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Home / DTC / U0403 — Invalid Data Received From Transfer Case Control Module

U0403 — Invalid Data Received From Transfer Case Control Module

Detailed page for trouble code U0403.

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U0403

Generic U — Network/User

Invalid Data Received From Transfer Case Control Module

Brand: Generic
Type: U — Network/User
Views: UK: 22 EN: 88 RU: 28
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Poor or missing power/ground to the transfer case control module
  • Corroded, loose, or damaged connectors or wiring in the transfer case harness
  • Faulty Transfer Case Control Module (TCCM) producing invalid messages
  • Intermittent or failed CAN/LIN network (open, short, high resistance, or bridging)
  • Software mismatch or corrupted module programming (incompatible calibration)
  • Another module transmitting bad data, causing the receiving controller to flag the TCCM data as invalid

Symptoms

  • Malfunction Indicator Lamp (MIL) or AWD/4WD warning lamp illuminated
  • 4WD/AWD system disabled, stuck in one drive mode, or fails to shift transfer case
  • Incorrect or no transfer case status shown on dash (mode indicator may be wrong)
  • Loss of related functionality (traction control, stability/torque distribution warnings)
  • Intermittent or persistent communication-related DTCs present
  • Possible limp/default transfer case behavior

What to check

  • Read and record all stored DTCs and freeze-frame data from all modules (powertrain, ABS, BCM, transfer case)
  • Check battery voltage and charging system; ensure battery >12.4V at rest during tests
  • Inspect fuses and relays supplying the TCCM and vehicle network
  • Visually inspect TCCM connector and wiring for corrosion, damaged pins, crushed wiring, rodent damage or moisture
  • Check for recent service or module replacement that may require reprogramming/coding
  • Check for other U0xxx or U01xx codes that indicate network-wide issues

Signal parameters

  • CAN High idle ≈ 2.5V–3.5V; dominant state ≈ 3.5V (vehicle dependent)
  • CAN Low idle ≈ 2.5V–1.5V; dominant state ≈ 1.5V (vehicle dependent)
  • Expected CAN differential idle ≈ 0V (balanced ~2.5V each), differential when dominant ≈ 2V
  • TCCM message frequency and CAN ID vary by make/model; expected periodic transfer-case-status messages when vehicle is on
  • Typical transfer-case status payload: mode/requested-mode, motor position, clutch engagement, fault bits (values and encoding vary by manufacturer)

Diagnostic algorithm

  1. Capture and record all related DTCs and freeze-frame data; note whether code is active or historic.
  2. Verify battery voltage and check charging system; low voltage can corrupt communications. Charge battery if needed and retest.
  3. Inspect TCCM power, ground and the related fuses/relays for continuity and correct voltage with key ON and engine running.
  4. Visually inspect the transfer case module connector and harness for damage, corrosion, or bent pins; repair any issues and reseat connectors.
  5. Use a scan tool to query the TCCM and neighboring modules for presence, response time, and data plausibility. Note any modules not responding.
  6. Check network voltages at the TCCM connector: measure CANH and CANL idle voltages and compare to other known-good modules. Look for short to battery/ground.
  7. If intermittent, wiggle test harness and connectors while monitoring communications; if failure reproduces, repair wiring/connector.
  8. If improper voltages or bus errors are present, isolate sections of the CAN bus (disconnect modules one at a time per service manual) to locate short/open component.
  9. If the TCCM does not respond or sends corrupt frames but wiring and power/ground are good, check for recent reprogramming or software mismatch; update module software/calibration per OEM procedures.
  10. If bench/known-good module available, swap (or bench-test) TCCM to verify behavior before module replacement. Re-test after any repair and clear codes; perform road test to confirm.
  11. If code persists after verifying wiring, power, network and software, follow manufacturer-specific procedures for module replacement and coding.

Likely causes

  • Open/short/poor pin contact at TCCM connector
  • Low battery or unstable supply voltage to modules
  • Defective TCCM hardware or internal memory corruption
  • Damaged CAN bus (short to battery/ground) near transfer case module
  • Recent module replacement without correct reprogramming or coding

Fault status

⚠️ Status
Controller received invalid or corrupted data from the Transfer Case Control Module over the vehicle network; transfer case/4WD functionality may be affected.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

U0100 U0121 U0140 U0401 U0402 U0415
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Code

U0403

HYUNDAI U — Network/User

Invalid Data Received From Transfer Case Control Module

Brand: HYUNDAI
Type: U — Network/User
Views: UK: 18 EN: 77 RU: 23
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Poor or missing power/ground to the transfer case control module
  • Corroded, loose, or damaged connectors or wiring in the transfer case harness
  • Faulty Transfer Case Control Module (TCCM) producing invalid messages
  • Intermittent or failed CAN/LIN network (open, short, high resistance, or bridging)
  • Software mismatch or corrupted module programming (incompatible calibration)
  • Another module transmitting bad data, causing the receiving controller to flag the TCCM data as invalid

Symptoms

  • Malfunction Indicator Lamp (MIL) or AWD/4WD warning lamp illuminated
  • 4WD/AWD system disabled, stuck in one drive mode, or fails to shift transfer case
  • Incorrect or no transfer case status shown on dash (mode indicator may be wrong)
  • Loss of related functionality (traction control, stability/torque distribution warnings)
  • Intermittent or persistent communication-related DTCs present
  • Possible limp/default transfer case behavior

What to check

  • Read and record all stored DTCs and freeze-frame data from all modules (powertrain, ABS, BCM, transfer case)
  • Check battery voltage and charging system; ensure battery >12.4V at rest during tests
  • Inspect fuses and relays supplying the TCCM and vehicle network
  • Visually inspect TCCM connector and wiring for corrosion, damaged pins, crushed wiring, rodent damage or moisture
  • Check for recent service or module replacement that may require reprogramming/coding
  • Check for other U0xxx or U01xx codes that indicate network-wide issues

Signal parameters

  • CAN High idle ≈ 2.5V–3.5V; dominant state ≈ 3.5V (vehicle dependent)
  • CAN Low idle ≈ 2.5V–1.5V; dominant state ≈ 1.5V (vehicle dependent)
  • Expected CAN differential idle ≈ 0V (balanced ~2.5V each), differential when dominant ≈ 2V
  • TCCM message frequency and CAN ID vary by make/model; expected periodic transfer-case-status messages when vehicle is on
  • Typical transfer-case status payload: mode/requested-mode, motor position, clutch engagement, fault bits (values and encoding vary by manufacturer)

Diagnostic algorithm

  1. Capture and record all related DTCs and freeze-frame data; note whether code is active or historic.
  2. Verify battery voltage and check charging system; low voltage can corrupt communications. Charge battery if needed and retest.
  3. Inspect TCCM power, ground and the related fuses/relays for continuity and correct voltage with key ON and engine running.
  4. Visually inspect the transfer case module connector and harness for damage, corrosion, or bent pins; repair any issues and reseat connectors.
  5. Use a scan tool to query the TCCM and neighboring modules for presence, response time, and data plausibility. Note any modules not responding.
  6. Check network voltages at the TCCM connector: measure CANH and CANL idle voltages and compare to other known-good modules. Look for short to battery/ground.
  7. If intermittent, wiggle test harness and connectors while monitoring communications; if failure reproduces, repair wiring/connector.
  8. If improper voltages or bus errors are present, isolate sections of the CAN bus (disconnect modules one at a time per service manual) to locate short/open component.
  9. If the TCCM does not respond or sends corrupt frames but wiring and power/ground are good, check for recent reprogramming or software mismatch; update module software/calibration per OEM procedures.
  10. If bench/known-good module available, swap (or bench-test) TCCM to verify behavior before module replacement. Re-test after any repair and clear codes; perform road test to confirm.
  11. If code persists after verifying wiring, power, network and software, follow manufacturer-specific procedures for module replacement and coding.

Likely causes

  • Open/short/poor pin contact at TCCM connector
  • Low battery or unstable supply voltage to modules
  • Defective TCCM hardware or internal memory corruption
  • Damaged CAN bus (short to battery/ground) near transfer case module
  • Recent module replacement without correct reprogramming or coding

Fault status

⚠️ Status
Controller received invalid or corrupted data from the Transfer Case Control Module over the vehicle network; transfer case/4WD functionality may be affected.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

U0100 U0121 U0140 U0401 U0402 U0415
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

U0403

LAND ROVER U — Network/User

Invalid data received from the transfer box control module

Brand: LAND ROVER
Type: U — Network/User
Views: UK: 11 EN: 27 RU: 13
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Poor or missing power/ground to the transfer case control module
  • Corroded, loose, or damaged connectors or wiring in the transfer case harness
  • Faulty Transfer Case Control Module (TCCM) producing invalid messages
  • Intermittent or failed CAN/LIN network (open, short, high resistance, or bridging)
  • Software mismatch or corrupted module programming (incompatible calibration)
  • Another module transmitting bad data, causing the receiving controller to flag the TCCM data as invalid

Symptoms

  • Malfunction Indicator Lamp (MIL) or AWD/4WD warning lamp illuminated
  • 4WD/AWD system disabled, stuck in one drive mode, or fails to shift transfer case
  • Incorrect or no transfer case status shown on dash (mode indicator may be wrong)
  • Loss of related functionality (traction control, stability/torque distribution warnings)
  • Intermittent or persistent communication-related DTCs present
  • Possible limp/default transfer case behavior

What to check

  • Read and record all stored DTCs and freeze-frame data from all modules (powertrain, ABS, BCM, transfer case)
  • Check battery voltage and charging system; ensure battery >12.4V at rest during tests
  • Inspect fuses and relays supplying the TCCM and vehicle network
  • Visually inspect TCCM connector and wiring for corrosion, damaged pins, crushed wiring, rodent damage or moisture
  • Check for recent service or module replacement that may require reprogramming/coding
  • Check for other U0xxx or U01xx codes that indicate network-wide issues

Signal parameters

  • CAN High idle ≈ 2.5V–3.5V; dominant state ≈ 3.5V (vehicle dependent)
  • CAN Low idle ≈ 2.5V–1.5V; dominant state ≈ 1.5V (vehicle dependent)
  • Expected CAN differential idle ≈ 0V (balanced ~2.5V each), differential when dominant ≈ 2V
  • TCCM message frequency and CAN ID vary by make/model; expected periodic transfer-case-status messages when vehicle is on
  • Typical transfer-case status payload: mode/requested-mode, motor position, clutch engagement, fault bits (values and encoding vary by manufacturer)

Diagnostic algorithm

  1. Capture and record all related DTCs and freeze-frame data; note whether code is active or historic.
  2. Verify battery voltage and check charging system; low voltage can corrupt communications. Charge battery if needed and retest.
  3. Inspect TCCM power, ground and the related fuses/relays for continuity and correct voltage with key ON and engine running.
  4. Visually inspect the transfer case module connector and harness for damage, corrosion, or bent pins; repair any issues and reseat connectors.
  5. Use a scan tool to query the TCCM and neighboring modules for presence, response time, and data plausibility. Note any modules not responding.
  6. Check network voltages at the TCCM connector: measure CANH and CANL idle voltages and compare to other known-good modules. Look for short to battery/ground.
  7. If intermittent, wiggle test harness and connectors while monitoring communications; if failure reproduces, repair wiring/connector.
  8. If improper voltages or bus errors are present, isolate sections of the CAN bus (disconnect modules one at a time per service manual) to locate short/open component.
  9. If the TCCM does not respond or sends corrupt frames but wiring and power/ground are good, check for recent reprogramming or software mismatch; update module software/calibration per OEM procedures.
  10. If bench/known-good module available, swap (or bench-test) TCCM to verify behavior before module replacement. Re-test after any repair and clear codes; perform road test to confirm.
  11. If code persists after verifying wiring, power, network and software, follow manufacturer-specific procedures for module replacement and coding.

Likely causes

  • Open/short/poor pin contact at TCCM connector
  • Low battery or unstable supply voltage to modules
  • Defective TCCM hardware or internal memory corruption
  • Damaged CAN bus (short to battery/ground) near transfer case module
  • Recent module replacement without correct reprogramming or coding

Fault status

⚠️ Status
Controller received invalid or corrupted data from the Transfer Case Control Module over the vehicle network; transfer case/4WD functionality may be affected.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

U0100 U0121 U0140 U0401 U0402 U0415
Workshop Manuals

Repair manuals for LAND ROVER

3

Land Rover Defender 300Tdi — Workshop Manual (1996 model year)

Workshop Manual
Defender 300Tdi Years: 1996 Manual in English 7.5 MB
Short description

Official workshop manual for the Land Rover Defender 300Tdi (from 1996 model year). Contains specifications, adjustment, fault diagnosis and step-by-step repair and overhaul procedures for engine, transmission, axles, suspension, brakes, electrical and body. Intended for dealer workshops and trained technicians.

199,00 UAH
Contents
Key sections:
  • 01 INTRODUCTION
  • 04 GENERAL SPECIFICATION DATA
  • 05 ENGINE TUNING DATA
  • 07 GENERAL FITTING REMINDERS
  • 09 LUBRICANTS, FLUIDS AND CAPACITIES
  • 10 MAINTENANCE
  • 12 ENGINE Tdi
  • - Description and operation
  • - Fault diagnosis
  • - Adjustment
  • - Repair and overhaul procedures
  • 19 FUEL SYSTEM Tdi
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Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)

Workshop Manual
Defender Years: 1999–2002 Manual in English 7.6 MB
Short description

Workshop Manual Supplement and Body Repair Manual for the Land Rover Defender. Includes general specifications, maintenance schedules, tuning data and step‑by‑step repair procedures for engine, transmission, suspension, brakes, electrical and body repairs. Covers Defender models from 1999 and 2002 model years.

199,00 UAH
Contents
Key sections:
  • 01 - INTRODUCTION
  • - Introduction
  • - Dimensions
  • - References
  • - Repairs and replacements
  • - Poisonous substances
  • - Fuel handling precautions
  • - Synthetic rubber
  • - Recommended sealants
  • - Used engine oil precautions
  • - Accessories and conversions
  • - Wheels and tyres
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Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)

Workshop Manual
Manual in English Pages: 494 7.1 MB
Short description

Land Rover Range Rover Electrical Library (LRL 0453ENG). Comprehensive manual covering fuse details, earth points, system descriptions, diagnostics and connector pin-outs for electrical troubleshooting and repair. Intended for technicians and service workshops.

199,00 UAH
Contents
Key sections:
  • 1 INTRODUCTION
  • 1.1 About this document
  • 1.2 Battery voltage
  • 1.3 Electrical precautions
  • 1.4 Battery disconnecting / charging
  • 1.5 Disciplines / greases
  • 1.6 Abbreviations
  • 1.7 HeVAC, sensors abbreviations
  • 1.8 How to use this document
  • 1.9 Connector detail format
  • 1.10 Fault diagnosis
  • 1.11 Wire colour codes
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