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Home / DTC / U1602 — No message received from body computer via CAN bus

U1602 — No message received from body computer via CAN bus

Detailed page for trouble code U1602.

33,912codes
59brands
11,451generic
22,461specific
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Code

U1602

ALFA ROMEO U — Network/User

No message received from body computer via CAN bus

Brand: ALFA ROMEO
Type: U — Network/User
Views: UK: 33 EN: 30 RU: 33
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted CAN bus wiring between BC and other modules
  • Faulty or corroded connector at the body computer or intermediate junction
  • Body computer has no battery supply or ground
  • Blown fuse or relay feeding the body computer
  • Missing or incorrect CAN termination resistor(s)
  • Body computer held in sleep or not awake (software/wakeup issue)

Symptoms

  • Instrument cluster or dashboard warnings about network loss
  • Some body functions (central locking, lights, windows, alarms) inoperative or intermittent
  • Other modules report lost communication DTCs
  • Vehicle may not go into/exit certain modes (immobiliser, comfort functions)
  • Scan tool cannot communicate with the body computer while it can with other modules

What to check

  • Confirm U1602 and note any related U-codes with a scan tool (freeze frame, occurrence count)
  • Check all relevant fuses and relays feeding the body computer and the CAN bus
  • Visually inspect body computer connectors and CAN wiring for damage, corrosion, or loose pins
  • With ignition ON, attempt to communicate directly with the body computer using a scan tool
  • Measure CAN bus voltages at an accessible connector with key ON: CAN_H and CAN_L should be ~2.5 V (recessive)
  • Measure DC supply and ground at the body computer connector (battery voltage and solid ground)

Signal parameters

  • Recessive idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
  • Dominant state typical: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2 V)
  • Bus differential amplitude: ≈ 2 V when dominant
  • Typical bus impedance: ≈ 60 Ω (two 120 Ω terminators in parallel)
  • Common bus bitrates: 250 kbps or 500 kbps (verify vehicle-specific rate)
  • Body computer message rate: varies by message — from

Diagnostic algorithm

  1. Retrieve and record U1602 plus any other live codes and freeze frame data with a scan tool.
  2. Verify whether the scan tool can communicate with other modules. If all communication is lost, suspect bus-wide power/ground or a main trunk fault.
  3. Inspect fuses and relays that supply power to the body computer; restore any blown fuses and retest.
  4. Visually inspect the body computer connectors and nearby harness for damage, corrosion, or pushed-out pins. Repair as necessary.
  5. With ignition ON, check battery voltage at the body computer power pin(s) and verify good ground(s). Repair low voltage or ground faults.
  6. Check CAN bus idle voltages at a convenient connector (not at the module if it is suspected dead). Recessive voltages should be ≈2.5 V. If voltages are incorrect, trace back to power/ground or short.
  7. Disconnect the body computer connector (with battery disconnected if required by vehicle procedures) and measure resistance between CAN_H and CAN_L at the harness — expect ~60 Ω. If not ≈60 Ω, check for missing terminator or short/open elsewhere.
  8. Check for short to battery or ground from each CAN line to chassis/battery using an ohmmeter/voltage check. Repair wiring faults.
  9. Use an oscilloscope to view CAN_H/CAN_L waveform. Look for noise, missing dominant bits, or only recessive states indicating no transmitter.
  10. If wiring and power/ground are correct but no messages are present from the BC, attempt module reset or reflash per OEM procedures. If reprogramming not possible or fails, replacement of the body computer may be required.
  11. After repair, clear codes and verify restored communication and normal function; road test to confirm intermittent faults are resolved.

Likely causes

  • Blown fuse or bad power/ground to the body computer
  • Damaged or loose connector at the body computer harness
  • Short to battery or ground on CAN_H or CAN_L in the BC segment
  • Missing/failed termination at one end of the CAN network
  • Body computer software/firmware hang or failed module

Fault status

⚠️ Status
No message received from body computer via CAN bus (lost communication with Body Computer).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0100 U0121 U0155 U0073 U1000
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Code

U1602

FIAT U — Network/User

No message received from body computer via CAN bus

Brand: FIAT
Type: U — Network/User
Views: UK: 27 EN: 29 RU: 26
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted CAN bus wiring between BC and other modules
  • Faulty or corroded connector at the body computer or intermediate junction
  • Body computer has no battery supply or ground
  • Blown fuse or relay feeding the body computer
  • Missing or incorrect CAN termination resistor(s)
  • Body computer held in sleep or not awake (software/wakeup issue)

Symptoms

  • Instrument cluster or dashboard warnings about network loss
  • Some body functions (central locking, lights, windows, alarms) inoperative or intermittent
  • Other modules report lost communication DTCs
  • Vehicle may not go into/exit certain modes (immobiliser, comfort functions)
  • Scan tool cannot communicate with the body computer while it can with other modules

What to check

  • Confirm U1602 and note any related U-codes with a scan tool (freeze frame, occurrence count)
  • Check all relevant fuses and relays feeding the body computer and the CAN bus
  • Visually inspect body computer connectors and CAN wiring for damage, corrosion, or loose pins
  • With ignition ON, attempt to communicate directly with the body computer using a scan tool
  • Measure CAN bus voltages at an accessible connector with key ON: CAN_H and CAN_L should be ~2.5 V (recessive)
  • Measure DC supply and ground at the body computer connector (battery voltage and solid ground)

Signal parameters

  • Recessive idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
  • Dominant state typical: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2 V)
  • Bus differential amplitude: ≈ 2 V when dominant
  • Typical bus impedance: ≈ 60 Ω (two 120 Ω terminators in parallel)
  • Common bus bitrates: 250 kbps or 500 kbps (verify vehicle-specific rate)
  • Body computer message rate: varies by message — from

Diagnostic algorithm

  1. Retrieve and record U1602 plus any other live codes and freeze frame data with a scan tool.
  2. Verify whether the scan tool can communicate with other modules. If all communication is lost, suspect bus-wide power/ground or a main trunk fault.
  3. Inspect fuses and relays that supply power to the body computer; restore any blown fuses and retest.
  4. Visually inspect the body computer connectors and nearby harness for damage, corrosion, or pushed-out pins. Repair as necessary.
  5. With ignition ON, check battery voltage at the body computer power pin(s) and verify good ground(s). Repair low voltage or ground faults.
  6. Check CAN bus idle voltages at a convenient connector (not at the module if it is suspected dead). Recessive voltages should be ≈2.5 V. If voltages are incorrect, trace back to power/ground or short.
  7. Disconnect the body computer connector (with battery disconnected if required by vehicle procedures) and measure resistance between CAN_H and CAN_L at the harness — expect ~60 Ω. If not ≈60 Ω, check for missing terminator or short/open elsewhere.
  8. Check for short to battery or ground from each CAN line to chassis/battery using an ohmmeter/voltage check. Repair wiring faults.
  9. Use an oscilloscope to view CAN_H/CAN_L waveform. Look for noise, missing dominant bits, or only recessive states indicating no transmitter.
  10. If wiring and power/ground are correct but no messages are present from the BC, attempt module reset or reflash per OEM procedures. If reprogramming not possible or fails, replacement of the body computer may be required.
  11. After repair, clear codes and verify restored communication and normal function; road test to confirm intermittent faults are resolved.

Likely causes

  • Blown fuse or bad power/ground to the body computer
  • Damaged or loose connector at the body computer harness
  • Short to battery or ground on CAN_H or CAN_L in the BC segment
  • Missing/failed termination at one end of the CAN network
  • Body computer software/firmware hang or failed module

Fault status

⚠️ Status
No message received from body computer via CAN bus (lost communication with Body Computer).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0100 U0121 U0155 U0073 U1000
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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

U1602

Generic U — Network/User

Invalid Data Received From Control Module

Brand: Generic
Type: U — Network/User
Views: UK: 21 EN: 23 RU: 17
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted CAN bus wiring between BC and other modules
  • Faulty or corroded connector at the body computer or intermediate junction
  • Body computer has no battery supply or ground
  • Blown fuse or relay feeding the body computer
  • Missing or incorrect CAN termination resistor(s)
  • Body computer held in sleep or not awake (software/wakeup issue)

Symptoms

  • Instrument cluster or dashboard warnings about network loss
  • Some body functions (central locking, lights, windows, alarms) inoperative or intermittent
  • Other modules report lost communication DTCs
  • Vehicle may not go into/exit certain modes (immobiliser, comfort functions)
  • Scan tool cannot communicate with the body computer while it can with other modules

What to check

  • Confirm U1602 and note any related U-codes with a scan tool (freeze frame, occurrence count)
  • Check all relevant fuses and relays feeding the body computer and the CAN bus
  • Visually inspect body computer connectors and CAN wiring for damage, corrosion, or loose pins
  • With ignition ON, attempt to communicate directly with the body computer using a scan tool
  • Measure CAN bus voltages at an accessible connector with key ON: CAN_H and CAN_L should be ~2.5 V (recessive)
  • Measure DC supply and ground at the body computer connector (battery voltage and solid ground)

Signal parameters

  • Recessive idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
  • Dominant state typical: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2 V)
  • Bus differential amplitude: ≈ 2 V when dominant
  • Typical bus impedance: ≈ 60 Ω (two 120 Ω terminators in parallel)
  • Common bus bitrates: 250 kbps or 500 kbps (verify vehicle-specific rate)
  • Body computer message rate: varies by message — from

Diagnostic algorithm

  1. Retrieve and record U1602 plus any other live codes and freeze frame data with a scan tool.
  2. Verify whether the scan tool can communicate with other modules. If all communication is lost, suspect bus-wide power/ground or a main trunk fault.
  3. Inspect fuses and relays that supply power to the body computer; restore any blown fuses and retest.
  4. Visually inspect the body computer connectors and nearby harness for damage, corrosion, or pushed-out pins. Repair as necessary.
  5. With ignition ON, check battery voltage at the body computer power pin(s) and verify good ground(s). Repair low voltage or ground faults.
  6. Check CAN bus idle voltages at a convenient connector (not at the module if it is suspected dead). Recessive voltages should be ≈2.5 V. If voltages are incorrect, trace back to power/ground or short.
  7. Disconnect the body computer connector (with battery disconnected if required by vehicle procedures) and measure resistance between CAN_H and CAN_L at the harness — expect ~60 Ω. If not ≈60 Ω, check for missing terminator or short/open elsewhere.
  8. Check for short to battery or ground from each CAN line to chassis/battery using an ohmmeter/voltage check. Repair wiring faults.
  9. Use an oscilloscope to view CAN_H/CAN_L waveform. Look for noise, missing dominant bits, or only recessive states indicating no transmitter.
  10. If wiring and power/ground are correct but no messages are present from the BC, attempt module reset or reflash per OEM procedures. If reprogramming not possible or fails, replacement of the body computer may be required.
  11. After repair, clear codes and verify restored communication and normal function; road test to confirm intermittent faults are resolved.

Likely causes

  • Blown fuse or bad power/ground to the body computer
  • Damaged or loose connector at the body computer harness
  • Short to battery or ground on CAN_H or CAN_L in the BC segment
  • Missing/failed termination at one end of the CAN network
  • Body computer software/firmware hang or failed module

Fault status

⚠️ Status
No message received from body computer via CAN bus (lost communication with Body Computer).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0100 U0121 U0155 U0073 U1000
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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
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Code

U1602

HYUNDAI U — Network/User

Data Upgrade Error - Application Software Code 2 Missing or Corrupted

Brand: HYUNDAI
Type: U — Network/User
Views: UK: 40 EN: 45 RU: 30
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or shorted CAN bus wiring between BC and other modules
  • Faulty or corroded connector at the body computer or intermediate junction
  • Body computer has no battery supply or ground
  • Blown fuse or relay feeding the body computer
  • Missing or incorrect CAN termination resistor(s)
  • Body computer held in sleep or not awake (software/wakeup issue)

Symptoms

  • Instrument cluster or dashboard warnings about network loss
  • Some body functions (central locking, lights, windows, alarms) inoperative or intermittent
  • Other modules report lost communication DTCs
  • Vehicle may not go into/exit certain modes (immobiliser, comfort functions)
  • Scan tool cannot communicate with the body computer while it can with other modules

What to check

  • Confirm U1602 and note any related U-codes with a scan tool (freeze frame, occurrence count)
  • Check all relevant fuses and relays feeding the body computer and the CAN bus
  • Visually inspect body computer connectors and CAN wiring for damage, corrosion, or loose pins
  • With ignition ON, attempt to communicate directly with the body computer using a scan tool
  • Measure CAN bus voltages at an accessible connector with key ON: CAN_H and CAN_L should be ~2.5 V (recessive)
  • Measure DC supply and ground at the body computer connector (battery voltage and solid ground)

Signal parameters

  • Recessive idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
  • Dominant state typical: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2 V)
  • Bus differential amplitude: ≈ 2 V when dominant
  • Typical bus impedance: ≈ 60 Ω (two 120 Ω terminators in parallel)
  • Common bus bitrates: 250 kbps or 500 kbps (verify vehicle-specific rate)
  • Body computer message rate: varies by message — from

Diagnostic algorithm

  1. Retrieve and record U1602 plus any other live codes and freeze frame data with a scan tool.
  2. Verify whether the scan tool can communicate with other modules. If all communication is lost, suspect bus-wide power/ground or a main trunk fault.
  3. Inspect fuses and relays that supply power to the body computer; restore any blown fuses and retest.
  4. Visually inspect the body computer connectors and nearby harness for damage, corrosion, or pushed-out pins. Repair as necessary.
  5. With ignition ON, check battery voltage at the body computer power pin(s) and verify good ground(s). Repair low voltage or ground faults.
  6. Check CAN bus idle voltages at a convenient connector (not at the module if it is suspected dead). Recessive voltages should be ≈2.5 V. If voltages are incorrect, trace back to power/ground or short.
  7. Disconnect the body computer connector (with battery disconnected if required by vehicle procedures) and measure resistance between CAN_H and CAN_L at the harness — expect ~60 Ω. If not ≈60 Ω, check for missing terminator or short/open elsewhere.
  8. Check for short to battery or ground from each CAN line to chassis/battery using an ohmmeter/voltage check. Repair wiring faults.
  9. Use an oscilloscope to view CAN_H/CAN_L waveform. Look for noise, missing dominant bits, or only recessive states indicating no transmitter.
  10. If wiring and power/ground are correct but no messages are present from the BC, attempt module reset or reflash per OEM procedures. If reprogramming not possible or fails, replacement of the body computer may be required.
  11. After repair, clear codes and verify restored communication and normal function; road test to confirm intermittent faults are resolved.

Likely causes

  • Blown fuse or bad power/ground to the body computer
  • Damaged or loose connector at the body computer harness
  • Short to battery or ground on CAN_H or CAN_L in the BC segment
  • Missing/failed termination at one end of the CAN network
  • Body computer software/firmware hang or failed module

Fault status

⚠️ Status
No message received from body computer via CAN bus (lost communication with Body Computer).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0100 U0121 U0155 U0073 U1000
370

Browse 370 HYUNDAI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HYUNDAI

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
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