Code
U1705
Generic
U — Network/User
Invalid Data Received from Network Control Module
AI status
Completed
Completed
100%
Causes
- Faulty or misconfigured Network Control Module (NCM)
- Corrupted or garbled CAN/LIN messages on the vehicle data bus
- Damaged wiring, poor connector contacts, or corrosion on communication lines
- Incorrect or incomplete module programming/software mismatch
- Intermittent power, ground, or supply voltage issues to a module
- Missing or incorrect bus termination (open or shorted termination resistor)
Symptoms
- Malfunction indicator lamp (MIL) or communication warning illuminated
- Loss or intermittent operation of systems controlled via network (depending on which messages are invalid)
- Multiple modules reporting communication-related codes
- Inconsistent or missing data on scan tool (missing PIDs/telemetry)
- Slow or unresponsive infotainment, body, or convenience features
What to check
- Scan all modules and record U/C/P codes, freeze frame and occurrence counts
- Check battery voltage and charging system; test while cranking and at key-on
- Visual inspection of connectors and wiring for damage, corrosion or water
- Inspect CAN bus termination resistors across CAN_H and CAN_L (approx. 60 Ω total)
- Use a scan tool or oscilloscope to monitor CAN bus traffic and voltages
- Disconnect aftermarket accessories that may be on the bus
Signal parameters
- CAN High and CAN Low DC voltages (key ON, idle, active frames)
- Differential voltage during dominant and recessive states (CAN_H - CAN_L)
- Bus error counters and bus-off flags from modules (if available)
- Message IDs, frequency (messages/sec), payload length and CRC if supported
- Presence/absence of expected messages from the Network Control Module
- Module supply voltage and ground integrity
Diagnostic algorithm
- Retrieve and record all stored codes (global and module-specific), note freeze frame and occurrence frequency; do not clear yet.
- Verify battery state (12.6 V nominal resting) and charging system; correct low/unstable voltage conditions and retest.
- Visually inspect NCM and related harness connectors for damage, corrosion, or water intrusion; repair any issues found.
- Check CAN bus termination between CAN_H and CAN_L (~60 Ω). If out of range, isolate and locate open/short/failed termination.
- With a capable scan tool or oscilloscope, capture CAN traffic while reproducing the fault. Look for malformed frames, unexpected IDs, excessive error frames, or bus-off conditions.
- Isolate the fault by disconnecting suspected modules (one at a time) from the bus while observing changes in errors/traffic. Use known-good module if available.
- Perform wiggle tests on connectors/harnesses while monitoring bus and codes to find intermittent breaks or shorts.
- Verify module software/calibration levels against OEM specifications; reprogram or update software if mismatched or corrupted.
- After repairs or updates, clear codes and perform road/functional test to confirm the code does not return and that affected systems operate normally.
- If the fault persists and wiring and bus integrity are confirmed, replace the failing module following OEM procedures and program as required.
Likely causes
- Failed NCM or other module transmitting malformed packets
- Open, short to voltage/ground, or high resistance in CAN High/Low pair
- Low battery or unstable supply to a transmitting module
- Module recently replaced without correct VIN calibration or software
- Damaged connector pins or water intrusion at a module connector
- Bus termination resistor faulty or missing (incorrect 60 ohm total)
Fault status
Status
Invalid data was received from the Network Control Module — communication messages failed validation or contained unexpected values/format.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
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