U1602

Code

Generic U — Network/User

Invalid Data Received From Control Module

Brand: Generic

Type: U — Network/User

Views: UK: 23 EN: 23 RU: 18

AI status

Completed

ready

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Page language: EN

Causes

Faulty sending or receiving control module (internal processor/software)
Corroded, loose or damaged connector or spliced wiring on the network
Short, open or high-resistance on data/ground/termination circuits
Incorrect or incompatible software/calibration in one or more modules
Missing or incorrect bus termination or harness modification
Intermittent battery/charging voltage or weak ground causing data corruption

Symptoms

MIL or warning messages for affected systems
Loss of function of one or more networked systems (e.g., ABS, transmission, HVAC, instrument cluster)
Intermittent or permanent communication errors on scan tool
Erratic instrument cluster values or frozen gauges
Other modules reporting dependent faults or fallback modes

What to check

Read all stored and pending U- and P- codes from all modules; note freeze frame and timestamp data
Identify which module reported the invalid data and all related modules on the same bus
Visually inspect wiring, connectors, and grounds for the affected module(s) and any junctions or gateways
Check battery voltage and charging system for stability (while cranking and at idle)
Verify vehicle history: recent module replacement, software update, aftermarket installs, or collision repairs
Use an appropriate scan tool to request/monitor the suspect module’s messages and see if it responds to diagnostic requests

Signal parameters

Bus type (CAN, CAN-FD, LIN, FlexRay) and associated baud rate (e.g., 500 kbps, 250 kbps)
Message ID(s) expected from the sender and timestamps/cycle time (ms)
Data length (DLC) and expected data payload structure for the message
Frequency and regularity of frames (cycle time and jitter)
Count of CRC/FEC errors, faulty/error frames, and bus error counters
CAN_H and CAN_L voltages in recessive and dominant states and differential voltage behavior

Diagnostic algorithm

Retrieve all modules’ codes and note which module logged U1602 and any associated codes. Identify the network (CAN/LIN) and message IDs involved.
Inspect connectors, pins, and wiring harnesses for corrosion, bent pins, or damage at the reporting module and common junctions. Repair as necessary.
Verify battery and ground integrity. Ensure battery voltage stable (while cranking and idling) and grounds are clean/tight.
With correct vehicle wiring diagrams, check continuity and resistance of the data wires and shield/ground back to the gateway/module. Look for shorts to power/ground.
Using a capable scan tool or OEM diagnostic tester, monitor raw bus traffic. Confirm whether the sending module is transmitting valid frames (correct ID, DLC, expected payload pattern) or sending malformed frames.
Use an oscilloscope or CAN/LIN analyzer to inspect CAN_H/CAN_L physical layer for noise, missing recessive/dominant transitions, reflections or excessive error frames.
If bus wiring and physical layer are good, verify module software/calibration levels for compatibility. Reflash or update software if mismatched per manufacturer procedure.
If a specific module is identified as the source after steps above, verify power/ground/inputs to that module. Replace the module only after confirming failure and ruling out wiring and software causes.
Clear codes and retest the system. Drive-cycle as required and re-scan to confirm the fault is resolved.
If intermittent, trace and reproduce conditions (temperature, vibration, accessory connection) and consider harness repair or shielding for EMI sources.