Telematics Control Unit

TCU DTC Database

Complete diagnostic reference for JLR Telematics, SOS Emergency, and InControl systems. Search and filter through all TCU-related diagnostic trouble codes.

25 DTC Codes All JLR Models InControl & SOS
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What is TCU?

The Telematics Control Unit manages connected services including emergency SOS calls, InControl remote features, and vehicle tracking.

Emergency Call System
InControl App Features
GPS & Vehicle Tracking
WiFi Hotspot
Understanding TCU

What is the Telematics Control Unit?

The central hub for all wireless communication and connectivity features in modern JLR vehicles

The Telematics Control Unit (TCU) is a critical electronic control module in modern Jaguar Land Rover vehicles that serves as the central hub for all wireless communication and connectivity features.

Located typically behind the dashboard or in the roof console area, the TCU integrates cellular (3G/4G/LTE), GPS, and Bluetooth technologies to enable a wide range of connected vehicle services. It acts as the vehicle's "smartphone," constantly communicating with JLR's backend servers and the owner's mobile device.

The TCU contains an internal, non-serviceable backup battery that maintains emergency call functionality even if the main 12V vehicle battery is disconnected. This is a critical safety feature mandated by eCall regulations in many markets.

Without a Functioning TCU

Your JLR vehicle will lose access to InControl Remote services, emergency call capability, navigation updates, WiFi hotspot, and over-the-air updates. While the vehicle will still drive normally, you'll see "SOS System Inactive" or "SOS Limited Functionality" warnings.

Emergency Call (eCall)

Automatically contacts emergency services in a collision, transmitting location and crash data.

4G/LTE Connectivity

Provides WiFi hotspot functionality and enables over-the-air software updates.

GPS Tracking

Real-time vehicle location for InControl Remote, navigation, and stolen vehicle tracking.

Remote Control

Remote locking/unlocking, climate control, and vehicle status via smartphone app.

Security Services

Remote immobilization, geofencing alerts, and intrusion notifications.

Concierge Services

Access to JLR's premium assistance via the SOS/bCall buttons.

Visual Reference

What Do These Modules Look Like?

Visual identification guide for TCU, RFA, and BCM modules found in Jaguar Land Rover vehicles

TCU Module

Telematics Control Unit

TCU Telematics Control Unit Module JLR

Cellular & GPS: Provides 3G/4G/LTE connectivity

InControl Services: Remote features and tracking

Location: Behind dashboard or roof console

SOS Function: Emergency call capability

RFA Module

Remote Function Actuator

RFA JLR Remote Function Actuator Module

Keyless entry and remote functions

Behind dashboard or trunk area

RF 315/433 MHz & UWB

BCM Module

Body Control Module

BCM Body Control Module JLR

Central locking & body electronics

Communicates with RFA

Under dashboard or engine bay

Pro Tip: Module Identification

Always verify the module part number before ordering replacements. Use diagnostic tools like Lock50 or JLR SDD to read module information via OBD-II port. Each module has a unique part number printed on its label that corresponds to specific vehicle models and production years. For TCU modules, check generation (Gen 1-4) to ensure compatibility with your vehicle's cellular network technology.

Hardware Reference

TCU Generations & Part Numbers

Complete reference for all JLR Telematics Control Unit versions from 2012 to present

G1

TCU Gen 1

2012-2015
3G UMTS

Part Numbers

FX73-14G370-xx JX73-14G370-xx

Affected Models

Range Rover L405 (13-15MY) Range Rover Sport L494 (14-15MY) Discovery 4 (14-15MY)

Notes: First generation telematics with basic connectivity

G2

TCU Gen 2

2015-2017
3G/4G LTE

Part Numbers

HK83-14G370-xx JK83-14G370-xx

Affected Models

Range Rover L405 (15-17MY) Range Rover Sport L494 (15-17MY) Discovery 5 L462 (17MY) Evoque L538 (15-17MY) Discovery Sport L550 (15-17MY)

Notes: Common water ingress issues, internal backup battery failures

G3

TCU Gen 3

2017-2020
4G LTE Cat-4

Part Numbers

LR110668 LR111537 LR111916

Affected Models

Range Rover L405 (18-20MY) Range Rover Sport L494 (18-20MY) Range Rover Velar L560 (18-20MY) Discovery 5 L462 (18-20MY) Evoque L538 (19-20MY) Discovery Sport L550 (19-20MY)

Notes: Improved reliability, better backup battery management (U2109-09 common on new vehicles)

G4

TCU Gen 4

2020+
4G LTE Cat-6 / 5G Ready

Part Numbers

LR136646 LR140282 LR145893

Affected Models

Defender L663 (20+MY) New Range Rover L460 (22+MY) New Range Rover Sport L461 (23+MY) Discovery Sport L550 (20+MY) Evoque L551 (20+MY)

Notes: Latest generation with enhanced security and 5G preparedness

Troubleshooting

Common TCU Issues & Fixes

Quick reference for the most frequently encountered TCU problems and their solutions

Internal Backup Battery Failure

Related DTC U2109-09
Fix

Requires TCU replacement - battery not serviceable. Run vehicle for 60 minutes to charge on new install.

Water Ingress / Corrosion

Related DTCs
B1179-04 U0001-87
Fix

Locate and repair water source before TCU replacement. Check roof drains and antenna seals.

Parasitic Battery Drain

Related DTCs
B117C-04 P0560-04
Fix

TCU not sleeping properly. Check for internal short (8+ amps draw). Replace TCU if excessive.

No Cellular Signal

Related DTC B1177-04
Fix

Check antenna connections, verify in good signal area, may require TCU replacement.

SOS System Limited Functionality

Related DTCs Multiple DTCs
Fix

Check crash sensor circuit, SOS button wiring, microphone/speaker circuits, and TCU power supply.

Service Reference

Important Service Notes

Critical information for technicians working with JLR Telematics Control Units

Programming Required

All replacement TCUs must be programmed and configured with vehicle VIN using JLR SDD/Pathfinder diagnostic equipment.

Backup Battery Charging

After TCU replacement, vehicle must be driven or kept with ignition on for 60 minutes to fully charge internal backup battery.

Water Ingress Check

Always check for water damage before replacing TCU - fix root cause first to prevent repeat failures.

Antenna Verification

Verify GPS and cellular antenna connections are secure and undamaged during TCU diagnosis.

No Substitutes

TCUs are VIN-locked and must be genuine JLR parts - aftermarket units will not function.

Subscription Activation

InControl services may require reactivation after TCU replacement through JLR customer portal.

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TCU DTC Code Database

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Need Help with TCU Issues?

Lock50 HW04 provides comprehensive solutions for JLR telematics, communication faults, and advanced module diagnostics.

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Related Resources

RFA DTC Database FAQ Locked RFA EVA2 Unlock Guide Supported Models