U0140 on Jaguar: How to Diagnose & Fix
Lost Communication with BCM
2 Jaguar models · 2 documented issues · $200-$1,500 repair
U0140 on Jaguar by model: symptoms, diagnosis and fix
The S-TYPE is notorious for electrical gremlins caused by moisture ingress into control modules and poor CAN bus connections. Phantom warning lights, inoperative features, and intermittent faults across multiple systems are common and difficult to diagnose without dealer-level equipment.
Common Symptoms
- Multiple warning lights illuminated simultaneously
- Windows or locks operating erratically
- Instrument cluster errors or flickering
- Intermittent no-start condition
- Features working one day and not the next
How to Fix
Check all module locations for moisture ingress, particularly the driver footwell and trunk. Clean and reseal all CAN bus connectors with dielectric grease. Reprogram affected modules with the latest software. Replace the 12V battery if it is over 4 years old.
Owner tips & cautions
- TipBuy an iCarsoft i930 Jaguar-specific scanner. It reads all Jaguar modules and saves thousands in dealer diagnostic fees. Essential tool for S-TYPE ownership.
The XJ suffers from cascading electrical faults caused by body control module (BCM) software glitches and CAN bus communication errors. Phantom warning lights, inoperative features, and intermittent failures across multiple systems are common, especially after battery disconnection or jump-starting.
Common Symptoms
- Multiple random warning lights illuminated
- Windows or sunroof operating on their own
- Central locking malfunction
- Instrument cluster errors
- Intermittent failure of various electrical accessories
How to Fix
Have the BCM reprogrammed with the latest JLR software at a dealer. Check all ground connections for corrosion, especially the main chassis ground behind the engine. Replace the 12V battery with a genuine Jaguar-spec AGM battery. Avoid jump-starting without a proper battery management system.
Owner tips & cautions
- TipAlways maintain the 12V battery in good condition. A weak battery is the #1 cause of BCM glitches on the XJ. Use a battery tender if the car sits for more than a week.
U0140 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0140 mean on a Jaguar?
U0140 stands for "Lost Communication with BCM." U0140 is a network communication code meaning a module has lost communication with the body control module (BCM) over the vehicle's data bus. The BCM oversees many body and convenience functions — lighting, door locks, windows, wipers, anti-theft, and gateway communications — so losing contact with it can cause a wide range of seemingly unrelated electrical problems and warning lights. This is typically a wiring, connector, power/ground, or bus fault, or a failure of the BCM itself. Because the BCM often acts as a communication hub, this code can appear alongside other 'lost communication' codes. On Jaguar it is documented across 2 models: S-TYPE, XJ.
What are the most common causes of U0140?
The most common causes of U0140 are: Loss of power or ground to the BCM, CAN/data bus wiring damage, short, or open circuit, Corroded, loose, or damaged BCM connectors, Blown fuse feeding the BCM, Failed body control module, Water intrusion or corrosion in the harness, Another module faulting the shared data bus. The specific cause varies by vehicle.
How much does it cost to fix U0140 on a Jaguar?
Published repair estimates on Jaguar range from $200 to $1,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for U0140 on a different make?
View U0140 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.