U0214

Code

Generic U — Network/User

Lost Communication With Remote Function Actuation Module

Brand: Generic

Type: U — Network/User

Views: UK: 22 EN: 67 RU: 31

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in the data bus wiring between RFAM and network
RFAM power or ground fault (blown fuse, bad connector, corroded pin)
Failed RFAM (internal electronics or microcontroller)
Bus termination or CAN bus physical layer fault
Intermittent connector/corrosion or pin damage
Faulty gateway/module that routes messages between networks

Symptoms

Remote keyless entry, remote start, alarm or liftgate may not operate
Malfunction indicator or network warning on instrument cluster
Other modules show related communication DTCs
No response from RFAM when attempting diagnostics with scan tool
Intermittent operation of remote functions

What to check

Check for other network DTCs that indicate broader bus failures
Verify scan tool can communicate with vehicle and other modules
Inspect fuses and relays supplying power to the RFAM
Visually inspect RFAM connector and harness for corrosion, damage or loose pins
Check battery voltage and key-on power to RFAM
Perform wiggle test on harness with key on while monitoring bus

Signal parameters

Network type: typically CAN (Controller Area Network) — verify vehicle-specific bus
Nominal idle voltages: CANH ≈ 2.5–3.5 V, CANL ≈ 1.5–2.5 V (both ≈2.5 V at recessive)
Dominant state voltages: CANH rises and CANL falls (expected differential ~2 V)
Termination: combined resistance across CANH–CANL ≈ 60 ohms (two 120 ohm terminators)
Expected communication: RFAM heartbeat or status messages at periodic intervals (varies by vehicle)
Message IDs: manufacturer-specific; use dealer or service data to identify RFAM TX/RX IDs

Diagnostic algorithm

Connect a capable scan tool and confirm U0214 and any related DTCs. Record freeze frame and events.
Verify the scan tool itself can communicate with the vehicle and attempt to communicate directly with RFAM. Note if module appears offline.
Check battery voltage (should be within specification) and relevant fuses/relays for RFAM power. Replace any blown fuses and retest.
Visually inspect RFAM connector and wiring for damage, corrosion, bent pins, or water intrusion. Repair as necessary.
With ignition on, measure key-on power and ground at the RFAM connector. Repair any open power/ground circuits.
Probe the CAN bus at the RFAM connector: measure CANH and CANL voltages, then measure differential. Compare to expected values.
Check bus termination resistance across CANH–CANL at two locations; replace or repair missing/incorrect terminations.
Perform a wiggle and backprobe test on the wiring while monitoring bus traffic/messages with the scan tool or oscilloscope to locate intermittent faults.
If physical layer is good and RFAM still does not communicate, check gateway/module that routes RFAM messages — verify it is powered and communicating.
If wiring and gateway check OK, follow vehicle-specific procedures to reprogram or replace the RFAM. After replacement/programming, clear codes and verify communication and function.
If problem is intermittent or only after key cycles, monitor vehicle during real-world operation or use data logger to capture failure conditions.

Likely causes

Blown fuse or lost key-on power to RFAM
Damaged or disconnected RFAM connector or wiring harness
Short to battery or ground on CANH/CANL near RFAM
Corroded pins in RFAM connector causing intermittent comms
Failed RFAM unit
Missing or incorrect module programming after replacement

Fault status

⚠️ Status

U0214 — Lost Communication With Remote Function Actuation Module. The vehicle network is not receiving expected messages from the RFAM; the module appears offline or its messages are absent on the data bus.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours