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Home / DTC / B2809 — No Response NM Message (RRC)

B2809 — No Response NM Message (RRC)

Detailed page for trouble code B2809.

34,405codes
59brands
11,914generic
22,491specific
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Code

B2809

HYUNDAI B — Body

No Response NM Message (RRC)

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

Causes

  • Faulty RRC (rear-right) module
  • Broken, corroded or loose connector at RRC
  • Open or short in the CAN/NM wiring (CAN High, CAN Low, or power/ground)
  • Blown fuse or failed power/ground supply to RRC
  • Other module on same bus pulling down communications
  • Intermittent wiring damage (pinch, water intrusion)

Symptoms

  • Malfunction or loss of the specific rear-right functions controlled by RRC (e.g., door lock/window/mirror/lighting)
  • One or more communication-related DTCs present (communication timeouts)
  • Malfunction Indicator Lamp or warning messages related to body electronics
  • Intermittent or permanent loss of control for components at the rear right corner

What to check

  • Obtain full DTC report with a capable scan tool; note other network codes present
  • Confirm vehicle application and identify the RRC module location using service manual/wiring diagrams
  • Visually inspect RRC connector and harness for corrosion, bent pins, damage or water intrusion
  • Check fuses/relays powering the RRC module
  • With ignition ON, verify module presence on scan tool (can it be queried?)
  • Measure battery voltage at RRC power pin (should be ~11–14.5 V with ignition ON)

Signal parameters

  • Module supply voltage: ~11–14.5 V with ignition ON
  • Ground:
  • CAN bus idle (recessive): CANH ≈ 2.5 V, CANL ≈ 2.5 V (differential ≈ 0 V)
  • CAN bus dominant: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ≈ 2 V)
  • CAN bus termination: nominal ≈ 120 Ω across CANH–CANL (measured with power off)
  • No response/time-out from module when polled by scan tool

Diagnostic algorithm

  1. Connect professional scan tool; read and record all DTCs and freeze frame data. Note ignition cycle state when code set.
  2. Attempt to communicate with RRC via scan tool. If module communicates intermittently, suspect wiring/connector issues.
  3. Visually inspect RRC connector and harness; repair any corrosion, bent pins or damaged insulation. Reseal or replace connector if water intrusion found.
  4. Check related fuses and power feeds; verify battery voltage at the module power pin with ignition ON.
  5. Check ground continuity from RRC ground to chassis/negative battery. Secure or repair ground as necessary.
  6. Measure CANH/CANL voltages at the RRC connector with ignition ON. Compare idle and dominant voltages to expected values in signal_params.
  7. If CAN lines show abnormal voltages or bus off, isolate by disconnecting the RRC connector and re-measuring bus at an upstream point to find shorted/loaded segment.
  8. If wiring checks normal and power/ground/CAN are correct but module still does not respond, try software wake or reprogramming per service instructions (check for Technical Service Bulletins).
  9. If module cannot be woken or reprogrammed and wiring is verified good, replace the RRC module and reprogram/configure as required. Clear codes and road-test to confirm.
  10. After repairs, clear DTCs, perform full system communication check and verify normal operation of rear-right functions. Monitor for recurrence.

Likely causes

  • No battery power or ground at RRC
  • Damaged or disconnected CAN bus wiring to RRC
  • Faulty RRC module
  • Intermittent connector corrosion or water ingress

Fault status

⚠️ Status
No response to Network Management message from RRC module — communication timeout/absence.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

U0100 U0073 U0121 B2800 B2799 U0101
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

B2809

LAND ROVER B — Body

Pressure sensor power supply - short circuit to ground

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

Causes

  • Faulty RRC (rear-right) module
  • Broken, corroded or loose connector at RRC
  • Open or short in the CAN/NM wiring (CAN High, CAN Low, or power/ground)
  • Blown fuse or failed power/ground supply to RRC
  • Other module on same bus pulling down communications
  • Intermittent wiring damage (pinch, water intrusion)

Symptoms

  • Malfunction or loss of the specific rear-right functions controlled by RRC (e.g., door lock/window/mirror/lighting)
  • One or more communication-related DTCs present (communication timeouts)
  • Malfunction Indicator Lamp or warning messages related to body electronics
  • Intermittent or permanent loss of control for components at the rear right corner

What to check

  • Obtain full DTC report with a capable scan tool; note other network codes present
  • Confirm vehicle application and identify the RRC module location using service manual/wiring diagrams
  • Visually inspect RRC connector and harness for corrosion, bent pins, damage or water intrusion
  • Check fuses/relays powering the RRC module
  • With ignition ON, verify module presence on scan tool (can it be queried?)
  • Measure battery voltage at RRC power pin (should be ~11–14.5 V with ignition ON)

Signal parameters

  • Module supply voltage: ~11–14.5 V with ignition ON
  • Ground:
  • CAN bus idle (recessive): CANH ≈ 2.5 V, CANL ≈ 2.5 V (differential ≈ 0 V)
  • CAN bus dominant: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ≈ 2 V)
  • CAN bus termination: nominal ≈ 120 Ω across CANH–CANL (measured with power off)
  • No response/time-out from module when polled by scan tool

Diagnostic algorithm

  1. Connect professional scan tool; read and record all DTCs and freeze frame data. Note ignition cycle state when code set.
  2. Attempt to communicate with RRC via scan tool. If module communicates intermittently, suspect wiring/connector issues.
  3. Visually inspect RRC connector and harness; repair any corrosion, bent pins or damaged insulation. Reseal or replace connector if water intrusion found.
  4. Check related fuses and power feeds; verify battery voltage at the module power pin with ignition ON.
  5. Check ground continuity from RRC ground to chassis/negative battery. Secure or repair ground as necessary.
  6. Measure CANH/CANL voltages at the RRC connector with ignition ON. Compare idle and dominant voltages to expected values in signal_params.
  7. If CAN lines show abnormal voltages or bus off, isolate by disconnecting the RRC connector and re-measuring bus at an upstream point to find shorted/loaded segment.
  8. If wiring checks normal and power/ground/CAN are correct but module still does not respond, try software wake or reprogramming per service instructions (check for Technical Service Bulletins).
  9. If module cannot be woken or reprogrammed and wiring is verified good, replace the RRC module and reprogram/configure as required. Clear codes and road-test to confirm.
  10. After repairs, clear DTCs, perform full system communication check and verify normal operation of rear-right functions. Monitor for recurrence.

Likely causes

  • No battery power or ground at RRC
  • Damaged or disconnected CAN bus wiring to RRC
  • Faulty RRC module
  • Intermittent connector corrosion or water ingress

Fault status

⚠️ Status
No response to Network Management message from RRC module — communication timeout/absence.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

U0100 U0073 U0121 B2800 B2799 U0101
270

Browse 270 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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