Code
U0111
Generic
U — Network/User
Lost Communication With Battery Energy Control Module A
Views:
UK: 16
EN: 28
RU: 50
AI status
Completed
Completed
100%
Causes
- Open or short in CAN/data bus wiring between BECM and other modules
- Poor or intermittent BECM power or ground (fuse, relay, connector, battery voltage)
- Corroded, loose or damaged connector at the BECM
- Failed BECM (internal electronics)
- Faulty module on the same data bus pulling the bus down
- Incorrect or missing module software/calibration (after service update)
Symptoms
- MIL/Warning indicator illuminated (HV/Battery/Service warnings)
- HV battery management features disabled (charging, regen, charge control limited)
- Reduced vehicle performance or limp mode
- Battery or HV system warnings/messages in instrument cluster
- Inability to read BECM parameters with a scan tool (no response)
- Other modules reporting related U-codes (indicating network issues)
What to check
- Connect a scan tool and record freeze frame, pending and permanent codes; attempt to communicate with BECM A
- Check vehicle battery voltage (key on, engine off) — should be ~12–14V; verify good battery state
- Verify fuses and relays for BECM power circuits; check for presence of ignition and B+ at module power pins
- Visually inspect BECM connector and wiring for damage, corrosion, bent pins, or water intrusion
- Check for other U-codes that indicate wider CAN bus failure (U0073, U0100, U0141, etc.)
- Measure CAN bus continuity and resistance between CAN_H and CAN_L at multiple points; check for correct termination resistance (~60 ohm across H-L at two-term device, or ~120 ohm single)
Signal parameters
- Key on, engine off battery supply to BECM: ~11–14 V measured at module power pin
- Ground(s): near 0 V with low resistance to chassis ground
- CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (differential ≈ 0 V)
- CAN bus dominant: CAN_H ≈ 3.5–3.9 V, CAN_L ≈ 1.1–1.5 V (differential ≈ 2.0 V)
- Typical CAN bus baud rates: 500 kb/s or 250 kb/s depending on vehicle — verify with service data
- Bus termination: combined resistance measured across CAN_H and CAN_L (system dependent) typically ~60 ohm (two 120 ohm terminators in parallel)
Diagnostic algorithm
- Read and record all DTCs and freeze frame data with a capable scan tool. Note if BECM is present/listed in module list.
- Attempt communication specifically with BECM A. Confirm “no response” status and note any related network errors.
- Verify vehicle battery voltage and state. If low, charge or raise to proper voltage before continuing.
- Inspect and test fuses and relays that supply BECM power. Verify B+ and switched ignition power at the BECM power pins with key ON.
- Inspect BECM connector: disengage, inspect pins for corrosion, damage, or pushed-out pins. Clean and reseat if necessary.
- With the scan tool monitoring the CAN bus, check for other modules responding. If no modules respond, suspect bus power/termination. If some respond and BECM does not, focus on wiring/connectors to BECM.
- Measure DC voltages at CAN_H and CAN_L at the BECM connector with key ON. Compare to expected idle values (~2.5 V) and check differential.
- Measure resistance/continuity of CAN_H and CAN_L back to a known-good module on the same bus. Check for short to battery or ground and for opens.
- If intermittent, perform wiggle testing on harness and connectors while monitoring bus traffic or using an oscilloscope to detect noise or signal loss.
- If wiring and power/ground are good, try to reflash or update BECM software per manufacturer procedure (some faults cleared by reprogramming).
- If failure persists and all wiring/power/ground/sw update checks are OK, consider replacing BECM A. After replacement or repair, clear codes and verify proper communication and vehicle function on road test.
- Document findings; if replacing modules, follow immobilizer or configuration pairing procedures as required by manufacturer.
Likely causes
- Blown fuse or faulty BECM power/ignition relay preventing module turn-on
- Damaged or corroded connector at the BECM causing intermittent contact
- Short to ground or short to battery on CAN_H or CAN_L wiring
- Failed BECM hardware (most likely if power/ground and bus wiring check OK)
- Another module pulling CAN bus low/high or causing bus errors
Fault status
Status
Lost Communication With Battery Energy Control Module A — no response from BECM A on the vehicle data bus (CAN).
Repair difficulty: Medium
Diagnostic time: 1.0-4.0 hours
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Code
U0111
HYUNDAI
U — Network/User
Lost Communication With Battery Energy Control Module “A” | Lost Communication With Battery Energy Control Module “A” (C-CAN)
Views:
UK: 9
EN: 14
RU: 36
AI status
Completed
Completed
100%
Causes
- Open or short in CAN/data bus wiring between BECM and other modules
- Poor or intermittent BECM power or ground (fuse, relay, connector, battery voltage)
- Corroded, loose or damaged connector at the BECM
- Failed BECM (internal electronics)
- Faulty module on the same data bus pulling the bus down
- Incorrect or missing module software/calibration (after service update)
Symptoms
- MIL/Warning indicator illuminated (HV/Battery/Service warnings)
- HV battery management features disabled (charging, regen, charge control limited)
- Reduced vehicle performance or limp mode
- Battery or HV system warnings/messages in instrument cluster
- Inability to read BECM parameters with a scan tool (no response)
- Other modules reporting related U-codes (indicating network issues)
What to check
- Connect a scan tool and record freeze frame, pending and permanent codes; attempt to communicate with BECM A
- Check vehicle battery voltage (key on, engine off) — should be ~12–14V; verify good battery state
- Verify fuses and relays for BECM power circuits; check for presence of ignition and B+ at module power pins
- Visually inspect BECM connector and wiring for damage, corrosion, bent pins, or water intrusion
- Check for other U-codes that indicate wider CAN bus failure (U0073, U0100, U0141, etc.)
- Measure CAN bus continuity and resistance between CAN_H and CAN_L at multiple points; check for correct termination resistance (~60 ohm across H-L at two-term device, or ~120 ohm single)
Signal parameters
- Key on, engine off battery supply to BECM: ~11–14 V measured at module power pin
- Ground(s): near 0 V with low resistance to chassis ground
- CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (differential ≈ 0 V)
- CAN bus dominant: CAN_H ≈ 3.5–3.9 V, CAN_L ≈ 1.1–1.5 V (differential ≈ 2.0 V)
- Typical CAN bus baud rates: 500 kb/s or 250 kb/s depending on vehicle — verify with service data
- Bus termination: combined resistance measured across CAN_H and CAN_L (system dependent) typically ~60 ohm (two 120 ohm terminators in parallel)
Diagnostic algorithm
- Read and record all DTCs and freeze frame data with a capable scan tool. Note if BECM is present/listed in module list.
- Attempt communication specifically with BECM A. Confirm “no response” status and note any related network errors.
- Verify vehicle battery voltage and state. If low, charge or raise to proper voltage before continuing.
- Inspect and test fuses and relays that supply BECM power. Verify B+ and switched ignition power at the BECM power pins with key ON.
- Inspect BECM connector: disengage, inspect pins for corrosion, damage, or pushed-out pins. Clean and reseat if necessary.
- With the scan tool monitoring the CAN bus, check for other modules responding. If no modules respond, suspect bus power/termination. If some respond and BECM does not, focus on wiring/connectors to BECM.
- Measure DC voltages at CAN_H and CAN_L at the BECM connector with key ON. Compare to expected idle values (~2.5 V) and check differential.
- Measure resistance/continuity of CAN_H and CAN_L back to a known-good module on the same bus. Check for short to battery or ground and for opens.
- If intermittent, perform wiggle testing on harness and connectors while monitoring bus traffic or using an oscilloscope to detect noise or signal loss.
- If wiring and power/ground are good, try to reflash or update BECM software per manufacturer procedure (some faults cleared by reprogramming).
- If failure persists and all wiring/power/ground/sw update checks are OK, consider replacing BECM A. After replacement or repair, clear codes and verify proper communication and vehicle function on road test.
- Document findings; if replacing modules, follow immobilizer or configuration pairing procedures as required by manufacturer.
Likely causes
- Blown fuse or faulty BECM power/ignition relay preventing module turn-on
- Damaged or corroded connector at the BECM causing intermittent contact
- Short to ground or short to battery on CAN_H or CAN_L wiring
- Failed BECM hardware (most likely if power/ground and bus wiring check OK)
- Another module pulling CAN bus low/high or causing bus errors
Fault status
Status
Lost Communication With Battery Energy Control Module A — no response from BECM A on the vehicle data bus (CAN).
Repair difficulty: Medium
Diagnostic time: 1.0-4.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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Code
U0111
LAND ROVER
U — Network/User
Lost communication with battery power control module A
Views:
UK: 3
EN: 24
RU: 42
AI status
Completed
Completed
100%
Causes
- Open or short in CAN/data bus wiring between BECM and other modules
- Poor or intermittent BECM power or ground (fuse, relay, connector, battery voltage)
- Corroded, loose or damaged connector at the BECM
- Failed BECM (internal electronics)
- Faulty module on the same data bus pulling the bus down
- Incorrect or missing module software/calibration (after service update)
Symptoms
- MIL/Warning indicator illuminated (HV/Battery/Service warnings)
- HV battery management features disabled (charging, regen, charge control limited)
- Reduced vehicle performance or limp mode
- Battery or HV system warnings/messages in instrument cluster
- Inability to read BECM parameters with a scan tool (no response)
- Other modules reporting related U-codes (indicating network issues)
What to check
- Connect a scan tool and record freeze frame, pending and permanent codes; attempt to communicate with BECM A
- Check vehicle battery voltage (key on, engine off) — should be ~12–14V; verify good battery state
- Verify fuses and relays for BECM power circuits; check for presence of ignition and B+ at module power pins
- Visually inspect BECM connector and wiring for damage, corrosion, bent pins, or water intrusion
- Check for other U-codes that indicate wider CAN bus failure (U0073, U0100, U0141, etc.)
- Measure CAN bus continuity and resistance between CAN_H and CAN_L at multiple points; check for correct termination resistance (~60 ohm across H-L at two-term device, or ~120 ohm single)
Signal parameters
- Key on, engine off battery supply to BECM: ~11–14 V measured at module power pin
- Ground(s): near 0 V with low resistance to chassis ground
- CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (differential ≈ 0 V)
- CAN bus dominant: CAN_H ≈ 3.5–3.9 V, CAN_L ≈ 1.1–1.5 V (differential ≈ 2.0 V)
- Typical CAN bus baud rates: 500 kb/s or 250 kb/s depending on vehicle — verify with service data
- Bus termination: combined resistance measured across CAN_H and CAN_L (system dependent) typically ~60 ohm (two 120 ohm terminators in parallel)
Diagnostic algorithm
- Read and record all DTCs and freeze frame data with a capable scan tool. Note if BECM is present/listed in module list.
- Attempt communication specifically with BECM A. Confirm “no response” status and note any related network errors.
- Verify vehicle battery voltage and state. If low, charge or raise to proper voltage before continuing.
- Inspect and test fuses and relays that supply BECM power. Verify B+ and switched ignition power at the BECM power pins with key ON.
- Inspect BECM connector: disengage, inspect pins for corrosion, damage, or pushed-out pins. Clean and reseat if necessary.
- With the scan tool monitoring the CAN bus, check for other modules responding. If no modules respond, suspect bus power/termination. If some respond and BECM does not, focus on wiring/connectors to BECM.
- Measure DC voltages at CAN_H and CAN_L at the BECM connector with key ON. Compare to expected idle values (~2.5 V) and check differential.
- Measure resistance/continuity of CAN_H and CAN_L back to a known-good module on the same bus. Check for short to battery or ground and for opens.
- If intermittent, perform wiggle testing on harness and connectors while monitoring bus traffic or using an oscilloscope to detect noise or signal loss.
- If wiring and power/ground are good, try to reflash or update BECM software per manufacturer procedure (some faults cleared by reprogramming).
- If failure persists and all wiring/power/ground/sw update checks are OK, consider replacing BECM A. After replacement or repair, clear codes and verify proper communication and vehicle function on road test.
- Document findings; if replacing modules, follow immobilizer or configuration pairing procedures as required by manufacturer.
Likely causes
- Blown fuse or faulty BECM power/ignition relay preventing module turn-on
- Damaged or corroded connector at the BECM causing intermittent contact
- Short to ground or short to battery on CAN_H or CAN_L wiring
- Failed BECM hardware (most likely if power/ground and bus wiring check OK)
- Another module pulling CAN bus low/high or causing bus errors
Fault status
Status
Lost Communication With Battery Energy Control Module A — no response from BECM A on the vehicle data bus (CAN).
Repair difficulty: Medium
Diagnostic time: 1.0-4.0 hours
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Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 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
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0
Send to email