U0515

Code

Generic U — Network/User

Invalid Data Received From Remote Function Actuation Module

Brand: Generic

Type: U — Network/User

Views: UK: 42 EN: 55 RU: 39

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty Remote Function Actuation (RFA) module
Corroded/loose connector or pin at the RFA module
Damaged wiring harness (shorts, opens, chafing) on power, ground or network wires
Low or unstable battery/vehicle supply voltage
CAN/LIN bus errors (noise, missing termination, wiring fault)
Software/firmware mismatch or required reprogramming of the RFA module

Symptoms

No response or intermittent response to remote lock/unlock/remote start functions
Inoperative or erratic remote start or keyless entry functions
Related modules display communication warnings or function limitations
Illumination of the master warning light or info messages on the instrument cluster
Stored network communication DTCs in other modules

What to check

Scan vehicle and record all stored and pending U and B codes; capture freeze frame and data stream
Check battery state-of-charge and system voltage (battery & charging)
Visually inspect RFA module connector and wiring for corrosion, bent pins, or damage
Check RFA module power and ground circuits for correct voltage and low resistance ground
Check for related network codes (U0100, U0121, etc.) that identify bus-wide issues
Using a scan tool, verify the RFA module is present on the network and attempt to communicate with it

Signal parameters

Vehicle battery supply voltage to RFA module: approx. 12–14.5 V during normal operation
Module ground resistance: close to 0 Ω (low resistance)
Network message frequency for RFA messages: frequency and CAN IDs expected by OEM (capture with scanner/oscilloscope)
CAN bus differential waveform: clean recessive and dominant states, no excessive noise or distortion
Bus error counters and UDS/ISO-TP responses from the RFA module when queried

Diagnostic algorithm

Retrieve all DTCs from all modules and note freeze frame data and times. Check for multiple U‑codes to determine if problem is isolated or bus‑wide.
Verify battery voltage and charging system health. Low/unstable voltage can corrupt messages — ensure battery ≥12 V with engine off and charging system within spec with engine running.
Visually inspect the RFA module connector and wiring harness. Repair any damage, push connectors fully home and check for bent pins or corrosion.
With a scan tool, attempt to communicate with the RFA module and view live data/messages. Note if the module responds or times out.
Check power and ground at the RFA module: verify constant and switched power circuits are present and ground has low resistance to chassis. Repair any power/ground faults.
Inspect network (CAN/LIN) wiring for physical damage. Measure termination resistor(s) and check for wiring continuity and shorts between High/Low and to chassis.
Capture CAN/LIN traffic with an oscilloscope or a capable scan tool while operating remote functions. Look for malformed frames, unexpected IDs, CRC errors, or excessive bus noise.
Disconnect known aftermarket devices (alarms, repeaters, remote starters). Clear codes and attempt to reproduce. If codes do not return, investigate aftermarket device causes.
If wiring and bus are good but invalid messages persist, check software/calibration levels and perform OEM‑recommended reprogramming of the RFA module or gateway if available.
If after all electrical and software checks the module still transmits invalid data, replace the RFA module per OEM procedure and confirm repair by clearing codes and retesting functions.

Likely causes

Poor ground or fused power feed to the RFA module
Connector corrosion at the RFA or gateway module
Network short to chassis or between CAN high/low wires
Faulty RFA module firmware or calibration requiring reflash
Aftermarket remote or amplifier injecting invalid messages on the bus

Fault status

⚠️ Status

Invalid data or malformed message received from the Remote Function Actuation module on the vehicle network. Communication/data integrity fault detected; functions controlled by the RFA may be degraded.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 2.5 hours