Code
U0400
Generic
U — Network/User
Invalid Data Received
Views:
UK: 23
EN: 72
RU: 36
AI status
Completed
Completed
100%
Causes
- Faulty or failing control module sending invalid messages
- Intermittent or failed network wiring/connectors (CAN, LIN, etc.)
- Poor battery/charging/ground causing electrical noise or voltage drops
- Bus termination or impedance problems (missing/failed termination resistors)
- Software mismatch or corrupted module programming/calibration
- Conflicting aftermarket device or module reprogramming
Symptoms
- Illuminated MIL (Check Engine) or other warning lights
- Incorrect or frozen instrument cluster readings
- Loss of some driveability or vehicle functions (cruise, stability, etc.)
- Intermittent faults that may clear and return
- Multiple communication-related trouble codes present
- Slow or no response from affected systems controlled by the module
What to check
- Read freeze frame and related U/P/B codes; note which modules report errors
- Check vehicle battery voltage and charging system under load
- Inspect CAN/LIN wiring harnesses and connectors for damage, corrosion, or loose pins
- Use a scanner to monitor live bus traffic and watch for malformed messages or missing IDs
- Measure CAN_H and CAN_L voltages with key on engine off and while communicating
- Check for proper bus termination resistance (≈60 ohms total for two 120 Ω resistors)
Signal parameters
- CAN recessive voltage: CAN_H ≈ 2.5 V and CAN_L ≈ 2.5 V (idle, key on)
- CAN dominant voltages: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V) during traffic
- Total bus termination: ≈ 60 ohms (two 120 Ω resistors in parallel)
- Common data rates: 125 kb/s, 250 kb/s, 500 kb/s, 1 Mbps — message timing should match manufacturer spec
- Message parameters to monitor: expected message ID(s), signal frequency/cycle time, data length, checksum/CRC validity
Diagnostic algorithm
- Retrieve and record all DTCs and freeze frame data from all modules. Note time/conditions and any related U or P codes.
- Verify battery state of charge and charging system (low voltage can corrupt communications). Repair charging/battery faults first.
- Visually inspect connectors and wiring on affected modules and along the main data bus. Repair any damaged or corroded connectors.
- With a professional scan tool, observe bus traffic: verify presence, frequency and content of expected messages from the suspected sender(s).
- Measure CAN_H and CAN_L voltages with key on, engine off; then while communicating. Confirm differential amplitude is within expected range.
- Check bus termination resistance between CAN_H and CAN_L at key points (should be ≈60 Ω across the bus). Replace missing/failed terminators.
Likely causes
- Damaged wiring or loose connector on the vehicle data bus
- One module is malfunctioning and sending corrupted messages
- Battery/alternator voltage out of specification causing communication errors
- Failed or missing CAN bus termination resistor(s)
- Software update required or incorrect module flash
Fault status
Status
Invalid data received on the vehicle network. Check network wiring, module communication, power/ground and module software before replacing modules.
Repair difficulty: Medium
Diagnostic time: 1.0-3.5 hours
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop Manual199,00 UAH
Audi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop Manual199,00 UAH
AUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop Manual199,00 UAH
Audi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop Manual199,00 UAH
Audi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop Manual199,00 UAH
Audi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop Manual199,00 UAH
Audi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop Manual199,00 UAH
Audi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop Manual199,00 UAH
LAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
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Code
U0400
HYUNDAI
U — Network/User
Invalid Data Received
Views:
UK: 13
EN: 32
RU: 24
AI status
Completed
Completed
100%
Causes
- Faulty or failing control module sending invalid messages
- Intermittent or failed network wiring/connectors (CAN, LIN, etc.)
- Poor battery/charging/ground causing electrical noise or voltage drops
- Bus termination or impedance problems (missing/failed termination resistors)
- Software mismatch or corrupted module programming/calibration
- Conflicting aftermarket device or module reprogramming
Symptoms
- Illuminated MIL (Check Engine) or other warning lights
- Incorrect or frozen instrument cluster readings
- Loss of some driveability or vehicle functions (cruise, stability, etc.)
- Intermittent faults that may clear and return
- Multiple communication-related trouble codes present
- Slow or no response from affected systems controlled by the module
What to check
- Read freeze frame and related U/P/B codes; note which modules report errors
- Check vehicle battery voltage and charging system under load
- Inspect CAN/LIN wiring harnesses and connectors for damage, corrosion, or loose pins
- Use a scanner to monitor live bus traffic and watch for malformed messages or missing IDs
- Measure CAN_H and CAN_L voltages with key on engine off and while communicating
- Check for proper bus termination resistance (≈60 ohms total for two 120 Ω resistors)
Signal parameters
- CAN recessive voltage: CAN_H ≈ 2.5 V and CAN_L ≈ 2.5 V (idle, key on)
- CAN dominant voltages: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V) during traffic
- Total bus termination: ≈ 60 ohms (two 120 Ω resistors in parallel)
- Common data rates: 125 kb/s, 250 kb/s, 500 kb/s, 1 Mbps — message timing should match manufacturer spec
- Message parameters to monitor: expected message ID(s), signal frequency/cycle time, data length, checksum/CRC validity
Diagnostic algorithm
- Retrieve and record all DTCs and freeze frame data from all modules. Note time/conditions and any related U or P codes.
- Verify battery state of charge and charging system (low voltage can corrupt communications). Repair charging/battery faults first.
- Visually inspect connectors and wiring on affected modules and along the main data bus. Repair any damaged or corroded connectors.
- With a professional scan tool, observe bus traffic: verify presence, frequency and content of expected messages from the suspected sender(s).
- Measure CAN_H and CAN_L voltages with key on, engine off; then while communicating. Confirm differential amplitude is within expected range.
- Check bus termination resistance between CAN_H and CAN_L at key points (should be ≈60 Ω across the bus). Replace missing/failed terminators.
Likely causes
- Damaged wiring or loose connector on the vehicle data bus
- One module is malfunctioning and sending corrupted messages
- Battery/alternator voltage out of specification causing communication errors
- Failed or missing CAN bus termination resistor(s)
- Software update required or incorrect module flash
Fault status
Status
Invalid data received on the vehicle network. Check network wiring, module communication, power/ground and module software before replacing modules.
Repair difficulty: Medium
Diagnostic time: 1.0-3.5 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
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0
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Code
U0400
LAND ROVER
U — Network/User
Invalid data received (code of failure in event diagnosis)
Views:
UK: 14
EN: 27
RU: 15
AI status
Completed
Completed
100%
Causes
- Faulty or failing control module sending invalid messages
- Intermittent or failed network wiring/connectors (CAN, LIN, etc.)
- Poor battery/charging/ground causing electrical noise or voltage drops
- Bus termination or impedance problems (missing/failed termination resistors)
- Software mismatch or corrupted module programming/calibration
- Conflicting aftermarket device or module reprogramming
Symptoms
- Illuminated MIL (Check Engine) or other warning lights
- Incorrect or frozen instrument cluster readings
- Loss of some driveability or vehicle functions (cruise, stability, etc.)
- Intermittent faults that may clear and return
- Multiple communication-related trouble codes present
- Slow or no response from affected systems controlled by the module
What to check
- Read freeze frame and related U/P/B codes; note which modules report errors
- Check vehicle battery voltage and charging system under load
- Inspect CAN/LIN wiring harnesses and connectors for damage, corrosion, or loose pins
- Use a scanner to monitor live bus traffic and watch for malformed messages or missing IDs
- Measure CAN_H and CAN_L voltages with key on engine off and while communicating
- Check for proper bus termination resistance (≈60 ohms total for two 120 Ω resistors)
Signal parameters
- CAN recessive voltage: CAN_H ≈ 2.5 V and CAN_L ≈ 2.5 V (idle, key on)
- CAN dominant voltages: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V) during traffic
- Total bus termination: ≈ 60 ohms (two 120 Ω resistors in parallel)
- Common data rates: 125 kb/s, 250 kb/s, 500 kb/s, 1 Mbps — message timing should match manufacturer spec
- Message parameters to monitor: expected message ID(s), signal frequency/cycle time, data length, checksum/CRC validity
Diagnostic algorithm
- Retrieve and record all DTCs and freeze frame data from all modules. Note time/conditions and any related U or P codes.
- Verify battery state of charge and charging system (low voltage can corrupt communications). Repair charging/battery faults first.
- Visually inspect connectors and wiring on affected modules and along the main data bus. Repair any damaged or corroded connectors.
- With a professional scan tool, observe bus traffic: verify presence, frequency and content of expected messages from the suspected sender(s).
- Measure CAN_H and CAN_L voltages with key on, engine off; then while communicating. Confirm differential amplitude is within expected range.
- Check bus termination resistance between CAN_H and CAN_L at key points (should be ≈60 Ω across the bus). Replace missing/failed terminators.
Likely causes
- Damaged wiring or loose connector on the vehicle data bus
- One module is malfunctioning and sending corrupted messages
- Battery/alternator voltage out of specification causing communication errors
- Failed or missing CAN bus termination resistor(s)
- Software update required or incorrect module flash
Fault status
Status
Invalid data received on the vehicle network. Check network wiring, module communication, power/ground and module software before replacing modules.
Repair difficulty: Medium
Diagnostic time: 1.0-3.5 hours
HTML Workshop Manuals AI manual library for LAND ROVER Click to show available manuals 1
LAND ROVER 2015 Discovery Sport HSE
HTML ManualWorkshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
