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Home / DTC / B2808 — No Response NM Message (CCP)

B2808 — No Response NM Message (CCP)

Detailed page for trouble code B2808.

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Code

B2808

HYUNDAI B — Body

No Response NM Message (CCP)

Brand: HYUNDAI
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty or unpowered control module (module did not wake or is non‑functional)
  • Blown fuse or lost supply/ground to the affected module
  • Open, shorted or corroded wiring or connector to the module
  • Bus wiring fault, poor termination or high electrical noise on the CCP/CAN network
  • Software mismatch, corrupted firmware, or incomplete module programming
  • Aftermarket device or recent repair that disturbed the network

Symptoms

  • Communication warnings or related system messages on the cluster
  • One or more vehicle systems inoperative or intermittent (those controlled by the unresponsive module)
  • Stored communication-related DTCs and possibly other dependent codes
  • No response when querying the module with a scan tool
  • Vehicle may fail to enter/exit sleep correctly or show wake/sleep faults

What to check

  • Read and record all DTCs and freeze frame data from all modules
  • Verify battery voltage and health; ensure stable supply (12.4–12.8 V with engine off)
  • Inspect fuses and relays for the affected module and BCM power circuits
  • Visual inspection of module connectors and wiring for corrosion, damage, or loose pins
  • Use a scan tool to attempt communication with the suspect module and watch for responses
  • Check for recent service, aftermarket devices or connectors that may affect the bus

Signal parameters

  • NM message presence: expected periodic NM/keepalive message ID and interval (compare to OEM spec)
  • Bus idle and dominant/recessive voltage levels (compare to OEM spec; for CAN typical recessive ~2.5 V common mode, CAN_H/CAN_L differential ≈0 V; dominant ~1.5 V differential)
  • Bus error counters and bus-off status reported by modules
  • Wake/sleep signals and voltage at module Vbat and ground during wake attempts
  • Message frequency and missing message count for the target ID

Diagnostic algorithm

  1. Capture and record all related DTCs and any freeze-frame data. Clear codes and attempt to reproduce; note whether code returns.
  2. Verify battery voltage and charging system. Low supply can prevent modules from responding.
  3. Check fuses/relays for the affected module and the main network/BCM supplies; replace if faulty.
  4. Perform a visual inspection of the module connector and wiring. Look for corrosion, bent pins, water intrusion or damage.
  5. With a scan tool, attempt to communicate with the module. If no response, check module Vbat and ground pins for correct voltages while attempting communication.
  6. Monitor the communication bus with a capable scan tool or oscilloscope. Verify presence of NM/keepalive messages and proper voltage/bit timing for the network. Compare to OEM specs.
  7. If bus noise or wiring faults are found, isolate segments (disconnect suspect module or aftermarket devices) and re-test to locate the fault. Check termination resistors where applicable.
  8. If wiring and supply are good but the module does not respond, check for software updates or reprogramming history. Reflash or reprogram per OEM procedure if available.
  9. If module is confirmed faulty after all checks, replace the module and perform required coding/initialization. Re-test entire network and clear codes.
  10. After repair, verify normal NM messaging and that no additional communication codes return. Document repairs and any replaced parts.

Likely causes

  • Failed or asleep target module (most likely)
  • Supply (fuse/relay) or ground problem preventing module operation
  • Local connector/wiring fault between module and network
  • Network-level fault (short, open, missing termination) affecting messages
  • Software/configuration problem after replacement or update

Fault status

⚠️ Status
No response to Network Management (NM) message on CCP bus — target control module did not reply to expected keepalive/wake message.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

U0100 U0073 U0121 B2799 B2800 B2810
371

Browse 371 HYUNDAI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HYUNDAI

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Code

B2808

LAND ROVER B — Body

Control Module Power Supply Fault

Brand: LAND ROVER
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty or unpowered control module (module did not wake or is non‑functional)
  • Blown fuse or lost supply/ground to the affected module
  • Open, shorted or corroded wiring or connector to the module
  • Bus wiring fault, poor termination or high electrical noise on the CCP/CAN network
  • Software mismatch, corrupted firmware, or incomplete module programming
  • Aftermarket device or recent repair that disturbed the network

Symptoms

  • Communication warnings or related system messages on the cluster
  • One or more vehicle systems inoperative or intermittent (those controlled by the unresponsive module)
  • Stored communication-related DTCs and possibly other dependent codes
  • No response when querying the module with a scan tool
  • Vehicle may fail to enter/exit sleep correctly or show wake/sleep faults

What to check

  • Read and record all DTCs and freeze frame data from all modules
  • Verify battery voltage and health; ensure stable supply (12.4–12.8 V with engine off)
  • Inspect fuses and relays for the affected module and BCM power circuits
  • Visual inspection of module connectors and wiring for corrosion, damage, or loose pins
  • Use a scan tool to attempt communication with the suspect module and watch for responses
  • Check for recent service, aftermarket devices or connectors that may affect the bus

Signal parameters

  • NM message presence: expected periodic NM/keepalive message ID and interval (compare to OEM spec)
  • Bus idle and dominant/recessive voltage levels (compare to OEM spec; for CAN typical recessive ~2.5 V common mode, CAN_H/CAN_L differential ≈0 V; dominant ~1.5 V differential)
  • Bus error counters and bus-off status reported by modules
  • Wake/sleep signals and voltage at module Vbat and ground during wake attempts
  • Message frequency and missing message count for the target ID

Diagnostic algorithm

  1. Capture and record all related DTCs and any freeze-frame data. Clear codes and attempt to reproduce; note whether code returns.
  2. Verify battery voltage and charging system. Low supply can prevent modules from responding.
  3. Check fuses/relays for the affected module and the main network/BCM supplies; replace if faulty.
  4. Perform a visual inspection of the module connector and wiring. Look for corrosion, bent pins, water intrusion or damage.
  5. With a scan tool, attempt to communicate with the module. If no response, check module Vbat and ground pins for correct voltages while attempting communication.
  6. Monitor the communication bus with a capable scan tool or oscilloscope. Verify presence of NM/keepalive messages and proper voltage/bit timing for the network. Compare to OEM specs.
  7. If bus noise or wiring faults are found, isolate segments (disconnect suspect module or aftermarket devices) and re-test to locate the fault. Check termination resistors where applicable.
  8. If wiring and supply are good but the module does not respond, check for software updates or reprogramming history. Reflash or reprogram per OEM procedure if available.
  9. If module is confirmed faulty after all checks, replace the module and perform required coding/initialization. Re-test entire network and clear codes.
  10. After repair, verify normal NM messaging and that no additional communication codes return. Document repairs and any replaced parts.

Likely causes

  • Failed or asleep target module (most likely)
  • Supply (fuse/relay) or ground problem preventing module operation
  • Local connector/wiring fault between module and network
  • Network-level fault (short, open, missing termination) affecting messages
  • Software/configuration problem after replacement or update

Fault status

⚠️ Status
No response to Network Management (NM) message on CCP bus — target control module did not reply to expected keepalive/wake message.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

U0100 U0073 U0121 B2799 B2800 B2810
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

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