U0168 medium Severity

U0168: Lost Communication With Vehicle Security Control Module

May not immediately impact engine performance, but can affect immobilizer, security, and starting functions

Overview

U0168 indicates a communication failure on the CAN bus between the vehicle security control module and other control modules, often due to wiring, power issues or module faults

Common Symptoms

  • Security or immobilizer warning light on dashboard
  • Remote key fob functions unresponsive
  • Engine fails to start or stalls
  • Alarm system won’t arm or disarm

Most Common Causes

Open, shorted, or corroded CAN bus wiring or connectors high

Loss of communication often originates from harness issues affecting the data bus signals

Loss of power or ground to the vehicle security control module high

Blown fuses or poor grounds are common triggers

Faulty Vehicle Security Control Module (VSCM) or related module medium

Module internal failure or firmware issues can prevent proper communications

Low battery voltage or unstable supply medium

Electrical supply irregularities can disrupt CAN communication

Diagnostic Steps

  1. Retrieve all stored codes with a scan tool capable of network diagnostics
    Expected: U0168 present, note additional codes
    Interpretation: Isolates U0168 as active or stored and checks related network faults
  2. Check fuses, power and ground connections for the vehicle security control module
    Expected: Proper voltage and secure grounds
    Interpretation: Validates that module power supply is intact
  3. Visually inspect CAN bus wiring and connectors for damage or corrosion
    Expected: No broken wires, corrosion or pin damage
    Interpretation: Identifies physical wiring faults causing communication loss
  4. Attempt direct communication with the security module using scan tool
    Expected: Module responds with data or codes
    Interpretation: If no response, localizes fault to module or wiring
  5. Perform continuity checks on CAN high/low circuits and voltage checks with DVOM
    Expected: Expected voltage levels and continuity
    Interpretation: Confirms integrity of the CAN signaling paths

Repair Solutions

Repair or replace damaged wiring/connectors on CAN bus medium
Estimated Cost: $50 - $250

Depends on extent of wiring damage

Restore proper power and ground to security control module easy
Estimated Cost: $10 - $80

Fuse replacement or cleaning grounds

Replace Vehicle Security Control Module (VIN‑matched & programmed) hard
Estimated Cost: $600 - $1150

Includes module cost and programming

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Interpreting U0168 as a primary engine fault due to generic network code

Frequently Asked Questions

Technical definition of U0168 OBD-II Code

Lost Communication With Vehicle Security Control Module is the standard definition for U0168. This diagnostic code is triggered when the ECU detects a problem in the Sensors.

Should I stop driving if I have U0168?

The U0168 code is considered medium severity. May not immediately impact engine performance, but can affect immobilizer, security, and starting functions

What happens when the U0168 code is active?

The most typical signs are: Security or immobilizer warning light on dashboard, Remote key fob functions unresponsive, Engine fails to start or stalls.

What causes the U0168 code?

It can be caused by several factors, most notably: Open, shorted, or corroded CAN bus wiring or connectors, Loss of power or ground to the vehicle security control module, Faulty Vehicle Security Control Module (VSCM) or related module.

Estimated repair costs for different causes of U0168

It depends on what needs to be fixed. Restore proper power and ground to security control module repairs are cheaper (~$80), while Replace Vehicle Security Control Module (VIN‑matched & programmed) repairs are on the higher end (~$1150).

Is U0168 a generic or manufacturer-specific code?

Yes, U0168 is a generic code that applies to all OBD-II compliant vehicles, including Ford, Toyota, Honda, Chevrolet, Nissan, Dodge, BMW, and more.

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