U3016 — Control Module Input Power B Circuit Open

OBD2 code U3016 flags a problem with the vehicle network (CAN bus) communication (U3016 - control module input power b circuit open). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, a faulty module pulling the bus down.

vehicle

Is it safe to drive?

Drive with caution Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

How to diagnose with an OBD scanner

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm U3016 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 vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
  4. Subsystem check Do a continuity test end-to-end on the U3016 - control module input power b circuit and wiggle the harness while measuring — intermittent opens show up as fluctuating readings.
  5. Subsystem check Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
  6. Subsystem check Scan all modules: the one that does not respond is either the culprit or downstream of the break.
  7. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U3016 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for U3016 (parts and labor, USD, independent shop rates): Remove interfering aftermarket device: $0–$150; Repair CAN wiring or connectors: $100–$400; Replace the faulty control module: $300–$1,500. Overall, fixing U3016 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What are the symptoms of U3016?

Drivers most often notice: intermittent loss of functions (gauges, windows, steering assist), no-start or intermittent starting in some cases, random, hard-to-reproduce electrical glitches, modules intermittently not communicating with the scanner.

What is the most common cause of U3016?

The most common causes are: damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, a faulty module pulling the bus down.

How much does it cost to fix U3016?

Remove interfering aftermarket device — $0–$150; Repair CAN wiring or connectors — $100–$400; Replace the faulty control module — $300–$1,500. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Is it safe to drive with U3016?

Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

How do I diagnose U3016 myself?

Start with a scan: confirm U3016, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the U3016 - control module input power b, and verify the suspect component against live data before buying parts.

U3016 — U3016 - Control Module Input Power B Circuit Open

What does U3016 mean?

Behind U3016 is a specific failure in the vehicle network (CAN bus) communication: U3016 - control module input power b circuit open. The onboard computer stores it in the vehicle group after verifying the fault over repeated checks.

“Circuit open” means the electrical path of the U3016 - control module input power b circuit is broken: no current flows where the module expects it. This is usually a broken wire, a disconnected or corroded connector, a blown fuse, or an internally open component.

This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with U3016 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.

Common symptoms of U3016

  • intermittent loss of functions (gauges, windows, steering assist)
  • no-start or intermittent starting in some cases
  • random, hard-to-reproduce electrical glitches
  • modules intermittently not communicating with the scanner
  • multiple warning lights on at once

What causes U3016?

  • broken wire in the U3016 - control module input power b harness
  • connector unplugged, backed-out pin or heavy corrosion
  • internally open U3016 - control module input power b
  • blown fuse feeding the circuit
  • corroded connectors, especially in wet areas
  • damaged CAN bus wiring or short to power/ground
  • aftermarket equipment interfering with the bus
  • a faulty module pulling the bus down
  • water ingress in harness junctions

How to diagnose U3016

  1. Connect an OBD2 scanner, confirm U3016 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 vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
  4. Do a continuity test end-to-end on the U3016 - control module input power b circuit and wiggle the harness while measuring — intermittent opens show up as fluctuating readings.
  5. Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
  6. Scan all modules: the one that does not respond is either the culprit or downstream of the break.
  7. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U3016 does not return.

How to fix U3016

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

  • Remove interfering aftermarket device — $0–$150
  • Repair CAN wiring or connectors — $100–$400
  • Replace the faulty control module — $300–$1,500

How much does it cost to fix U3016?

Repair cost depends on which component actually failed. Typical scenarios for U3016 (parts and labor, USD, independent shop rates):

  • Remove interfering aftermarket device: $0–$150
  • Repair CAN wiring or connectors: $100–$400
  • Replace the faulty control module: $300–$1,500

Overall, fixing U3016 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with U3016?

Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

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