Code
B2399
Generic
B — Body
Body Control Module - Undefined Subsystem Fault
Views:
UK: 0
EN: 0
RU: 0
AI status
Completed
Completed
100%
Causes
- BCM internal hardware or software fault
- Corrupt or outdated BCM software/calibration
- Low or unstable battery voltage or poor ground
- Faulty or intermittent wiring/connector to the BCM
- Loss of CAN/LIN network communications or bus errors
- Shorts or opens on sensor/actuator circuits the BCM monitors
Symptoms
- One or more body functions operating intermittently or not at all (locks, lamps, wipers, windows, etc.)
- Multiple unrelated body warning messages on cluster or info displays
- Fail to wake or go to sleep improperly; vehicle security/remote issues
- Interior lights, courtesy lamps, or exterior lighting may behave erratically
- Possible CAN network-related symptoms (other modules throwing communications codes)
What to check
- Read all stored DTCs and freeze frame data from BCM and gateway module; note time of occurrence and others codes
- Verify battery voltage (key off and key on) and check for parasitic drain if low
- Visually inspect BCM connector(s) and wiring for corrosion, bent pins, water intrusion, or damage
- Check BCM power and ground circuits for proper voltage and low resistance to chassis
- Scan CAN/LIN bus for active messages and bus errors with a capable scan tool or scope
- Inspect related fuses and relays for the body systems involved
Signal parameters
- VBATT (Key On): ~12.0–14.5 V (should be stable under load)
- Ground resistance:
- CAN_H idle: ~2.5 V (differential nominal when combined with CAN_L)
- CAN_L idle: ~2.5 V (see differential; CAN_H ~2.5V and CAN_L ~2.5V when idle, differential ~0V until driven — expect approx. 2.5V/1.5V depending on vehicle)
- CAN bus activity: regular message frames for BCM and adjacent modules when key on
- Wake/sleep messages and module awake state visible in scan tool parameters
Diagnostic algorithm
- Capture and record all current and historic DTCs from BCM and gateway; save freeze frame data and note recurrence conditions.
- Verify battery state-of-charge and charging system; correct any low-voltage issues before further tests.
- Clear codes and reproduce fault while monitoring live data to capture any patterns or related codes.
- Inspect BCM connectors, pins and harness for corrosion, water ingress, or damage; repair any physical faults found.
- With a multimeter/scope check BCM supply and ground pins for proper voltage and low impedance; wiggle harness to check for intermittent faults.
- Check CAN/LIN communication: verify bus termination, measure voltages, observe message traffic and error frames with a capable scan tool or oscilloscope.
- If communication or bus errors present, isolate segments or disconnect suspected devices one at a time to find the faulted node.
- Check related sensors/actuators for shorts, opens or excessive current draw that could trigger internal BCM fault detection.
- Consult manufacturer service information for code specifics, TSBs, and required data; apply published software updates or calibrations if available.
- If hardware fault confirmed after all checks, follow OEM procedure for BCM repair or replacement and ensure correct programming/configuration. Do not replace BCM without verifying external causes first.
Likely causes
- Poor battery/ground or supply to the BCM (most common)
- CAN bus communication error between BCM and other modules
- Corroded/loose BCM connector or damaged harness
- BCM firmware/configuration corruption requiring reflash
- Intermittent sensor/actuator loading a BCM input
Fault status
Status
BCM undefined subsystem fault logged. Intermittent or persistent body control malfunction; further electrical and communication diagnostics required.
Repair difficulty: Hard
Diagnostic time: 1.5-4.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
1
LAND ROVER 2
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualOfficial 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
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualWorkshop 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
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Code
B2399
LAND ROVER
B — Body
Head failure in the grounding circuit of the retention potentiometer
Views:
UK: 10
EN: 14
RU: 8
AI status
Completed
Completed
100%
Causes
- BCM internal hardware or software fault
- Corrupt or outdated BCM software/calibration
- Low or unstable battery voltage or poor ground
- Faulty or intermittent wiring/connector to the BCM
- Loss of CAN/LIN network communications or bus errors
- Shorts or opens on sensor/actuator circuits the BCM monitors
Symptoms
- One or more body functions operating intermittently or not at all (locks, lamps, wipers, windows, etc.)
- Multiple unrelated body warning messages on cluster or info displays
- Fail to wake or go to sleep improperly; vehicle security/remote issues
- Interior lights, courtesy lamps, or exterior lighting may behave erratically
- Possible CAN network-related symptoms (other modules throwing communications codes)
What to check
- Read all stored DTCs and freeze frame data from BCM and gateway module; note time of occurrence and others codes
- Verify battery voltage (key off and key on) and check for parasitic drain if low
- Visually inspect BCM connector(s) and wiring for corrosion, bent pins, water intrusion, or damage
- Check BCM power and ground circuits for proper voltage and low resistance to chassis
- Scan CAN/LIN bus for active messages and bus errors with a capable scan tool or scope
- Inspect related fuses and relays for the body systems involved
Signal parameters
- VBATT (Key On): ~12.0–14.5 V (should be stable under load)
- Ground resistance:
- CAN_H idle: ~2.5 V (differential nominal when combined with CAN_L)
- CAN_L idle: ~2.5 V (see differential; CAN_H ~2.5V and CAN_L ~2.5V when idle, differential ~0V until driven — expect approx. 2.5V/1.5V depending on vehicle)
- CAN bus activity: regular message frames for BCM and adjacent modules when key on
- Wake/sleep messages and module awake state visible in scan tool parameters
Diagnostic algorithm
- Capture and record all current and historic DTCs from BCM and gateway; save freeze frame data and note recurrence conditions.
- Verify battery state-of-charge and charging system; correct any low-voltage issues before further tests.
- Clear codes and reproduce fault while monitoring live data to capture any patterns or related codes.
- Inspect BCM connectors, pins and harness for corrosion, water ingress, or damage; repair any physical faults found.
- With a multimeter/scope check BCM supply and ground pins for proper voltage and low impedance; wiggle harness to check for intermittent faults.
- Check CAN/LIN communication: verify bus termination, measure voltages, observe message traffic and error frames with a capable scan tool or oscilloscope.
- If communication or bus errors present, isolate segments or disconnect suspected devices one at a time to find the faulted node.
- Check related sensors/actuators for shorts, opens or excessive current draw that could trigger internal BCM fault detection.
- Consult manufacturer service information for code specifics, TSBs, and required data; apply published software updates or calibrations if available.
- If hardware fault confirmed after all checks, follow OEM procedure for BCM repair or replacement and ensure correct programming/configuration. Do not replace BCM without verifying external causes first.
Likely causes
- Poor battery/ground or supply to the BCM (most common)
- CAN bus communication error between BCM and other modules
- Corroded/loose BCM connector or damaged harness
- BCM firmware/configuration corruption requiring reflash
- Intermittent sensor/actuator loading a BCM input
Fault status
Status
BCM undefined subsystem fault logged. Intermittent or persistent body control malfunction; further electrical and communication diagnostics required.
Repair difficulty: Hard
Diagnostic time: 1.5-4.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
2
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualOfficial 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
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualWorkshop 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
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