Jaguar Frequently Asked Questions - Rennology Motor Sport, Chicago

Common Jaguar Problems & FAQ

Check Engine Light or running rough? Here you will find some answers to the most frequently diagnosed Jaguar problems. We do not recommend you assume that the answer here directly relates to your Jaguar. And, you should know that often third parties will misdiagnose a car for what appears to be similar problems or related diagnostic codes.

Diagnosing Jaguar Problems

One of the most common misdiagnosis is where a customer says they need a new catalytic converter because a well known parts store told them they have an O2 sensor code setting off a Check Engine Light! This can be a very expensive and time consuming Jaguar mistake. Accurately diagnosing a Jaguar problem requires more than just reading codes from an onboard computer.

Over the years we have heard and seen first hand the results of bad diagnosis, bad business practices or a simple lack of experience. You can read about the most recent and some of our all time favorites in our Horror Stories Section.

Below you will find answers to some of the more common Jaguar problems and potential solutions. Please be cognizant of the fact that you have one check engine light and hundreds of reasons why it could be triggered.

Common Jaguar Problems and Frequently Asked Questions

OVERHEATING - COOLING FANS INOPERATIVE: The cooling fan module on X-TYPE vehicles may fail under certain circumstances. There are various root causes but the design and quality of the printed circuit board within the cooling fan module are the most significant. The gate used in the circuit is defective causing multiple failure modes, this can result in high engine temperature and overheating due to the cooling fans not operating. The cooling fan assembly was subsequently updated to address this issue.
EXPANSION TANK COOLANT LEAK: You may experience a coolant leak from the engine area. The coolant leak is often caused by the expansion tank bleed tube fracturing where the bleed tube meets the tank. The coolant leak can lead to an engine overheat condition and should be fixed as soon as possible.
HISSING NOISE/DRIVEABILITY ISSUES: Some X-TYPE vehicles may exhibit drivability or hesitation under throttle concerns. You may also experience a hissing noise from under the hood. The concern is often caused by a vacuum leak from the O-ring seal on the Intake Manifold Tuning (IMT) valve. The O-ring that fails is now available separately to avoid the need to replace the entire valve system.
FUEL SYSTEM - DRIVEABILITY/STARTING ISSUES: Jaguars often experience problems both mechanically and electrically with the fuel delivery system. This can cause the car to stop and seem like a low fuel issue even when the tank is full. The problem can also cause issues when fueling the car or cause a noisy fuel pump. The problem is associated with a communication issue between the instrument cluster and the fuel sending units.
CHECK ENGINE LIGHT - V6 ENGINE: There is a known common problem associated with certain vehicles fitted with spark plugs that produce a low ohm value. Commonly, DTC codes 3041 or 3141 are produced and cannot be cleared. Replacing the spark plugs usually solves this problem.
KNOCK FROM CRANKSHAFT AREA: You may experience a 'dull knock' noise coming from the engine
between 1000 to 2300 RPM on light acceleration. This is commonly mis-diagnosed as a bearing failure, but it is quite common for the eccentric motion of the number 2 main crankshaft to cause this problem. The noise is transmitted through the engine mount and Jaguar has a replacement mount that specifically controls the sound. Check this updated engine mount first before tackling the bearings.
AIR CONDITIONING SYSTEM NOT COOLING SUFFICIENTLY: There are many reasons for the failure of an A/C system. However, a common issue on Jaguars is the degradation of control valve operation, preventing the system from delivering full functional potential. Of course it is important to ensure the integrity of the system before under taking this repair, however, replacement of the control valve will usually return improved cooling capacity.
DIFFICULTY SELECTING TRANSMISSION RANGES: Some X-TYPE vehicles with automatic transmissions commonly experience difficulty in select a transmission range, or the message 'GEARBOX FAULT'
flashing on the message center. This is will commonly cause the vehicle to run in limp-home mode. The solution is often a reset of the J-Gate or on older vehicle will be the replacement of the J-Gate system