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Home / DTC / U3115 — Invalid data received on CAN bus

U3115 — Invalid data received on CAN bus

Detailed page for trouble code U3115.

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U3115

Generic U — Network/User

Invalid data received on CAN bus

Brand: Generic
Type: U — Network/User
Views: UK: 0 EN: 2 RU: 1
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Page language: EN

Causes

  • Physical wiring damage (short, open, corroded connector)
  • Missing or incorrect CAN termination resistor(s)
  • Low or unstable battery/charging system voltage during communication
  • Faulty or intermittent ECU/module transmitting corrupt frames
  • Software mismatch or firmware bug in one or more modules
  • Incorrect bus speed/configuration or mismatched transceiver

Symptoms

  • Communication errors or intermittent loss of data from one or more modules
  • Related controllers show additional U- or B- codes
  • Malfunction indicator lamps or degraded system performance for systems on that bus
  • Intermittent operation of features (e.g., instrument cluster, ABS, HVAC) that rely on affected messages
  • Network message count or error frame count increased when monitored

What to check

  • Retrieve freeze frame and full scan-tool data; note which module reported U3115 and associated P/B/C/U codes
  • Visually inspect CAN connectors and wiring for damage, corrosion, loose pins, or improper repairs
  • Measure battery voltage and charging system under key ON and while reproducing the fault
  • Measure resistance across CAN_H and CAN_L with ignition off to verify termination (typical ~60 ohm across pair for two 120 Ω terminators)
  • Use a scan tool/oscilloscope to monitor CAN traffic, message IDs, DLC, error frames, and bus voltages
  • Check for software/firmware updates or known TSBs related to CAN communication for vehicle and modules

Signal parameters

  • CAN message ID(s) for the affected signals (inspect live traffic for unexpected IDs)
  • Data Length Code (DLC) — verify message length matches specification
  • Message transmission frequency / period (Hz or ms)
  • CAN_H to CAN_L differential voltage waveform (look for proper dominant/recessive levels, expected differential ~2.0V when dominant)
  • Bus bit rate (e.g., 125 kbps, 250 kbps, 500 kbps) and bit timing consistency
  • Error frame count and transmit/receive error counters on module

Diagnostic algorithm

  1. Read all modules and record freeze frame, occurrence count, and any other U-codes. Note which module set U3115.
  2. Check battery and charging voltage. Repair any low/unstable voltage conditions before further testing.
  3. Perform a visual inspection of CAN wiring, connectors, and grounds for the affected bus segment. Repair obvious damage.
  4. Measure termination resistance across CAN_H and CAN_L with ignition off (expected ~60 Ω total for two 120 Ω terminators).
  5. Use a scan tool or scope to monitor CAN traffic while recreating the fault. Look for malformed frames, incorrect DLC, unexpected IDs, high error-frame rates, or bus voltage anomalies.
  6. If a specific transmitter is suspected, temporarily isolate or disconnect that module (follow manufacturer safety/disconnect procedures) and check if U3115 clears or communication stabilizes.
  7. Swap or reprogram suspect module(s) with known-good firmware if available, or update software per manufacturer bulletins.
  8. Repair or replace damaged wiring, connectors, or transceivers as indicated by testing. Replace termination resistors or add missing terminators if required.
  9. After repairs, clear codes, perform a thorough functional test and road test to confirm the fault does not recur. Re-scan for pending codes and monitor live bus traffic.

Likely causes

  • Damaged connector or wiring on CAN_H/CAN_L in the affected segment
  • Intermittent module failing to transmit valid frames (faulty transceiver or software)
  • Missing/incorrect termination resistor causing reflections and corrupted frames
  • Battery/charging system voltage irregularity affecting transceiver performance

Fault status

⚠️ Status
U3115 — Invalid data received on CAN bus. Set when an ECU detects corrupted, malformed, out-of-spec, or incorrectly timed CAN frames from another node. May be intermittent or continuous depending on the underlying issue.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0100 U0073 U0121 U0415 U1000
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