the engine is not running, but the ignition is switched on or the parking lights are left on for a long time when parked.
What drains the vehicle battery?
x Long periods when the engine is not running, especially when the ignition is on.
x Using electrical systems or devices when the engine is switched off.
x Leaving the vehicle unlocked for several days when not in use.
x The selector lever is left for a long period of time in any position other than Park (P) when the
ignition is switched off ⇒ Automatic transmission: Selector lever.

Lights up Possible cause Proper response
B Engine control/monitoring system malfunction (engine Malfunction Indicator Light - MIL)
Ease off the accelerator. Carefully drive to the nearest authorized Volkswagen dealer or authorized Volkswagen Service Facility. Have engine checked.


Flashes Possible cause Proper response
B Misfire, which can damage the catalytic converter.
Ease off the accelerator. Carefully drive to the nearest authorized Volkswagen dealer or authorized Volkswagen Service Facility. Have engine checked.

When the ignition is switched on, several warning and indicator lights come on briefly for a function check. They go out after a few seconds.
NOTICE
Failure to heed warning lights or text WARNINGS can result in vehicle damage.
As long as the indicator lights B or %0# are on, expect engine malfunctions, increased fuel consumption, and loss of engine efficiency.
Catalytic converter

Obey all legal requirements regarding protecting a broken-down vehicle. For example, turning on the emergency flashers and wearing a safety vest are mandatory in many countries.
Checklist
For your own safety and that of your passengers, carry out the following steps in the order listed
⇒ :
1. Park the vehicle at a safe distance from traffic and on a suitable surface ⇒ .
2. Switch on emergency flashers by pressing the  button ⇒ fig. 163.
3. Apply the parking brake to help prevent the vehicle from moving ⇒ Braking and parking.
4. Shift the transmission into Park (P) (automatic) or Neutral (manual only) ⇒ Shifting.
5. Stop the engine and remove the key from the ignition switch ⇒ Starting and stopping the engine.
6. Have all passengers exit and go to a safe location away from moving traffic, such as behind a guard rail.
7. Take all vehicle keys with you when leaving your vehicle.
8. Set up a warning triangle or other warning device in order to alert other motorists and cyclists.
9. Let the engine cool down and get expert assistance if necessary.
If the emergency flashers are on, use the turn signal lever to indicate a direction or lane change, for example when the vehicle is being towed. This temporarily interrupts the emergency flashers.
Switch on the emergency flashers when:
x Traffic suddenly slows down or stops in front of you to warn those approaching from behind.
x In any emergency situation.
x If the vehicle breaks down.
x When being towed.
Always obey traffic laws that govern the use of emergency flashers where you are driving.
If the emergency flashers are not working, a different method – as permitted by law – must be used to alert other motorists and cyclists to the breakdown.
WARNING
Disregarding the safety-related checklist may lead to accidents and serious personal injuries.
x Always review and follow the checklist. Follow accepted safety practices and use common sense.
WARNING
The vehicle exhaust system and the catalytic converter get very hot. They can cause fires and serious personal injury.
x Never park where parts of the hot exhaust system or catalytic converter could ignite flammable materials, such as dry grass, brush, leaves, spilled fuel, etc.
NOTICE
To help prevent damage to the vehicle if you should have to push it a short distance by hand, never push against spoilers, lights, body panels, windows, or similar parts. Concentrating