Code
U2101
Generic
U — Network/User
Invalid Data Received From Control Module
Views:
UK: 6
EN: 2
RU: 4
AI status
Completed
Completed
100%
Causes
- Corroded, loose, or damaged connectors or wiring on the vehicle communication bus (CAN, LIN, FlexRay, MOST, etc.)
- Shorted or open communication pair (CAN_H/CAN_L) or intermittent connection
- Failed or failing control module sending corrupted or out-of-spec messages
- Incorrect software/calibration version or configuration mismatch between modules
- High bus error/dropout rate due to excessive bus load or electrical noise
- Missing or incorrect termination resistor(s) on the communication bus
Symptoms
- One or more modules display communication-related fault codes or warnings
- Intermittent or permanent loss of function for systems dependent on the affected module(s)
- Illumination of warning lamps (MIL, ABS, traction, airbag, etc.) or multiple lamp combinations
- Erratic or incorrect dashboard information (speed, gear, warnings) from other modules
- Reduced vehicle drivability or limp mode if critical powertrain messages are invalid
- Noisy or garbled messages visible when scanning network traffic with a bus analyzer
What to check
- Read all U-codes and related manufacturer-specific codes from every module — note freeze frame data and time stamps
- Inspect for any Technical Service Bulletins (TSBs) or software updates for network-related issues
- Visually inspect connectors and wiring for corrosion, bent pins, water intrusion, or damage
- Verify battery voltage and module supply/ground integrity at suspected modules
- Check for other active communication bus faults (bus-off, error counters) reported by modules
- Measure termination resistance across the communication pair with ignition off (approx. 60 ohms for CAN)
Signal parameters
- Message ID / PGN of the corrupted or unexpected message
- Message frequency (expected vs actual update rate)
- Message length (expected DLC) and payload format
- Checksum or CRC fields (if applicable) and computed integrity
- CAN bus voltages: CAN_H and CAN_L idle and dominant levels (checked with oscilloscope)
- Differential waveform shape and amplitude, presence of reflections or noise
Diagnostic algorithm
- Record all stored codes and freeze frame data from every module. Do not clear codes yet unless instructed by a repair procedure.
- Identify which module(s) reported the U2101 and which module(s) were the source/sender of the invalid data (scan tool network messages and message IDs).
- Visually inspect connectors, pins and wiring for the implicated modules and along the network trunk/branches. Repair any corrosion, broken wires, or poor crimps.
- Verify battery voltage and good chassis/engine/ground connections. Low or noisy supply can corrupt messages.
- With a capable scan tool or CAN/LIN analyzer capture live bus traffic. Look for malformed frames, abnormal timing, missing messages, CRC failures, repeated arbitration losses or bus error spikes.
- Use an oscilloscope to check CAN_H/CAN_L waveforms at multiple points: verify differential signal integrity, absence of excessive reflections, and proper recessive/dominant levels.
- Measure termination resistance across the communication pair with ignition off (two 120 ohm resistors in parallel ≈ 60 ohms on CAN). Replace missing/incorrect terms.
- If a single module is identified as transmitting invalid data, confirm its software/calibration level and compare to known-good spec or TSBs. Reflash or update software if a newer calibration addresses communication errors.
- Isolate the network segment by disconnecting non-essential nodes/modules one at a time while monitoring the bus to see when errors cease — this helps identify a faulty module or add-on device.
- Replace the faulty module only after confirming through isolation and network captures that the module is the cause. After replacement or repair, reprogram to correct software, clear codes, and road-test to verify the fault does not return.
- If intermittent issues persist, perform extended network logging under conditions where the symptom occurs (cold start, vibration, wet conditions, etc.).
Likely causes
- Damaged wiring or poor connector/ground at the module(s) associated with reported messages
- Intermittent bus short/ground or loose connector causing packet corruption
- One module transmitting malformed messages due to internal fault or corrupted firmware
- Bus termination missing or incorrect causing reflections and corrupted frames
- Software/flash mismatch after an incomplete or incorrect reprogramming event
Fault status
Status
Invalid data or malformed messages were received from another control module on the vehicle communication network. This indicates data integrity or network communication problems that may affect multiple systems.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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Code
U2101
LAND ROVER
U — Network/User
Incompatible control module configuration
Views:
UK: 10
EN: 12
RU: 10
AI status
Completed
Completed
100%
Causes
- Corroded, loose, or damaged connectors or wiring on the vehicle communication bus (CAN, LIN, FlexRay, MOST, etc.)
- Shorted or open communication pair (CAN_H/CAN_L) or intermittent connection
- Failed or failing control module sending corrupted or out-of-spec messages
- Incorrect software/calibration version or configuration mismatch between modules
- High bus error/dropout rate due to excessive bus load or electrical noise
- Missing or incorrect termination resistor(s) on the communication bus
Symptoms
- One or more modules display communication-related fault codes or warnings
- Intermittent or permanent loss of function for systems dependent on the affected module(s)
- Illumination of warning lamps (MIL, ABS, traction, airbag, etc.) or multiple lamp combinations
- Erratic or incorrect dashboard information (speed, gear, warnings) from other modules
- Reduced vehicle drivability or limp mode if critical powertrain messages are invalid
- Noisy or garbled messages visible when scanning network traffic with a bus analyzer
What to check
- Read all U-codes and related manufacturer-specific codes from every module — note freeze frame data and time stamps
- Inspect for any Technical Service Bulletins (TSBs) or software updates for network-related issues
- Visually inspect connectors and wiring for corrosion, bent pins, water intrusion, or damage
- Verify battery voltage and module supply/ground integrity at suspected modules
- Check for other active communication bus faults (bus-off, error counters) reported by modules
- Measure termination resistance across the communication pair with ignition off (approx. 60 ohms for CAN)
Signal parameters
- Message ID / PGN of the corrupted or unexpected message
- Message frequency (expected vs actual update rate)
- Message length (expected DLC) and payload format
- Checksum or CRC fields (if applicable) and computed integrity
- CAN bus voltages: CAN_H and CAN_L idle and dominant levels (checked with oscilloscope)
- Differential waveform shape and amplitude, presence of reflections or noise
Diagnostic algorithm
- Record all stored codes and freeze frame data from every module. Do not clear codes yet unless instructed by a repair procedure.
- Identify which module(s) reported the U2101 and which module(s) were the source/sender of the invalid data (scan tool network messages and message IDs).
- Visually inspect connectors, pins and wiring for the implicated modules and along the network trunk/branches. Repair any corrosion, broken wires, or poor crimps.
- Verify battery voltage and good chassis/engine/ground connections. Low or noisy supply can corrupt messages.
- With a capable scan tool or CAN/LIN analyzer capture live bus traffic. Look for malformed frames, abnormal timing, missing messages, CRC failures, repeated arbitration losses or bus error spikes.
- Use an oscilloscope to check CAN_H/CAN_L waveforms at multiple points: verify differential signal integrity, absence of excessive reflections, and proper recessive/dominant levels.
- Measure termination resistance across the communication pair with ignition off (two 120 ohm resistors in parallel ≈ 60 ohms on CAN). Replace missing/incorrect terms.
- If a single module is identified as transmitting invalid data, confirm its software/calibration level and compare to known-good spec or TSBs. Reflash or update software if a newer calibration addresses communication errors.
- Isolate the network segment by disconnecting non-essential nodes/modules one at a time while monitoring the bus to see when errors cease — this helps identify a faulty module or add-on device.
- Replace the faulty module only after confirming through isolation and network captures that the module is the cause. After replacement or repair, reprogram to correct software, clear codes, and road-test to verify the fault does not return.
- If intermittent issues persist, perform extended network logging under conditions where the symptom occurs (cold start, vibration, wet conditions, etc.).
Likely causes
- Damaged wiring or poor connector/ground at the module(s) associated with reported messages
- Intermittent bus short/ground or loose connector causing packet corruption
- One module transmitting malformed messages due to internal fault or corrupted firmware
- Bus termination missing or incorrect causing reflections and corrupted frames
- Software/flash mismatch after an incomplete or incorrect reprogramming event
Fault status
Status
Invalid data or malformed messages were received from another control module on the vehicle communication network. This indicates data integrity or network communication problems that may affect multiple systems.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
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Send to email
Code
U2101
OPEL
U — Network/User
CAN-Bus Maximum Configuration List not Programmed
Views:
UK: 8
EN: 6
RU: 6
AI status
Completed
Completed
100%
Causes
- Corroded, loose, or damaged connectors or wiring on the vehicle communication bus (CAN, LIN, FlexRay, MOST, etc.)
- Shorted or open communication pair (CAN_H/CAN_L) or intermittent connection
- Failed or failing control module sending corrupted or out-of-spec messages
- Incorrect software/calibration version or configuration mismatch between modules
- High bus error/dropout rate due to excessive bus load or electrical noise
- Missing or incorrect termination resistor(s) on the communication bus
Symptoms
- One or more modules display communication-related fault codes or warnings
- Intermittent or permanent loss of function for systems dependent on the affected module(s)
- Illumination of warning lamps (MIL, ABS, traction, airbag, etc.) or multiple lamp combinations
- Erratic or incorrect dashboard information (speed, gear, warnings) from other modules
- Reduced vehicle drivability or limp mode if critical powertrain messages are invalid
- Noisy or garbled messages visible when scanning network traffic with a bus analyzer
What to check
- Read all U-codes and related manufacturer-specific codes from every module — note freeze frame data and time stamps
- Inspect for any Technical Service Bulletins (TSBs) or software updates for network-related issues
- Visually inspect connectors and wiring for corrosion, bent pins, water intrusion, or damage
- Verify battery voltage and module supply/ground integrity at suspected modules
- Check for other active communication bus faults (bus-off, error counters) reported by modules
- Measure termination resistance across the communication pair with ignition off (approx. 60 ohms for CAN)
Signal parameters
- Message ID / PGN of the corrupted or unexpected message
- Message frequency (expected vs actual update rate)
- Message length (expected DLC) and payload format
- Checksum or CRC fields (if applicable) and computed integrity
- CAN bus voltages: CAN_H and CAN_L idle and dominant levels (checked with oscilloscope)
- Differential waveform shape and amplitude, presence of reflections or noise
Diagnostic algorithm
- Record all stored codes and freeze frame data from every module. Do not clear codes yet unless instructed by a repair procedure.
- Identify which module(s) reported the U2101 and which module(s) were the source/sender of the invalid data (scan tool network messages and message IDs).
- Visually inspect connectors, pins and wiring for the implicated modules and along the network trunk/branches. Repair any corrosion, broken wires, or poor crimps.
- Verify battery voltage and good chassis/engine/ground connections. Low or noisy supply can corrupt messages.
- With a capable scan tool or CAN/LIN analyzer capture live bus traffic. Look for malformed frames, abnormal timing, missing messages, CRC failures, repeated arbitration losses or bus error spikes.
- Use an oscilloscope to check CAN_H/CAN_L waveforms at multiple points: verify differential signal integrity, absence of excessive reflections, and proper recessive/dominant levels.
- Measure termination resistance across the communication pair with ignition off (two 120 ohm resistors in parallel ≈ 60 ohms on CAN). Replace missing/incorrect terms.
- If a single module is identified as transmitting invalid data, confirm its software/calibration level and compare to known-good spec or TSBs. Reflash or update software if a newer calibration addresses communication errors.
- Isolate the network segment by disconnecting non-essential nodes/modules one at a time while monitoring the bus to see when errors cease — this helps identify a faulty module or add-on device.
- Replace the faulty module only after confirming through isolation and network captures that the module is the cause. After replacement or repair, reprogram to correct software, clear codes, and road-test to verify the fault does not return.
- If intermittent issues persist, perform extended network logging under conditions where the symptom occurs (cold start, vibration, wet conditions, etc.).
Likely causes
- Damaged wiring or poor connector/ground at the module(s) associated with reported messages
- Intermittent bus short/ground or loose connector causing packet corruption
- One module transmitting malformed messages due to internal fault or corrupted firmware
- Bus termination missing or incorrect causing reflections and corrupted frames
- Software/flash mismatch after an incomplete or incorrect reprogramming event
Fault status
Status
Invalid data or malformed messages were received from another control module on the vehicle communication network. This indicates data integrity or network communication problems that may affect multiple systems.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
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