U1601

Code

Generic U — Network/User

Invalid Data Received From Control Module

Brand: Generic

Type: U — Network/User

Views: UK: 24 EN: 32 RU: 21

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty or intermittent wiring/connectors on vehicle data bus (CAN, LIN, FlexRay, etc.)
Poor module power or ground causing corrupted transmissions
Faulty or misbehaving control module sending corrupted messages
Incorrect or mismatched software/calibration in one or more modules
Bus termination or physical layer fault (missing/shorted termination resistor, high resistance)
High electrical noise or low battery/voltage fluctuations causing corrupted frames

Symptoms

MIL (Check Engine) illuminated or multiple network-related DTCs present
Loss of function for systems that rely on the affected module (e.g., ABS, HVAC, instrument cluster, transmission faults)
Intermittent or permanent communication errors reported by scan tool
Unexpected or frozen instrument cluster messages/values
Symptoms may be intermittent and correlated with vibration, temperature, or connector movement

What to check

Read all stored and pending DTCs and freeze-frame/diagnostic data with a capable scan tool
Note which modules report communication errors and the time/frequency of occurrence
Check battery voltage and charging system for adequate voltage during tests
Visually inspect connectors and wiring harnesses along the bus for damage, corrosion, or loose pins
Verify module power and ground circuits (voltage at power pin, low resistance to chassis ground)
Check bus physical layer: measure CAN high/low voltages with ignition ON and with bus active (expect ~2.5V idle, differential ~0V idle; see vehicle documentation)

Signal parameters

CAN bus: CAN_H ~2.5 V idle, CAN_L ~2.5 V idle, differential ~0 V idle; active differential ±1 to 3 V depending on load
Message frequency (Hz) for expected ID — compare to OEM specs
Message ID (CAN ID) and expected byte length for the affected signal
Checksum or CRC field if used by the OEM message
Message sequence/counter values (should increment predictably)
Bus error counters (if available in diagnostic data)

Diagnostic algorithm

Connect a professional scan tool that can read module communication data, freeze-frame, and network statistics.
Record which modules report U1601 or related network DTCs and capture any freeze frame or sequence/counter data.
Visually inspect all connectors and wiring associated with modules on the affected bus; repair any damaged pins, corrosion, or loose connectors.
With ignition ON, measure battery voltage and verify stable supply to all modules on the bus. Repair charging/battery issues if found.
Verify module grounds: backprobe ground pins and confirm low-resistance path to chassis; clean/repair grounds as needed.
Measure CAN_H and CAN_L idle voltages and differential voltage. If voltages are out of range, isolate wiring and inspect for shorts, high resistance, or missing termination.
If bus physical layer is good, check for a single misbehaving module by disconnecting modules one at a time (per OEM safe procedures) and observing whether the error clears. Do not disconnect modules that will cause unsafe vehicle conditions.
Check for and apply any available software/calama updates or programming differences if a recently replaced module or reflash occurred.
After repairs, clear codes, perform a drive cycle or reproduction steps to confirm the issue is resolved and re-scan for recurrence.
If the fault persists and module isolation identifies a single module, consult OEM diagnostics for advanced module bench testing or replacement guidance.

Likely causes

Loose or corroded connector or pin at affected module(s)
Intermittent module power/ground resulting in corrupted messages
CAN bus wiring chafing or short causing dropped/garbled frames
One control module with incorrect software/calibration after recent service or reflash

Fault status

⚠️ Status

Invalid data received from control module — communication message format or integrity failure (checksum/sequence/counter or unexpected values) detected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-4 hours