This guide will discuss common problems that cause the Jaguar check engine light to stay on and how to diagnose the problem yourself.
What does it mean when Jaguar check engine light stays on
When the check engine light on a Jaguar stays on even after you start the engine, it means the On-Board Diagnostic (OBD) system has detected a problem with the engine, transmission, or Evaporative Emission Control System (EVAP).
The problem can be from several issues ranging from a loose gas cap to worn spark plugs, faulty ignition coil, oxygen sensor which may be malfunctioning, a catalytic converter that can be clogged, or the mass airflow sensor may be dirty.
These are common problems that can trigger the check engine light on a 1996 and newer Jaguar, including XE, XF, XJ, E-PACE, F-PACE, or F-TYPE, etc. To find out why the check engine light is on in your Jaguar, read the fault codes with an OBD-II scanner.
How to Read Jaguar Check Engine Fault Codes
For this procedure, a diagnostic scanner is needed. In this demonstration, we used a Launch Creader VII multi-system scanner, but any OBD-II scanner will be able to read related fault codes.
- Locate the diagnostic port under the dashboard.
- Connect your OBD-II scanner and turn on the ignition.
- Turn on your OBD-II scanner and select Jaguar from the main menu.
- Select your model.
- Select the Powertrain Control Module.
- Scroll down to Read Codes.
- Select Read Codes and write down all the codes that come up.
Research each cod that comes up. Learn what each code means and what are the possible causes. Some codes are easy and straightforward to fix, while others may require further troubleshooting.
Common causes that trigger Jaguar check engine light.
Bad spark plugs can cause misfires, which the engine management system will detect. Another cause would be bad spark plug wires or high resistance due to age. In either case, the replacement of either the spark plugs or spark plug wires will be the solution.
Loose fuel tank cap
It causes fuel fume leaks that the onboard system will detect, causing a lit CEL. There have also been cases where a full tank sets off error codes in the evaporative system, also causing the Jaguar check engine light to come on.
A broken catalytic converter will cause the CEL to light. Note that catalytic converters are mandated in the U.S. to be warrantied for 8 years or 80,000 miles. If this is indeed the component at fault, then replacement should not cost the owner if it is within the warranty period.
Measures the amount of unburnt fuel in your engine exhaust. A malfunctioning sensor can trigger the CEL. While reasonably sturdy, O2 sensors do fail, and you need to replace them as soon as possible. Broken O2 sensors increase fuel consumption noticeably.
Mass airflow sensor
A blocked or faulty airflow sensor will trigger the check engine light. A problem with this sensor will also increase fuel consumption, affect performance, and increase emissions.
Faulty ignition coils will cause a misfire, which can cause rough idling and poor engine performance. If left unrepaired for too long, this condition will damage the catalytic converter.
A stuck thermostat will give erroneous temperature readings. The temperature readings may not be within the expected range of the coolant sensor, and a lit CEL will be the result.
A leak in the system will cause the CEL to turn on. This will also cause a lean condition that can damage the engine if it is run hard.
Exhaust Gas Recirculation (EGR) system can also trigger the CEL. What happens is that one of the seals in the system hardens. This loss of flexibility can cause an air leak, which will trigger the CEL.
Jaguar Check Engine Light On / Restricted performance mode
A flashing check engine light denotes a critical fault. As a safety measure, the ECU defaults to limp mode so that the driver can get to a dealer, service shop, or another safe place. The engine power is reduced, the engine may shake, which is due to the engine misfiring. Continuing to drive the car for a long will result in catalytic converter damage and needing possible replacement.
There are many possible causes for a blinking CEL. It can be that a sensor has failed or an ignition coil is causing a misfire. Problems with the spark plugs, ignition coils, MAF sensor, EGR valve, fuel injectors, the engine itself, or rarely, the ECU, can cause a flashing check engine light. A blinking CEL has also been reported to occur after an engine wash or when the spark plug wells become flooded with oil or water.
The only way to determine what is at fault when you have a blinking CEL is to read the codes thrown by the ECU.
What to do when Jaguar CEL turns on
- Check gas cap - this is a common cause for a CEL turning on. Sensors will detect a gas fume leak, resulting in a lit CEL. The fix for this is ensuring that the gas cap is fully seated (at least 3 clicks of the cap when tightening). Note that it will take several ignition cycles before the CEL will turn off.
- Check engine oil level - an unseated dipstick or low oil level can trigger Jaguar CEL.
- Coolant temp - coolant temperature will be indicated by the temperature gauge. In this case, the CEL will have lit because the sensor reads the coolant as too hot or too cold. This is usually caused by a stuck thermostat. It is worthy to note that some of the newer Jaguars use Ford-derived engines, and it may be possible to find a more reliable thermostat from a Ford.
- Monitor performance - if you notice that your Jaguar is performing sluggishly, then you may have a clogged catalytic converter. Of course, a bad ignition coil or another fault may be causing the engine to run in safe or limp home mode. Only by reading the codes will you get a better idea of what is causing poor engine performance.
- Read the OBD codes - since the OBD (on-board diagnostics) port is standard in all modern cars, investing in an OBD2 scanner is highly recommended. You can buy a dedicated reader that plugs directly into the OBD port. Or you can buy Bluetooth-enabled transmitters that will interface with your smartphone or tablet, where you can display the error codes.
It must also be reiterated that a blinking check engine light on your Jaguar denotes a critical fault. Try to get to a service area within five miles and have your car checked. In case the CEL is just lit and not blinking, you should still have the error codes read as soon as possible.