U0158 Code: Lost Communication With Telematics Control Module

U0158 is a generic OBD-II network communication diagnostic trouble code indicating that one or more vehicle control modules have lost communication with the Telematics Control Module. The exact function and name of this module can vary between manufacturers and may be associated with cellular communication, GPS, emergency assistance, remote vehicle services, or other connected-vehicle functions.

The module designation, location, network architecture, wiring configuration, and diagnostic procedure vary by vehicle. Always use manufacturer-specific service information for the final diagnosis.

U0158 Code Details

Code: U0158
Meaning: Lost Communication With Telematics Control Module
Type: Generic OBD-II Network Communication Code
Main System: Telematics / Vehicle Communication Network

Symptoms of U0158

Telematics or connected-car functions may stop working.
Remote vehicle services may become unavailable.
GPS or vehicle-location functions may be interrupted.
Emergency assistance or communication features may not operate.
Telematics-related warning messages may appear.
Multiple communication-related DTCs may be stored.
The scan tool may be unable to communicate with the affected module.
Intermittent network communication problems may occur.

Common Causes of U0158

Low battery voltage.
Blown fuse supplying the telematics module.
Missing battery or ignition power supply.
Poor or damaged module ground.
Open CAN High or CAN Low circuit.
Shorted or damaged communication wiring.
Loose or corroded electrical connector.
Damaged terminals or poor terminal tension.
Water intrusion.
Another control module interfering with the communication network.
Internal telematics module failure.
Incorrect module programming or configuration.

How Serious Is U0158?

U0158 is generally a moderate communication fault, but its importance depends on the functions supported by the telematics system. A communication failure can disable connected services, remote functions, GPS-related features, or emergency communication functions.

If emergency assistance or other safety-related telematics functions are unavailable, the fault should be diagnosed promptly.

Can You Drive With U0158?

In many vehicles, U0158 will not directly prevent the engine from starting or affect basic driving. However, connected services and some emergency or communication functions may be unavailable while the fault is active.

How to Diagnose U0158

1. Scan All Control Modules

Perform a complete system scan and record U0158 together with any other communication, voltage, body, or network codes. Determine whether the telematics module is the only module that has stopped communicating.

2. Check Battery and Charging Voltage

Verify battery condition and charging-system voltage. Low system voltage during starting can cause electronic modules to reset or temporarily disappear from the network.

3. Check Telematics Module Fuses

Use the vehicle-specific fuse diagram to identify all fuses supplying the telematics module. If a fuse is blown, determine the cause before replacing it.

4. Test Power and Ground

Verify the required battery and ignition feeds and test the module ground according to manufacturer specifications. A missing power or ground supply can make a healthy module appear to be offline.

5. Inspect Connectors and Wiring

Inspect the telematics module connector for corrosion, loose terminals, bent pins, water contamination, damaged locks, or poor terminal tension. Check the wiring harness for cuts, chafing, and previous repairs.

6. Check CAN Communication

Inspect CAN High and CAN Low circuits for opens, shorts, damaged insulation, corrosion, or poor connections. Follow the vehicle wiring diagram because the module may communicate through a particular CAN network or gateway.

7. Check for Another Module Affecting the Network

If several modules report lost communication, investigate common network circuits and other modules before replacing the telematics module.

8. Test the Telematics Module

If power, ground, connectors, and network circuits are verified, follow the manufacturer's diagnostic procedure to determine whether the module has an internal failure or requires programming or configuration.

U0158 Oscilloscope Signal Patterns

An oscilloscope can be useful when U0158 is associated with an intermittent or distorted CAN communication problem. It can help identify abnormal network activity when conventional voltage and continuity checks do not reveal the fault.

Normal / Active

Y X

Normal: Consistent CAN communication activity with clean signal transitions.

Abnormal / Distorted

Y X

Abnormal: Noise, distortion, irregular transitions, or intermittent network activity.

Inactive / No Communication

Y X

Inactive: Expected network communication activity is absent at the tested network point.

Important: These are simplified diagnostic illustrations, not manufacturer-specific waveform specifications. Actual CAN High and CAN Low voltage levels, timing, and network behavior must be compared with the specifications for the exact vehicle.

U0158 Diagnostic Signal Flow

Scan Tool
↓
Vehicle CAN Communication Network
↓
Telematics Control Module
↓
GPS / Cellular / Connected Services
↓
Other Vehicle Control Modules

U0158 OBD Live Data

Available parameters depend on the vehicle and scan tool. Where supported, useful information may include telematics communication status, system voltage, network status, GPS status, cellular connection status, emergency-service status, and related module information.

Common Repairs for U0158

Repair missing telematics module power supply.
Repair poor or damaged module ground.
Replace a failed fuse after identifying the cause.
Repair damaged CAN High or CAN Low wiring.
Repair loose, corroded, or damaged connectors.
Repair damaged terminals or wiring harnesses.
Correct water intrusion.
Repair another module disrupting the communication network.
Repair or replace the telematics module when internal failure is confirmed.
Program, configure, or initialize the replacement module when required.

U0158 Repair Cost

Electrical/network diagnosis: approximately $100–$200+.
Fuse or wiring repair: approximately $75–$300+.
Connector/terminal repair: approximately $80–$250+.
Telematics module repair: approximately $150–$600+.
Module replacement and programming: approximately $400–$1,500+ depending on vehicle.

These are general estimates only. Actual costs depend on vehicle model, module type, parts availability, labor rates, and programming requirements.

Common Repair Mistakes

Replacing the telematics module before checking power and ground.
Ignoring low battery voltage.
Failing to inspect the module connector.
Replacing the module without testing CAN communication circuits.
Assuming every stored U-code means a failed module.
Ignoring another module that may be affecting the CAN network.
Failing to perform required programming or configuration after replacement.

Related OBD-II Codes

U0100 – Lost Communication With ECM/PCM.
U0121 – Lost Communication With ABS Control Module.
U0140 – Lost Communication With Body Control Module.
U0150 – Lost Communication With Gateway Module "A".
U0155 – Lost Communication With Instrument Panel Cluster.
U0156 – Lost Communication With Information Center Module.
U0157 – Lost Communication With Telematics Control Module.

FAQ About U0158

Can a weak battery cause U0158?

Yes. Low system voltage can cause the telematics module or other control modules to reset or temporarily stop communicating.

Can a CAN wiring problem cause U0158?

Yes. An open, shorted, damaged, or poorly connected CAN circuit can interrupt communication with the telematics module.

Does U0158 mean the telematics module is bad?

No. The module power supply, ground, fuses, connectors, and CAN circuits should be tested before condemning the module.

Can U0158 affect connected-car functions?

Yes. Depending on the vehicle, loss of communication may affect GPS, remote services, cellular connectivity, emergency assistance, or other telematics functions.

Can an oscilloscope help diagnose U0158?

Yes. An oscilloscope can help identify abnormal CAN activity, electrical noise, distortion, or intermittent communication when a network fault is suspected.

Does a replacement telematics module need programming?

Many vehicles require programming, configuration, coding, or initialization after telematics module replacement. The exact procedure depends on the manufacturer and vehicle.

Final Takeaway

U0158 is a generic OBD-II network communication code indicating lost communication with the Telematics Control Module.

A systematic diagnosis should begin with battery voltage, fuses, module power and ground, connectors, and CAN communication circuits. The telematics module should only be replaced after its electrical supply and network communication have been properly verified.