U0141 on 2008-2015 Mitsubishi Lancer: Causes and Fixes for ETACS Communication Loss

What's Unique About the 2008-2015 Mitsubishi LANCER

The 2008-2015 Lancer platform and its relatives (Outlander, Lancer Evolution) are known for issues with the ETACS-ECU. A safety recall (NHTSA Campaign ID: 14V569000, Mitsubishi SR-15-002) was issued for 2009-2010 Lancer and Outlander models due to internal manufacturing defects in the ETACS-ECU that could cause high electrical resistance. This defect could lead to voltage instability and failure of headlights and wipers. This known weakness means that a U0141 code on this specific vehicle is very likely to be a genuine failure of the ETACS module itself, rather than just a wiring problem.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light or other warning lamps illuminated (e.g., Brake Warning Lamp)
• "Service AWD System" message on the display
• Headlights, taillights, or interior lights not working or acting erratically
• Windshield wipers not working or activating on their own
• Power windows and door locks failing
• Climate control (HVAC) system inoperable
• Key fob (keyless entry) and immobilizer system not working
• Turn signals not functioning
• Vehicle may not start or only crank without starting
• Instrument cluster gauges or lights flickering or going dead

Most Likely Causes

1. Failed ETACS-ECU 🔴 High Probability → Shop Body Control Module A known manufacturing defect prompted a safety recall for 2009-2010 models due to high internal resistance from insufficient adhesion between internal components. Forum discussions and TSBs confirm this is a common failure point across the model years, sometimes due to water damage, internal corrosion, or failure of integrated relays like the one for the fuel pump.
   How to confirm: Use a professional scan tool (like Mitsubishi's M.U.T.-III) to see if it can communicate with the ETACS-ECU. If the module is unresponsive but has proper power and ground at its connectors, it has likely failed. A visual inspection of the module (located in the driver's side footwell, integrated with the fuse box 🎬 Watch: A quick look at inspecting and fixing the ETACS ECU.) for corrosion or water damage is also recommended.
   Typical fix: Replace the ETACS-ECU. The new module must be programmed (VIN writing and custom coding) to the vehicle. It is critical to match the part number of the replacement unit.
   Est. part cost: $150-$450
2. CAN Bus Wiring or Connector Issue 🟡 Medium Probability Wiring can be damaged at pinch points under the dash or near door jambs. The ETACS-ECU's location in the driver's footwell can make it susceptible to corrosion from water entry (e.g., wet shoes, leaky cowl seal).
   How to confirm: Visually inspect the wiring harnesses connected to the ETACS-ECU for damage, chafing, or corrosion. With the battery disconnected, check CAN bus resistance between pins 6 (CAN High) and 14 (CAN Low) at the OBD-II port; it should be ~60 ohms. Check for shorts to power or ground on the CAN lines.
   Typical fix: Repair the damaged section of the wiring harness or clean/replace the corroded connector.
   Est. part cost: $10-$100
3. Poor Power or Ground to ETACS-ECU ⚪ Low Probability → Shop Body Control Module
   How to confirm: Using a multimeter, verify that the ETACS-ECU is receiving proper battery voltage on all its power supply pins and has a solid ground connection at its ground pins. Check related fuses, such as the IOD fuse.
   Typical fix: Repair the faulty power or ground wire, or replace the blown fuse.
   Est. part cost: $1-$20

Diagnosis Steps

1. Connect a professional scan tool (ideally a Mitsubishi M.U.T.-III) capable of reading all vehicle modules. Note all modules that are reporting code U0141.
2. Attempt to communicate directly with the ETACS-ECU (Body Control Module). If communication fails, this strongly points to an issue with the ETACS-ECU itself, its power/ground supply, or the CAN lines connected to it.
3. Check and verify battery voltage and the charging system are functioning correctly. Low voltage can cause communication errors.
4. Inspect the fuses related to the ETACS-ECU and Body Control systems, particularly the IOD (Ignition-Off Draw) fuse.
5. Locate the ETACS-ECU. It is integrated with the interior fuse box in the driver's side footwell, under the dash. You may need to remove a lower dash panel and unbolt the driver's knee airbag (without disconnecting it) for access.
6. Visually inspect the ETACS-ECU connectors and surrounding wiring for signs of corrosion, water intrusion, pushed-out pins, or physical damage.
7. If the visual inspection is clear, use a multimeter to check for battery voltage and a good ground at the appropriate pins on the ETACS-ECU connectors.
8. If power and ground are good, perform a CAN bus integrity test. Disconnect the battery. Measure resistance between CAN High and CAN Low pins at a connector; it should be approximately 60 ohms.
9. If all wiring, power, and grounds are confirmed to be good, and the scan tool cannot communicate with the ETACS-ECU, the module itself is highly likely to be faulty and require replacement.

Parts You'll Likely Need

• ETACS-ECU (Electronic Time and Alarm Control System) (OEM #8637A826) — This is the Body Control Module for the vehicle and is the most common point of failure when a U0141 code is present, often due to internal faults as identified in a safety recall. This specific part number is for the Lancer, Lancer Ralliart, and Lancer Evolution.
  Trusted brands: Mitsubishi Genuine OEM
  OEM price range: $275-$450
  Aftermarket price range: $150-$300 (Used/Remanufactured)
• ETACS-ECU (Lancer Sportback) (OEM #8637A825) — This is the specific ETACS-ECU part number for the Lancer Sportback and Lancer Sportback Ralliart models covered by the safety recall.
  Trusted brands: Mitsubishi Genuine OEM
  OEM price range: $300-$500
  Aftermarket price range: $150-$300 (Used/Remanufactured)

Related Codes That Often Appear With This One

• U0100 (Lost Communication with ECM/PCM)
• U0101 (Lost Communication with TCM)
• U0121 (Lost Communication with ABS Control Module)
• U1417 (Implausible Ignition Key Signal Received)
• Multiple other 'U' codes indicating widespread communication loss

Technical Service Bulletins (TSBs) & Recalls

• TSB-19-54-008: Updates the Chassis Electrical section of the Service Manuals to update diagnostics for ETACS-ECU CAN timeout diagnostics with DTC U0141. This TSB applies to the 2008-2017 Lancer, among other models.
• TSB-19-42B-003: Updates the Body section (KOS/WCM) of the Service Manual to update diagnostics for ETACS-ECU CAN timeout with DTC U0141.
• TSB-19-52B-005: Updates the Supplemental Restraint System (SRS) section of the Service Manuals to update diagnostics for ETACS-ECU CAN timeout diagnostics with DTC U0141.

Platform-Specific Known Issues

• Safety Recall SR-15-002 (NHTSA 14V569000): A safety recall was issued for 2009-2010 Lancer, Lancer Evolution, and Outlander models. Due to a manufacturing error, the ETACS-ECU could have high internal electrical resistance, causing voltage instability and failure of headlights and wipers. The fix was to inspect the production date on the ETACS-ECU and replace it if it was built between October 1, 2008, and August 31, 2010.
• Water Damage and Corrosion: Multiple owner accounts on forums describe finding corrosion and water damage on the ETACS-ECU or its connectors. Its location in the driver's footwell makes it vulnerable to moisture from wet feet or potential water leaks from the cowl or A-pillar area.
• Complex Diagnostic Updates via TSBs: Mitsubishi issued multiple Technical Service Bulletins (TSB-19-42B-003, TSB-19-54-008, TSB-19-52B-005) in 2019 to update the diagnostic procedures for DTC U0141 across many vehicle systems (Body, Chassis Electrical, SRS). This indicates it is a recognized and complex issue requiring specific diagnostic steps.

Mechanic-Grade Diagnostic Values

• CAN Bus Resistance — expected: ~60 Ω (Ohms) between CAN_H and CAN_L pins at the OBD-II port with the battery disconnected.. Failure: A reading of ~120 Ω indicates a missing terminating resistor or an open in one of the CAN lines. A reading near 0 Ω indicates a short circuit between the CAN lines.
• ETACS-ECU Power Supply Voltage — expected: Approximately 12V (system voltage) at connector C-307 (pin 2) to ground and C-309 (pin 1) to ground, with the connector disconnected.. Failure: Significantly lower or no voltage indicates a problem with the power supply circuit, fusible link, or wiring harness.
• ETACS-ECU Ground Circuit Resistance — expected: 2 Ω (Ohms) or less between connector C-315 (pin 17) and body ground, and C-317 (pin 15) and body ground, with the connectors disconnected.. Failure: Higher resistance indicates a poor ground connection, which can cause intermittent communication issues.
• ETACS-ECU ACC Signal Voltage — expected: Approximately 12V (system voltage) at connector C-317 (pin 7) to ground, with the ignition switch in the 'ACC' position (backprobing).. Failure: No voltage indicates a fault in the ignition switch or the wiring between the switch and the ETACS-ECU.

Scan Tool Commands That Help

• Mitsubishi M.U.T.-III: Variant Coding — This function is mandatory after replacing the ETACS-ECU. It configures the new module for the specific options installed in the vehicle (e.g., keyless entry, auto headlights). Failure to perform variant coding will result in incorrect operation of body control functions.
• Mitsubishi M.U.T.-III: Coding Information & Copy — This should be used *before* removing the old ETACS-ECU. It allows the technician to save the existing variant and customization coding to the M.U.T.-III tool, which can then be written to the new module, simplifying the programming process.
• Mitsubishi M.U.T.-III: CAN bus diagnosis — This is the initial step to check the overall health of the network. The tool can identify which modules are not communicating and report bus errors, helping to confirm that the ETACS-ECU is the module that is offline.
• MMCodingWriter: Read/Write ETACS Variant and Custom Coding — This is an aftermarket software tool that provides an alternative to the dealer's M.U.T.-III. It is used by advanced DIYers and independent shops to back up coding from an old ETACS-ECU and write it, along with the vehicle's VIN, to a new or used replacement unit.

Wiring & Ground Locations

• ETACS-ECU — Integrated with the interior fuse box, located in the driver's side footwell under the dashboard.. This is the central module that has lost communication. Physical access is required for inspection, testing of its connectors, and replacement.
• C-307, C-309 — Connectors at the ETACS-ECU.. These connectors contain the main power supply pins for the ETACS-ECU. Voltage checks are performed here to verify the module is receiving power.
• C-315, C-317 — Connectors at the ETACS-ECU.. These connectors contain the main ground pins for the ETACS-ECU. Resistance checks are performed here to verify a solid connection to chassis ground. C-317 also contains the ACC ignition signal wire (pin 7).
• C-301 — A large connector on the ETACS unit. Its position differs on pre-facelift models.. On pre-2011 models, this connector is at the top of the ETACS. On later models, it's at the bottom. When swapping units between these versions, an extension harness is required for this connector.
• Chassis Ground Points — Key grounding points are located on the left and right front chassis rails in the engine bay.. While the ETACS has its own specific ground wires, poor overall chassis grounding can introduce electrical noise and intermittent communication problems across the vehicle.

Real Owner Repair Stories

• YouTube user Dave Michie (Mitsubishi Lancer (year not specified, likely 2008+)) — Hazards would switch on by themselves, rear washer would activate randomly, and the car thought all doors were open constantly. Required turning the car off and on to temporarily resolve.
  ❌ Tried (didn't work) The user directly identified the issue as the ETACS-ECU based on the symptoms controlling multiple unrelated body functions.
  ✅ What actually fixed it Replacing the ETACS-ECU (referred to as EAC ECU in the video). After swapping the module located behind the driver's side interior fuse box, the door-open indicator light began functioning correctly immediately, resolving the issues.

OEM Part Supersession History

• Various older part numbers → 8637A826 — This is the primary replacement part number specified for Lancer, Lancer Ralliart, and Lancer Evolution models in the safety recall campaign SR-15-002.
  Heads up: While this part may be physically compatible with pre-2011 models, the C-301 connector location is different, requiring a harness extension for a proper fit.
• Various older part numbers → 8637A825 — This is the primary replacement part number specified for Lancer Sportback and Lancer Sportback Ralliart models in the safety recall campaign SR-15-002.

Model Year Variations Within This Range

• 2008-2010: Models before the 2011 facelift have the C-301 connector at the top of the ETACS unit. When replacing with a newer style ETACS (like 8637A644 or similar) where the connector is at the bottom, an extension cord for the C-301 harness is required.
• 2014+: Later model year Lancers (approx. 2014+) may have different 'Variant Coding' strings compared to earlier models, containing additional data at the end of the code string that is absent or zeroed-out on older versions.
• 2008-2015: The base 'DE' model Lancer lacks features found in ES, ES Sport, and GTS trims, such as steering wheel buttons and additional power outlets. While the ETACS-ECU is still the central body controller, its programming and connected peripherals will differ significantly from higher-trim models.