Progressing from the World War ll Jeep, since the SUVs launch in 1986, the Jeep Wrangler is now in its fourth generation. The Jeep Wrangler dashboard warning lights illustrate the various symbols that may illuminate on your instrument cluster.
Along with a description of each symbol, the appropriate action to take will follow, based on the Jeep’s recommendations. The warning/indicator lights will illuminate in the instrument panel together with a dedicated message and/or acoustic alert when applicable.
Warning lights are divided into red, yellow and green categories, with red indicating urgent attention, yellow indicating an issue that requires attention as soon as possible and green indicating a system that’s been activated.
Jeep Wrangler Red Warning Lights
A red warning light indicates a fault or safety issue that must be looked into immediately.
Airbag / Supplemental Restraint System
As a bulb check, the Jeep Wrangler airbag warning light will illuminate for around 4 to 8 seconds, then switch off. If it stays on, it’s an indication of a airbag and/or supplemental restraint systems fault. Some of the reasons that can cause the airbag light to come on include:
- Crash detection sensor fault
- Clock spring
- Cabling and connectors dislodged under front seats
- Seat belt buckle problems
Vehicle Brake System
This warning light monitors various brake functions, including brake fluid level and parking brake application. If the brake light remains lit, first ensure the parking brake is properly released. If the brake light still remains lit, check that the brake fluid is up to recommended levels.
If the brake light remains on when the parking brake has been disengaged, and the fluid level is at the full mark on the master cylinder reservoir, it indicates a possible problem with:
- Hydraulic brake system
- Brake Booster
If it’s a problem with the brake booster, you’ll notice a pulsating feeling when braking due to the ABS pump operating. If the brake light remains lit, it’s advised that you discontinue driving and have the vehicle brakes serviced immediately.
Vehicle Charging System
The red battery warning light saying on or coming on while driving means there’s a problem with the electric charging system. If there’s not enough electricity being generated to power the vehicle components, for example if the alternator has failed, the engine is likely to stall once the battery has become exhausted of power. See why is my car battery warning light on for further information.
If driving, turn off any electrical systems that are not essential and make your way to a safe location or a vehicle workshop if close by. Common reasons for battery warning light include:
- Alternator fault
- Drive belts loose or broken
- Broken electrical connection / circuit
- Old, failing battery
Electric Power Steering
The Jeep Wrangler is equipped with electro-hydraulic power steering which means an electric pump pressurizes the hydraulic fluid in the steering system. Common reasons for the power steering warning light to come on include:
- Hydraulic fluid pressure / leak
- Electric fault
Extreme steering maneuvers, such as excessive steering while attempting to park, may cause the electrically driven pump to reduce or stop power steering assistance in order to prevent damage to the system. This is a fail-safe system that engages if the system becomes hot and will resume operation once cooled.
Electronic Throttle Control (ETC)
The Jeep Wrangler red lightening bolt warning light means that the Electronic Throttle Control (ETC) is malfunctioning. This ETC warning light will either stay on or flash depending on the nature of the fault. Stopping the vehicle and switching the ignition off, then back on can often resolve the issue.
If the light remains constantly lit, the vehicle is usually driveable, but requires servicing asap. If the light continues to flash, the problem is more urgent and requires immediate attention. In this situation, the vehicle may enter reduced engine performance mode. You may also experience a rough idle or engine stall. Worst case scenario, the vehicle may require towing.
The illumination of the ETC warning light means there’s a problem with the electronic throttle control, which replaced the mechanical throttle. Due to the ETC communications being sent via sensors rather than cables, it’s an indication that the throttle has lost communication with the gas pedal. In some instances, a electronic throttle control system reset may work. To reset the Jeep Wrangler ETC warning light:
- Turn the ignition key to the on position but do not start the engine.
- Once all the warning lights have switched off, slowly press the gas pedal all the way to the floor.
- Then, slowly release the gas pedal until it is all the way back up at the rest position.
- Turn the ignition key to the off position.
- Start the engine and test the throttle by see if the engine will throttle up.
If the ETC reset does not work, it may be a fault with the throttle body, for example the electronic throttle control module, electrical wiring issue, or a faulty sensor.
Engine Coolant Temperature
This red warning light illuminates on the Jeep Wrangler’s dashboard warning that the engine coolant temperature is too high. A single audible alert will also sound. If the temperature reaches a dangerous level, the audible alert will continuously sound for 4 minutes.
If the engine coolant temperature warning light comes on while driving, pull off the road and stop the vehicle. If the air conditioning system is on, switch it off, turn the temperature control to maximum heat, shift the transmission into neutral and idle the engine. If the engine temperature does not return to normal, switch off the engine. For further information, see red engine coolant warning light on or flashing.
The red oil pressure warning light must not be mistaken for low oil level. Low oil pressure means that certain part of the engine may not be sufficiently lubricated, which can cause significant damage.
If the low oil pressure warning light comes on while you’re driving, safely pull off the road and switch off the engine. Low levels of engine oil can result in low oil pressure. Check oil levels and top up if required. However, if the oil pressure light remains lit, even after adding oil, switch off the engine and do not continue driving.
This red warning light indicates that the engine oil temperature is high. As the temperature of engine oil increases, viscosity drops and the engine may be at risk of damage due to a lack of lubrication.
If the high engine oil temperature warning light comes on while driving, pull off the road and stop the engine as soon as possible. For possible reasons why this warning light is illuminating, see oil temperature warning light.
This red warning light indicates that the Jeep Wrangler’s transmission fluid temperature is high. This may occur when the transmission is working particularly hard, such as towing heavy loads.
If the warning light comes on, pull off the road, shift the transmission into neutral or park and keep the engine running at idle. Once the tranny fluid temperature has cooled and the warning light goes off, you can continue your journey.
The Jeep Wrangler red security light will flash at a fast rate for around 15 second when the security is arming itself. The security light will then flash slowly when the system is armed.
Issues regarding a continuously flashing security light, even when the system is disarmed are common. In this situation, try replacing the battery in the key fob, try an alternative fob or disconnecting the vehicle’s battery.
Jeep Wrangler Yellow Warning Lights
A yellow warning light indicates a minor fault or vehicle maintenance issue. A yellow light may also illuminate if a system has been disabled, when by default, it is enabled.
ABS Warning Light
The ABS system (Anti-lock Braking) prevents wheel lockage during harsh braking, therefore allowing the driver the ability to steer the vehicle away from a potential collision.
The ABS system is an extension of the vehicle’s brakes, but operates independently, so if the ABS malfunctions, the vehicle’s brake will operate as normal. Some of the problems associated with ABS failure include wheel speed sensors, ABS module, brake booster (vacuum pump).
ESC Warning Light
This warning light will indicate when the Electronic Stability Control (ESC) system is active. When ESC is operating, the light will flicker or flash. If there’s a fault, it remain steady lit.
ESC is standard on all new vehicles and helps to reduce understeer, oversteer and to increase tire traction when accelerating. One of the most common reasons for an ESC is a damaged wheel speed sensor.
ESC is on by default at each ignition cycle. Though it is recommended to keep it on at all times, if the vehicle becomes stuck in snow, mud etc, it may prove beneficial to temporarily switch off ESC. For more information, see What ESC is in Cars and How Does ESC Work in Cars.
Engine Check Warning Light
The Jeep Wrangler engine warning light illuminates due to the onboard diagnostic system finding a fault within the automatic transmission or engine. There are many possible components that can cause the engine warning light from poor quality fuel, loose fuel filler caps, engine and transmission fault, all the way through to catalytic converter faults.
To help with fault finding, use diagnostic tools to scan for fault codes. A fault code is usually logged whenever the engine warning light comes on. Diagnostic tools read these codes and can benefit by telling you where the fault is.
You can usually continue to drive the vehicle if the engine warning light is on. In some situations, the engine may go into reduced performance mode to help protect the vehicle. If the engine light begins to flash, it can indicate engine misfire, which can cause damage. Reduce speed and engine load immediately. Prolonged driving with the engine light on may result poor fuel economy, increased emissions and damage.
For more information about the common reasons for the check engine warning light to come on, how to scan for Diagnostic Trouble Codes and what to do when the engine warning light comes on, see reasons why the engine warning light is on.
SERV 4WD Warning Light
The Jeep Wrangler SERV 4WD warning light means that the vehicle’s 4WD system is not functioning correctly and requires servicing. While the SERV 4WD warning light is on. you’ll not be able to use the vehicle in 4WD mode and the vehicle will remain in 2WD. Check to ensure all fused are secure and seated correctly.
Service FCW Warning Light
The Jeep Wrangler Forward Collision Warning (FCW) system provides the driver with audible warnings, visual warnings (within the instrument cluster display), and may apply a haptic warning in the form of a brake jerk, to warn the driver when it detects a potential frontal collision.
To ensure full functionality of the FCW system, always ensure the forward-facing camera (in front of the rear view mirror) area on the windshield is kept clean and the radar on the vehicle’s front grille.
If you receive the FCW along with a Service FCW warning message, the system has a malfunction and requires a service. This can sometimes be due to the camera sensor overheating, particularly if the vehicle has been parked in direct sunlight. If there’s a fault with the FCW or ACC system, the FCW OFF warning light may display.
Stop / Start Warning Light
This warning light indicates a fault with the vehicle’s automatic engine stop start system. Versions of the Jeep Wrangler that are equipped with the automatic engine stop start system are fitted with two batteries. The secondary battery used for the stop start system is located behind the wheel well for the front passenger wheel.
Other than a fault with the system, prior to engine shutdown, the system checks for various safety and comfort conditions. If the criteria is not met, auto stop will be unavailable. Some of the reasons why the Jeep Wrangler auto stop is unavailable include:
- Driver’s seat belt is not buckled.
- Outside temperature is less than 10°F (–12°C) or more than 109°F (43°C).
- Inside cabin temperature is greatly different to that set on the Auto HVAC.
- HVAC is set to full defrost mode.
- The engine has not yet reached optimal operating temperature.
- Battery is discharges (see above).
- Driver’s door or the hood is open.
- Transfer case is in 4L or N (Neutral).
- Vehicle is at high altitude.
- Vehicle is on a steep grade.
- Forward Gear is engaged.
- Steering angle is beyond threshold.
Cruise Control Warning Light
This warning light indicates a fault with cruise control system. Cruise control uses the forward-facing camera located in front of the rear view mirror and the radar located in the vehicle’s front grille. Ensure these areas are kept clear and clean.
Sway Bar Warning Light
The sway bar text along with an exclamation point means there’s a fault with the electronic stabilizer/sway bar. Check fuses. A common fault is related to the sway bar actuator. The sway bar warning light without the exclamation point illuminates when the sway bar has been disconnected.
Tire Pressure Warning Light
The Jeep Wrangler tire pressure monitoring system makes use of sensors, one located in each tire. The warning light comes on when one or more tires becomes underinflated.
The warning light will flash for around one minute, then stay on if there’s a problem with the tire pressure monitoring system (TPMS). Common causes of a flashing tire pressure light include:
- Damaged sensor (often caused when changing wheels or tires)
- Exhausted sensor battery
- Aftermarket tires or wheels in use
- Aftermarket tire sealant has been used
- A wheel if fitted that does not contain a sensor
Inflating Your Tires
Tire pressures should be checked and adjusted when cold. Adjust tire pressure in accordance with the cold tire pressure label inside the driver’s door. When filling warm tires, in order to turn off the tire pressure warning light, the tire pressure may need to be increased up to an additional 4 psi (28 kPa) above the recommended cold placard pressure.
After driving the vehicle for around 20 minutes and at speeds of 15 mph and above, the TPMS will automatically update and the tire pressure light will switch off.
4H Warning Light
The 4H warning light comes on to alert the driver that their Jeep Wrangler is in four-wheel drive (4WD) high range mode. This means that the front and rear driveshafts are locked together, forcing the front and rear wheels to rotate at the same speed.
4L Warning Light
The 4L warning light comes on to alert the driver that their Jeep Wrangler is in four-wheel drive (4WD) low range mode. As with 4H, the front and rear driveshafts are mechanically locked together, forcing the front and rear wheels to rotate at the same speed.
Four-wheel drive low range provides greater levels of traction and maximum pulling power for driving on loose, slippery surfaces. In 4L, you must not exceed 25 mph.
4H Part Time Warning Light
The 4H Part Time warning light comes on to alert the driver that their Jeep Wrangler is in four-wheel drive (4WD) high range, part time mode. What does the Jeep Wrangler 4H part time mean?
4H part time means that the rear and front driveshafts are mechanically locked and no differentiation is allowed between the front and rear axles. This means 4H part-time can be used on low traction surfaces (paved roads covered in snow or ice) or off-road, but cannot be used on dry, high-traction roads. 4H part time cannot be used on all road surfaces, hence the term ‘part time’.
This is unlike a full-time 4×4 system, or ‘4H AUTO’ which provides power to all four wheels but shifts the power between the front and rear axles as needed. As such, this type of system can be used on any road surface, full time.
Axle Locker Fault Warning Light
The Jeep Wrangler axle locker fault warning light illuminates when the front and/or rear axle locker has a malfunction. This axle lock fault light with exclamation point can often be attributed to a component in the rear axle.
When the front and rear axles have been locked with out a fault, the front and rear axle lock warning light illuminates. If only the rear axle has been locked, the warning light displaying a lock on the rear axle will illuminate.
ACC Fault Warning Light
This warning light illuminates when there’s a problem with the Jeep Wrangler’s Adaptive Cruise Control (ACC). You may also see the message ‘Service Required’.
Due to the Forward Collision Alert (FCA) system sharing many components, the FCA OFF warning light may also illuminate. This fault can occur due to the sensor being dirty or require calibration.
AdBlue Warning Light
For diesel versions of the Jeep Wrangler, this warning light comes on when AdBlue (UREA) levels are low. Fill the AdBlue tank as soon as possible with at least 1.3 gallons (5 liters) of AdBlue. If the remaining AdBlue range in the tank is zero, you may need to wait two minutes before starting the vehicle.
Water in Fuel Warning Light
When this warning light comes on, it means there’s water in the fuel filter. Trace amounts of water are typically found in diesel fuel. To prevent damage, a fuel filter is used to separate the water from the fuel before the fuel enters the engine. This warning light comes on when the water in the fuel filter requires draining. If the warning light comes on along with an audible alert, stop using the vehicle and drain the water.
The best access to the water drain valve is from under the vehicle, as the fuel/water separator housing is located inside the left frame rail in front of the fuel tank. If necessary remove the fuel filter protective cover to access the water drain valve.