U0073 on 2006-2012 Toyota RAV4: Control Module Communication Bus 'A' Off Explained

What's Unique About the 2006-2012 Toyota RAV4

For the third-generation Toyota RAV4 (2006-2012), the U0073 code is often linked directly to the Skid Control ECU, which contains the ABS module. This specific component is a known weak point and can fail internally, disrupting the entire CAN network. An internal failure can cause the module to either stop communicating entirely or, more destructively, broadcast corrupt data that floods the bus and prevents other modules from communicating (a "bus off" state). While wiring or other module failures are possible, the Skid Control ECU is a very common point of failure for this particular communication code on this RAV4 generation.

Symptoms You May Notice

• Multiple warning lights on the dashboard, including Check Engine, ABS, VSC, and TRAC OFF. Often described as a 'Christmas tree' effect.
• Vehicle may not start or may stall unexpectedly.
• Loss of power steering assist (if equipped with electric power steering).
• Transmission may shift erratically or get stuck in one gear.
• Gauges on the instrument cluster may behave erratically or stop working.
• A professional scan tool may be unable to communicate with multiple control modules.
• Cruise control becomes inoperative.

Most Likely Causes

1. Weak or Failing Battery 🔴 High Probability Low system voltage is a very common trigger for network communication codes on many modern vehicles, including this RAV4. Modules require a stable voltage (typically above 10V) to communicate properly. A sudden voltage drop during startup can cause modules to initialize incorrectly and throw communication faults.
   How to confirm: Test the battery voltage with a multimeter. A healthy, fully charged battery should read approximately 12.6 volts with the engine off. With the engine running, the alternator should be charging it at around 13.7 to 14.7 volts. A load test is the most definitive way to confirm battery health. One owner reported fixing U0073 and associated codes after discovering their system voltage was only 9V and replacing the battery.
   Typical fix: Recharge or replace the battery. Ensure battery terminals are clean and tight.
   Est. part cost: $100-$250
2. Faulty Skid Control ECU (ABS Module) 🔴 High Probability This specific module is a known failure point on the 2006-2012 RAV4. An internal fault can cause it to stop communicating or, worse, broadcast corrupt data that brings down the entire CAN network. Toyota documentation specifically lists conditions under which the Skid Control ECU will set a U0073 code. Due to the high cost of new OEM units, many owners opt to have their original module repaired by a specialized service or purchase a used unit.
   How to confirm: After confirming good power and ground to the module, a technician will use a scan tool to see if the Skid Control ECU is offline. They may also measure CAN bus resistance while disconnecting the module to see if the network returns to a normal state (approx. 120 ohms with one terminator disconnected). If the bus functions normally with the Skid Control ECU unplugged, the module is condemned. Check for 10-14V at pin 46 (IG1) and continuity to ground at pins 1 (GND2) and 32 (GND1) on the Skid Control ECU connector A19.
   Typical fix: Replace the Skid Control ECU (Brake Actuator Assembly) and perform any necessary calibration or programming. Alternatively, send the original module to a service like XeMODeX for repair and re-installation, which often comes with a warranty and avoids the need for programming.
   Est. part cost: $800-$2000+ for a new OEM part, $200-$500 for a repair service, $150-$400 for a used part.
3. Damaged Wiring or Corroded Connectors 🟡 Medium Probability The CAN bus harness runs throughout the vehicle. Wires can become chafed, pinched, or damaged from previous repairs or rodent activity. Connectors, especially those in exposed areas or under carpets where moisture can collect, can corrode and cause a loss of connection.
   How to confirm: Visually inspect the wiring harness for obvious damage. A technician will measure resistance between CAN High and CAN Low at the OBD-II port (pins 6 and 14). A reading of ~60 ohms is normal. 120 ohms indicates a break in the circuit or a missing terminating resistor (often inside a module). Near 0 ohms indicates a short circuit.
   Typical fix: Repair the damaged section of wiring or clean/replace the corroded connector.
   Est. part cost: $5-$100 (for repair supplies)

Rare But Worth Checking

• Faulty Engine Control Module (ECM) or other module: While less common than the Skid Control ECU, any module on the CAN bus can theoretically fail and bring down the network. Diagnosis involves systematically disconnecting modules to isolate the faulty one.
• Poor Ground Connection: A corroded or loose main ground for the ECM or another major module can introduce electrical noise and communication errors. Always check major ground points.
• Aftermarket Electronics: Improperly installed remote starters, alarms, or stereos that are tapped into the CAN bus wiring can interfere with communication and trigger a U0073 code.

Diagnosis Steps

1. Check the battery. Ensure it is fully charged and the terminals are clean and tight. A weak battery is a common cause of network codes.
2. Perform a full system scan with a professional-grade scan tool to see which modules are reporting 'no communication'. Note if U0129 is present, as this strongly points to the Skid Control ECU.
3. Visually inspect the main wiring harnesses, especially around the ECM, Skid Control ECU, and under the driver's side dash, for any signs of damage, corrosion, or rodent activity.
4. Measure the resistance of the CAN bus at the OBD-II connector (pins 6 and 14). A healthy network should read approximately 60 ohms. A reading of 120 ohms suggests an open circuit or a failed terminating resistor in a module. A reading near zero ohms indicates a short between the two CAN wires.
5. If the resistance is incorrect, begin disconnecting modules from the CAN bus one at a time, starting with the most likely suspect (the Skid Control ECU). After unplugging each module, re-measure the resistance. If the reading returns to normal after unplugging a specific module, that module is likely the cause of the fault.
6. If wiring is suspected, check for continuity and shorts to power/ground on the CAN High and CAN Low wires.
7. Verify that the suspect module has proper power and ground connections before condemning it. For the Skid Control ECU, check for 10-14V at pin 46 and less than 1 Ω to ground at pins 1 and 32 of connector A19.

Parts You'll Likely Need

• Skid Control ECU / Brake Actuator Assembly (OEM #Varies by year and 2WD/4WD. Examples: 44510-42150, 44050-42190, 44540-42110. The assembly is often labeled with a base part code of 44510.) — This is a very common failure point on the 2006-2012 RAV4 that directly causes the U0073 code by disrupting the CAN bus.
  Trusted brands: Toyota (OEM), Advics, Cardone (remanufactured), XeMODeX (Repair Service)
  OEM price range: $1500-$2500
  Aftermarket price range: $600-$1200
• Vehicle Battery — Low system voltage from a weak or failing battery is a primary cause of network communication faults.
  Trusted brands: Interstate, DieHard, Duralast, Toyota TrueStart
  OEM price range: $150-$250
  Aftermarket price range: $100-$200

Related Codes That Often Appear With This One

• U0100 — Lost Communication with ECM/PCM. This code often appears with U0073 because if the entire bus is down, no module can communicate with the engine computer.
• U0129 — Lost Communication With Brake System Control Module. This is a strong indicator that the Skid Control ECU (which houses the brake control module) is the source of the problem.
• U0123, U0124, U0126 — Lost communication with Yaw Rate, Lateral Acceleration, or Steering Angle sensors. These codes point toward a failure in the Vehicle Stability Control system, which is managed by the Skid Control ECU.

Platform-Specific Known Issues

• The Skid Control ECU (ABS Module) on the XA30 RAV4 is a well-documented failure point leading to U0073. The failure is internal to the module's electronics. Due to the high replacement cost from Toyota, repair services or warrantied used units are a popular alternative.

Mechanic-Grade Diagnostic Values

• CAN Bus Resistance at OBD-II Port (Pins 6 & 14) — expected: 54 to 69 Ω (approximately 60 Ω). Failure: 120 Ω indicates an open circuit or one terminator offline. ~0 Ω indicates a short between CAN High and CAN Low.
• Skid Control ECU (Connector A19) Power Supply — expected: 10 to 14 V at Pin 46 (IG1) with ignition ON. Failure: No voltage indicates a power supply issue to the module.
• Skid Control ECU (Connector A19) Ground Connection — expected: Below 1 Ω resistance to body ground at Pin 1 (GND2) and Pin 32 (GND1). Failure: High resistance indicates a poor ground connection, a common cause of module communication errors.

Hidden / Shadow Codes Worth Checking

• U0073/94: This is the Toyota-specific designation for the generic U0073 code, often seen in Techstream software. The '/94' is an additional identifier. (see via Toyota Techstream or other advanced, professional-grade scan tools.)

Scan Tool Commands That Help

• Toyota Techstream: Zero Point Calibration — This procedure is mandatory after replacing the Skid Control ECU, Yaw Rate Sensor, or Steering Angle Sensor. It calibrates the sensors to the vehicle's straight-and-level state. Failure to perform this will result in ABS/VSC warning lights and stored codes like C1290 or C1336.
• Toyota Techstream: Reset Memory — This function should be performed before the Zero Point Calibration when a new or used Skid Control ECU is installed. It clears any stored calibration data from the previous module.
• Toyota Techstream: CAN Bus Check — This utility can be used to actively monitor the communication status of all modules on the CAN bus, helping to identify which module is not responding or is causing the network to go down.

Wiring & Ground Locations

• Skid Control ECU Connector (A19) — Located on the ABS actuator assembly in the engine compartment, typically on the passenger side against the firewall.. This is the main connector for the most common cause of the fault. Testing for power (Pin 46), ground (Pins 1, 32), and CAN signals (Pins 11, 25) happens here.
• CAN Junction Connectors (No. 1, No. 3) — These connectors branch the CAN bus to various ECUs. Their locations vary but are often found behind the instrument panel or kick panels.. Corrosion or loose pins in these junction connectors can disrupt the entire network, causing a U0073 code.
• ECM/ECU Ground Points — On the 2GR-FE V6 engine, key harness grounds are located on the valve covers, often near the VVT-i oil line attachment and another on the side of the cylinder head under the throttle body.. A poor ECU ground can cause a wide range of electrical issues, including communication codes. These points should be checked for corrosion and tightness.

Real Owner Repair Stories

• RAV4World Forum User (2007 Toyota RAV4 V6 Sport) — ABS, VSC, 4WD, and brake lights all came on. Codes U0073, U0123, U0124, U0126 were present.
  ❌ Tried (didn't work) Replacing the battery., Checking all fuses., Inspecting wiring for visible damage.
  ✅ What actually fixed it The owner sent the original Skid Control ECU (ABS module) to a repair service (ModuleMaster). After receiving the repaired module and reinstalling it, all codes were cleared and the issue was resolved.
• NHTSA ODI #10851309 — An owner reported the ABS and brake lights came on while the speedometer, odometer, and A/C stopped working. The dealer found code U0073 and replaced the ABS actuator assembly, including the pump and ECU.
• NHTSA ODI #10704941 — A report describes how an actuator assembly failure resulted in various warning lights and "RPMs started bouncing" along with communication code U0073.
• NHTSA ODI #10639478 — One owner noted that while code U0073 was present, the dealership was initially unable to pinpoint the exact problem, highlighting the complexity of CAN bus diagnostics.

Documented NHTSA Reports

• NHTSA ODI #11697829 — A report on a similar Toyota platform describes the dashboard displaying ABS, brake, engine, and master warning lights with code U0073 present, even though rear brake lights functioned normally.
• NHTSA ODI #11681883 — In some Toyota models, a U0073 code has been recorded alongside water pump failures and "top where it's safe" messages, where coolant loss was the primary mechanical issue.

Model Year Variations Within This Range

• 2009-2012: The 2009 model year received a facelift which included some electronic updates. While the fundamental cause (Skid Control ECU failure) remains the same, part numbers for the ABS module may differ from the 2006-2008 models. Always verify the part number on the original unit before ordering a replacement.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Excessive Oil Consumption (2.4L 2AZ-FE Engine) 🔴 High — Very common on 2006-2008 models, often starting between 75,000 and 150,000 miles. Caused by faulty piston ring design. (Ref: Toyota issued a Warranty Enhancement Program (ZE7) to address this, but it has since expired.)
• Steering Intermediate Shaft Clunk 🟠 Medium — Common on 2006-2010 models, typically a clunking or knocking noise from the steering column when turning at low speeds. Occurs after 70,000+ miles. (Ref: Toyota released Technical Service Bulletins (e.g., T-SB-0028-22 for a similar issue on other models) with procedures to replace the shaft.)
• Water Pump Failure 🟠 Medium — A common failure item on both 4-cylinder and V6 models of this generation, often occurring after 80,000 miles. Symptoms include coolant leaks and whining noises.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used Skid Control ECU (ABS module) is a very common and sensible repair for this vehicle, given the high cost of a new OEM part. Many salvage yards offer tested units with a warranty.

Donor-vehicle mileage cap: roughly under 150000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Verify the part number on the used module EXACTLY matches your original module.
• Buy from a reputable salvage yard that offers at least a 90-day warranty.
• Inspect the electrical connector pins for any signs of corrosion or damage.
• Ask if the donor vehicle's history is known (e.g., was it a flood vehicle? Avoid if so).

Aftermarket brands forum-validated for this vehicle:

• Cardone (Remanufactured)
• XeMODeX (Repair Service)
• ModuleMaster (Repair Service)

Brands owners have reported issues with on this vehicle:

• Unbranded, no-name modules from online marketplaces without a warranty or return policy.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• U0129 — Lost Communication with Brake System Control Module; if present alongside U0073, it strongly points to a failure of the Skid Control ECU.
• C1241 — Low Battery Positive Voltage or Abnormally High Battery Voltage; often appears when a weak battery triggers network communication faults like U0073.
• U0100 — Lost Communication with ECM/PCM; another common network code that may appear when the CAN bus is disrupted by wiring damage or voltage drops.
• U0121 — Lost Communication with Anti-Lock Brake System (ABS) Control Module; frequently accompanies U0073 when the Skid Control ECU fails internally.

Frequently Asked Questions