U0113

Universal

Lost Communication With Emissions Critical Control Information

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The vehicle has detected that emissions-critical control information is not being received over its communication network. This code identifies a communication problem, not proof that a particular module or part has failed. Depending on which systems rely on the missing information, the warning light may come on or engine operation and emissions control may be affected; some vehicles may show no noticeable symptoms.

Report an error with this code

⚠️ Before You Begin (Safety First)

If the engine stalls, runs very poorly, or the vehicle becomes unsafe to control, stop driving when it is safe to do so and arrange an inspection. If the vehicle drives normally, have the code diagnosed promptly. Avoid probing wiring or connectors while the ignition is on, and leave any high-voltage or safety-system work to a qualified technician.

Common Symptoms

  • The check-engine or another warning light may be on because the vehicle detected missing emissions-critical information.
  • There may be no noticeable symptoms if the missing information does not immediately affect how the vehicle operates.
  • Engine performance or emissions control may be affected if a control system depends on the unavailable information.
  • Other communication-related codes or missing scan-tool data may appear if the communication problem affects additional systems.

Common Causes

  • A loose, damaged, corroded, or poorly connected wire or connector may interrupt communication.
  • A fault in the vehicle communication network may prevent the relevant information from reaching its destination.
  • A power-supply or ground problem at a participating control module may stop it from communicating.
  • Low vehicle system voltage may disrupt communication or produce related codes.
  • A control module, or its software or configuration, may be at fault; the code alone does not establish this.

Diagnostic Steps

  1. Record the code and any other codes before clearing them; related codes can help show whether the issue affects one system or several.
  2. Check whether the battery is discharged or the vehicle has had recent starting or charging problems, since low voltage can interfere with module communication.
  3. With the vehicle safely parked and the ignition off, visually inspect accessible wiring and connectors for looseness, damage, or corrosion. Do not disconnect unfamiliar connectors or probe network wiring.
  4. Check only accessible, clearly identified fuses using the owner's manual; replace a blown fuse only with the specified type and rating, and seek diagnosis if it blows again.
  5. If the code returns or symptoms are present, arrange a scan of all modules and vehicle-specific electrical testing rather than replacing a part based on this code alone.

When to Call a Professional

Scan all accessible modules and record their codes and communication status before clearing anything. Use model-specific service information to identify the affected communication path, then check relevant module power, grounds, connectors, wiring, and network signals with suitable equipment. Consider low system voltage and applicable software or configuration issues before condemning a module.

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Commonly Asked Questions

Does U0113 prove that an emissions-control module has failed?

No. It reports lost communication with emissions-critical control information. Wiring, connectors, power, ground, network faults, low voltage, or a module or software issue may be involved.

Can I drive with U0113?

If the vehicle runs and handles normally, arrange diagnosis promptly and watch for changes. Stop driving when safe if it stalls, runs very poorly, or becomes unsafe to control.

Why might there be no symptoms?

The vehicle may still operate normally if the missing information is not currently needed for an obvious function. A warning light or stored code can occur without a clear change in how the vehicle feels.

What helps distinguish a network problem from a failed module?

A technician can compare codes and communication status across modules, then check the relevant module's power and ground, inspect the communication path, and test network signals using vehicle-specific information.

Browse Available Code Guides

Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.