U0406 — Invalid Data Received From Fuel Injector Control Module

U0406 — Invalid Data Received From Fuel Injector Control Module. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: faulty fuel rail pressure sensor or wiring, clogged or leaking fuel injectors, vacuum or intake leaks skewing the mixture.

vehicle network

Is it safe to drive?

Drive with caution Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.

How to diagnose with an OBD scanner

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm U0406 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the fuel delivery and mixture control for damage, corrosion, chafing or poor contact.
  4. Subsystem check Measure fuel pressure at the rail and compare with factory specification at idle and under load.
  5. Subsystem check Check short-term and long-term fuel trims in live data to see which way the mixture is off.
  6. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0406 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for U0406 (parts and labor, USD, independent shop rates): Clean or replace injectors: $200–$800; Replace the fuel filter: $80–$200; Replace the fuel pump: $400–$900; Replace the pressure regulator or sensor: $150–$450. Overall, fixing U0406 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What is the most common cause of U0406?

The most common causes are: faulty fuel rail pressure sensor or wiring, clogged or leaking fuel injectors, vacuum or intake leaks skewing the mixture.

What are the symptoms of U0406?

Drivers most often notice: loss of power under load, Check Engine Light on, hard starting or long cranking, rough idle and hesitation.

How much does it cost to fix U0406?

Clean or replace injectors — $200–$800; Replace the fuel filter — $80–$200; Replace the fuel pump — $400–$900; Replace the pressure regulator or sensor — $150–$450. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What does OBD2 code U0406 mean?

U0406 — Invalid Data Received From Fuel Injector Control Module. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: faulty fuel rail pressure sensor or wiring, clogged or leaking fuel injectors, vacuum or intake leaks skewing the mixture.

Is it safe to drive with U0406?

Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.

What does U0406 mean?

U0406 (Invalid Data Received From Fuel Injector Control Module) is stored when self-diagnostics detect abnormal readings or behaviour of the fuel delivery and mixture control. It belongs to the vehicle network category.

The module monitors this system continuously while driving. When readings fall outside the expected range for a defined number of drive cycles, it stores U0406 and switches on the warning light. Freeze frame data saved with the code shows the exact conditions — rpm, load, temperature, speed — at the moment the fault was detected, which is the best starting point for diagnosis.

What causes U0406?

  • clogged or leaking fuel injectors
  • contaminated or incorrect fuel
  • weak fuel pump or clogged fuel filter
  • faulty fuel rail pressure sensor or wiring

Common symptoms of U0406

  • loss of power under load
  • Check Engine Light on
  • hard starting or long cranking
  • rough idle and hesitation
  • fuel smell in severe cases

How to diagnose U0406

  1. Connect an OBD2 scanner, confirm U0406 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Visually inspect the wiring harness and connectors related to the fuel delivery and mixture control for damage, corrosion, chafing or poor contact.
  4. Measure fuel pressure at the rail and compare with factory specification at idle and under load.
  5. Check short-term and long-term fuel trims in live data to see which way the mixture is off.
  6. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0406 does not return.

How to fix U0406

Start with the cheapest and most common causes before replacing expensive parts:

  • Clean or replace injectors — $200–$800
  • Replace the fuel filter — $80–$200
  • Replace the fuel pump — $400–$900
  • Replace the pressure regulator or sensor — $150–$450

How much does it cost to fix U0406?

Repair cost depends on which component actually failed. Typical scenarios for U0406 (parts and labor, USD, independent shop rates):

  • Clean or replace injectors: $200–$800
  • Replace the fuel filter: $80–$200
  • Replace the fuel pump: $400–$900
  • Replace the pressure regulator or sensor: $150–$450

Overall, fixing U0406 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with U0406?

Drive with caution. Mixture and fuel-pressure faults can cause stalling, hesitation in traffic and — when severe — catalyst damage. Avoid long trips until diagnosed.

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