U0167 — Data Bus: Immobilizer Control Module – No Communication / Engine Control Module – Internal Fault #

Note: The description for DTC U0167 may vary depending on the vehicle manufacturer (OEM).

• “Lost Communication With Immobilizer Control Module” (General, Ford, GM, Toyota)
• “No Communication With Immobilizer Module” (Honda, Nissan, Mazda)
• “Engine Control Module – Internal Fault” (Volkswagen, Audi)
• “CAN Bus: Immobilizer Module No Communication” (Mercedes-Benz, BMW)

Summary of DTC U0167 #

The U0167 diagnostic trouble code signals a loss of communication between the vehicle’s main computer—known as the Engine Control Module (ECM) or Powertrain Control Module (PCM)—and the immobilizer control module. The immobilizer module is an anti-theft device that verifies the key or transponder before allowing the engine to start. When these two modules cannot exchange data over the vehicle’s communication network, called the Controller Area Network (CAN) bus, the ECM logs the U0167 code. This condition often leads to starting issues or immobilization, but symptoms can vary depending on the OEM’s system design.

Frequent Symptoms for Code U0167 #

A vehicle with a U0167 code typically displays clear warning signs that something is amiss with the security or starting system. While some symptoms are hard to miss, others may appear sporadically. Here’s what you should watch for:

• Engine cranks but won’t start
• Security or immobilizer warning light illuminated on dashboard
• Intermittent no-start condition
• Key fob not recognized or remote start fails
• Check Engine Light (CEL) or Service Engine Soon (SES) light on
• Possible “No Communication” message during OBD scan

Likely Causes for Code U0167 #

The most common triggers for code U0167 relate to wiring, network faults, or module failures. Understanding the order of likelihood can save time and frustration during diagnosis:

1. Faulty or disconnected wiring between the immobilizer module and ECM/PCM
2. Defective immobilizer control module (water ingress, internal circuit failure)
3. ECM/PCM malfunction (software or hardware-related)
4. CAN bus communication issue (broken wire, poor ground, corroded connector)
5. Blown fuse or failed relay supplying power to control modules
6. Aftermarket alarm or remote start system interfering with OEM wiring
7. Low battery voltage or inconsistent power supply

Step-by-Step Diagnostic for U0167 #

Resolving U0167 starts with a logical and methodical approach. Rushing can lead to missed details—think of it like following a treasure map, where each clue brings you closer to the solution:

• Confirm the U0167 code and note any companion codes using a professional scan tool.
• Visually inspect all wiring and connectors between the immobilizer and ECM/PCM for damage, corrosion, or loose pins.
• Check fuses and relays related to the immobilizer and ECM circuits.
• Test battery voltage and ensure stable power supply to all modules.
• With a scan tool, check for communication with the immobilizer module—if absent, attempt communication at the module directly if possible.
• If wiring and power checks are good, test CAN bus integrity using a multimeter or oscilloscope.
• Swap with a known good immobilizer module if available (OEM procedure may require reprogramming).
• If all else fails, suspect a faulty ECM/PCM or consider software updates as per OEM technical service bulletins (TSB).

Possible Repairs for U0167 #

The right fix for U0167 depends on the underlying cause. Here’s how each issue is typically resolved:

• Wiring repair or replacement: Fix damaged wires, clean corroded connectors, and ensure tight terminal fitment.
• Replace immobilizer control module: Install a new OEM module and perform necessary key programming or module pairing.
• ECM/PCM replacement or reprogramming: Install a new or remanufactured unit and reflash with the latest software as required.
• CAN bus repair: Replace or repair broken/bad segments of the network wiring.
• Replace blown fuse/relay: Address electrical supply issues to affected modules.
• Remove or correct aftermarket device installation: Restore original wiring if non-factory alarm or remote start systems have been installed incorrectly.
• Charge or replace weak battery: Ensure stable battery voltage for all control modules.

Is It Safe to Drive with Code U0167? #

No. Most vehicles with an active U0167 code will not start, as the immobilizer system prevents unauthorized operation. Even if the engine starts intermittently, you risk sudden immobilization, leaving you stranded or unable to restart the vehicle. It’s crucial to address this code promptly to restore reliable operation and maintain vehicle security.

Most Commonly Affected Vehicles by U0167 #

While U0167 can appear in almost any modern vehicle equipped with an immobilizer, some makes and models report it more frequently—often related to specific wiring vulnerabilities or module locations.

• Ford Focus, Fiesta, Escape (2012–present)
• Honda Civic, Accord (2010–present)
• Volkswagen Jetta, Golf, Passat (2008–present)
• Toyota Corolla, Camry, RAV4 (2012–present)
• Nissan Altima, Sentra (2013–present)
• Mazda 3, 6, CX-5 (2014–present)
• BMW 3 Series, 5 Series (F-chassis, 2012–present)

Common Mistakes & Best Practices for U0167 #

Diagnosing U0167 can be tricky—missteps often lead to wasted time or unnecessary expense. Avoid these pitfalls and stick to proven techniques:

• Overlooking the basics: Always check fuses, relays, and battery voltage before replacing expensive modules.
• Ignoring wiring issues: Damaged or corroded connectors are more common than failed modules.
• Skipping OEM service bulletins: Some U0167 issues are known to manufacturers and have specific repair procedures.
• Swapping modules without programming: Many immobilizer modules require programming or pairing to the vehicle and keys.
• Neglecting aftermarket modifications: Incorrectly installed alarms or remote starts can break communication lines.

U0167 Code Express FAQ #

Still have questions about U0167? Here are quick answers to common concerns:

• Q: Can a dead battery trigger U0167?
  A: Yes, low or unstable battery voltage can disrupt module communication and cause U0167, especially after jump-starting or battery replacement.
• Q: Do I need special tools to fix U0167?
  A: A professional-grade scan tool is highly recommended for communication checks and module programming. Basic tools (multimeter, test light) suffice for wiring and fuse checks.