U0113 — Data bus: emissions critical control information – no communication #

Note: The description for code U0113 may vary depending on the vehicle manufacturer (OEM). Always consult OEM documentation for your specific model.

• U0113: Lost Communication With Emissions Critical Control Module (Ford)
• U0113: Data Bus: Emissions Critical Control Information – No Communication (Volkswagen Group/Audi/Skoda/Seat)
• U0113: Lost Communication With Emissions Control Module (General Motors)
• U0113: CAN Communication Error – Emissions Critical Control Module (Hyundai/Kia)

Summary of code U0113 #

The U0113 diagnostic trouble code (DTC) indicates that the vehicle’s main control unit, usually the Engine Control Module (ECM) or Powertrain Control Module (PCM), has lost communication with a vital emissions-related control module. In simple terms, the car’s computer network—known as the Controller Area Network (CAN) bus—is not receiving data from a module essential for monitoring or controlling emissions. This code often points to an underlying issue with wiring, connectors, power supply, or sometimes a faulty module itself. On modern vehicles, this can affect the car’s ability to meet emission standards and may trigger a check engine light or limp mode. The specific component involved can vary by OEM, but the root issue is always a communication breakdown between ECUs.

Frequent symptoms for code U0113 #

When code U0113 is stored, you might notice a range of symptoms—some obvious, others more subtle. The most common sign is the Check Engine Light (CEL) or a specific warning related to emissions or the vehicle’s communication system. In some cases, there may be drivability issues, such as reduced power or delayed response from the engine. Sometimes, the only symptom is a failed emissions test or the inability to complete certain readiness monitors during inspection.

• Check Engine Light (CEL) illuminated
• Warning messages on the dashboard (e.g., “Emissions System Problem”)
• Reduced engine performance or limp mode
• Failed state emission test or incomplete readiness monitors
• Possible rough idle or hesitation when accelerating
• Other communication-related DTCs present

Probable causes for code U0113 (from most to least common) #

The root causes of U0113 almost always relate to a breakdown in communication within the vehicle’s electronic network. This can stem from something as simple as a loose connector, or as complex as a failed module. Here are the most common culprits, ranked by likelihood:

1. Loose, corroded, or damaged wiring/connectors at the emissions control module or along the related CAN bus circuits
2. Open circuit (broken wire) or short to power/ground on the CAN High or CAN Low communication lines
3. Faulty emissions critical control module (such as a NOx sensor module, Diesel Particulate Filter (DPF) module, or SCR module, depending on vehicle type)
4. Loss of power or ground at the affected module (blown fuse, bad relay, poor ground)
5. Faulty Engine Control Module (ECM) or Powertrain Control Module (PCM) (rare)
6. Aftermarket devices interfering with CAN communication (e.g., remote starters, alarm systems)

Step-by-step diagnosis for code U0113 #

Diagnosing U0113 requires patience and attention to detail, as communication faults can be elusive. The key is to systematically check wiring, power supply, and the integrity of the network—like a detective following a trail of clues through a maze of wires and modules. Here’s a proven diagnostic approach:

• Step 1: Verify the code and note any related DTCs using a professional scan tool capable of reading all modules.
• Step 2: Check for technical service bulletins (TSBs) related to U0113 or communication issues for your specific vehicle/OEM.
• Step 3: Inspect the affected module’s fuse(s) and relay(s) for proper function and continuity.
• Step 4: Visually inspect wiring and connectors at the emissions critical control module. Look for loose pins, corrosion, or physical damage.
• Step 5: Test for proper power (battery voltage) and ground at the module using a multimeter.
• Step 6: Check CAN High and CAN Low circuits for continuity, opens, or shorts using wiring diagrams and a multimeter or oscilloscope.
• Step 7: Disconnect any aftermarket devices from the CAN lines and retest.
• Step 8: If all wiring checks out, try swapping the suspected module with a known-good one (if possible) or perform an OEM-level module self-test.
• Step 9: Clear codes and perform a road test to confirm repair.

Possible repairs for code U0113 #

Repairing U0113 is about restoring reliable communication on your vehicle’s digital “nervous system.” The fix will depend on what the diagnostic process uncovers, but here are the most common repairs linked to each cause:

• Repair or replace damaged wiring or connectors at the emissions control module or along the CAN bus
• Clean or reseat corroded connectors and apply dielectric grease where appropriate
• Replace blown fuses or faulty relays supplying the emissions control module
• Replace the emissions critical control module itself (after confirming power, ground, and network integrity)
• Repair open or shorted CAN communication lines
• Remove or rewire aftermarket devices that interfere with CAN communication
• In rare cases, replace the ECM/PCM if it is proven to be the source of the communication issue

Is it safe to drive with code U0113? #

Driving with U0113 is not recommended for extended periods. While the vehicle may still operate, emissions control systems may be compromised, leading to increased pollution and possible engine performance issues. In some cases, the car may enter limp mode, reducing power to protect itself. Additionally, your vehicle will likely fail an emissions inspection. If the check engine light is flashing or the vehicle feels unsafe, stop driving and seek professional help immediately.

Vehicles most commonly affected by code U0113 #

U0113 is most often found on modern vehicles equipped with advanced emission control modules connected to the CAN bus. It is particularly common on diesel vehicles due to the number of emissions-related modules required. Here are some models and brands where U0113 is frequently reported:

• Ford F-Series, Transit, Ranger (especially diesel variants)
• Volkswagen Golf, Passat, Jetta, Tiguan, Touareg (TDI models)
• Audi A3, A4, Q5, Q7 (diesel and gasoline)
• Chevrolet Silverado, Colorado, Cruze (diesel)
• Ram 1500/2500/3500 EcoDiesel
• Hyundai and Kia diesel models
• BMW 3 Series, 5 Series, X5 (diesel variants)

Common mistakes & best practices for code U0113 #

When tackling U0113, it’s easy to overlook the basics or jump to conclusions. Many costly module replacements can be avoided by checking the simple things first. Here’s what to watch for and how to approach this code efficiently:

• Don’t replace the suspected module before verifying power, ground, and network integrity
• Always check for related codes—U-codes often occur in clusters and can help narrow down the fault
• Remember to disconnect aftermarket devices during diagnosis
• Use proper OEM wiring diagrams and connector pinouts
• After repair, always clear codes and perform a drive cycle to ensure the issue is resolved

U0113 FAQ express #

Here are some quick answers to the most common questions about U0113:

• Q: Can a weak battery or poor charging system cause U0113?
  A: Yes, low system voltage can disrupt communication between modules. Always check battery health before deeper diagnostics.
• Q: Will U0113 clear itself after repair?
  A: Sometimes, but it’s best to clear the code with a scan tool and confirm the fix with a road test.
• Q: Does U0113 mean my car will fail emissions testing?
  A: Most likely, since the emissions system can’t be properly monitored with this fault present.