By iCarsoft Official Store Technical Team, Automotive Diagnostics Editors · Updated October 13, 2026 · OEM technical references checked
Quick Answer
U0112 describes lost communication with battery energy control module b in the documented application. It does not prove a failed high-voltage battery, BECM B, charger or cell assembly. Save the original scan, confirm VIN scope and use approved multi-module network tests before choosing a repair.
1What Does the U0112 Code Mean?
For the documented application, U0112 concerns lost communication with battery energy control module b. Confirm the vehicle, reporting module and full wording before using this guide. The full fault record determines the test branch.
U0112 concerns an expected message from Battery Energy Control Module B. Identify the controller that reported the loss before deciding which side of the connection to test. A receiver can store this fault even when the battery controller has no record of an internal failure. The letter B identifies the manufacturer's controller assignment; it does not identify a battery bank, cell group or connector by itself.
Separate access to the battery controller from access to the rest of the vehicle. If the gateway and other controllers respond but BECM B does not, use the diagram to investigate that node's low-voltage feed, ground, wake path and communication branch. If several controllers are missing, investigate their shared prerequisites before narrowing the diagnosis to BECM B. These are branches to verify, not automatic conclusions.
Keep battery health and network availability as separate questions. Cell readings, charging status and isolation information may be unavailable because their source is offline. An empty display is not a measured bad battery. Conversely, a legitimate safety or service state can affect availability. Only qualified personnel should establish the applicable high-voltage state; do not bypass isolation to make a module appear online.
Restore communication before interpreting unsupported or stale battery data.
For a useful handoff, keep the original battery-controller identity beside every captured value. State whether the value came directly from the controller or from a receiving module's display, and whether it was available during the fault. Do not present an old or missing value as a new measurement. A shop investigating an intermittent loss needs the warning text, charging or propulsion state and module-response list from that event.
A later scan can confirm that access has returned, but it cannot reconstruct the original outage. Ask the technician to separate restored message delivery from the battery safety and performance checks still required.
The B suffix matters: do not silently merge BECM B with another battery-energy controller.
The Jaguar Land Rover submission in NHTSA investigation PE24-002 lists U0112 as lost communication with Battery Energy Control Module B. An Audi Q5/SQ5 diagnostic reference separately lists CAN: BECM with a no-message criterion. These application records support terminology; they do not establish a universal battery-health or battery-replacement test.
Keep the high-voltage battery condition separate from the message-delivery investigation. The B designation comes from the documented controller assignment, not from a measured cell or capacity result. Establish the prescribed safety and service state before testing. A supported scan may show where information is missing, but it cannot replace approved low-voltage measurements or the manufacturer’s high-voltage inspection procedure.
Qualified personnel must decide which safety and battery tests apply after the communication branch is repaired.
Save the full module wording and suffix before clearing; they can change the test path.
Separate U0112 from adjacent fault families
| Code | General description | Key distinction |
|---|---|---|
| U0112 | Lost Communication with Battery Energy Control Module B | This guide’s documented application; retain the full suffix. |
| U0121 | Lost Communication with ABS/Brake Control Module | A different module path; compare the reporting controller and vehicle function. |
| U0140 | Lost Communication with Body Control Module | A body-network code is not interchangeable with this module-specific result. |
Record the complete U0112 description. The suffix, reporting module and companion faults can change the diagnostic path. Use the manufacturer's full wording and test procedure for the exact vehicle.
2U0112 Symptoms and Likely Causes
Record U0112 symptoms and fault status; symptoms alone cannot identify a failed part.
Check whether companion faults share a proven cause.
Record the exact warning, when it appeared and which function changed; it is evidence, not proof of a failed module.
Compare saved multi-module reports with supported live data; unavailable data does not identify the cause.
Preserve the service history and inspect the disturbed branch first, while treating timing as a clue.
Save every module’s codes and status; a shared supply or network code can change the diagnostic order.
Practical cause-checking order
- Power, ground, connector or wake-state problem affecting the communication path: Low-voltage supply, ground or wake-state loss
- Open, shorted, corroded, chafed or water-damaged network wiring: CAN wiring, connector, termination or gateway interruption
- Gateway, termination, configuration or software condition: Configuration or software mismatch after module work
- Module intentionally asleep, isolated or unavailable during service: Service or isolation state blocking expected messages
- Internal controller fault only after external branches pass: Controller fault after external communication checks
Did U0112 appear after recent battery, module, harness, gateway or programming work? Recheck the documented connections, parts and setup steps affected by that work. Record battery and software history; a post-repair code does not prove the new part is defective.
3How Serious Is U0112, and Can You Drive?
Follow the owner manual and all battery, charging or propulsion warnings. A BECM B timeout does not establish a safe remaining driving distance. Stop safely and arrange qualified help for abnormal propulsion, charging behavior or a high-voltage safety warning; do not use a successful scan as permission to bypass the warning.
Record warning messages, operating conditions and service history. Do not induce wheel slip, emergency braking or a handling event on public roads. A red stop warning or abnormal control overrides any verification plan.
Stop and arrange a tow if steering, braking, propulsion, charging, parking-brake or other safety behavior is abnormal.
High-voltage battery access requires the specified isolation procedure and qualified personnel. Do not open the pack, bypass interlocks or infer electrical safety from a communication result.
4How to Diagnose U0112 in the Right Order
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Identify the application and preserve evidence
Save BECM B’s reporting module, current/history status, freeze frame, gateway list, charging warnings and every companion U-code before clearing.
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Inspect the relevant physical and electrical path
Use the VIN wiring diagram to identify BECM B, its receiver, low-voltage feeds, grounds, wake circuit and CAN segment; confirm whether another battery controller is fitted.
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Confirm architecture and prerequisites
With the high-voltage system in the prescribed safe state, inspect accessible low-voltage connectors, terminal retention, grounds and gateway links; do not open the pack.
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Separate network behavior from system behavior
Compare BECM B visibility from several modules and prove the approved CAN path and supply under the specified test state; a scan-tool timeout is not a battery measurement.
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Prove the repair path before parts
Separate intentional HV isolation, a dead 12V wake path, gateway filtering, configuration mismatch and a controller fault using the module report and service history.
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Verify the original condition after repair
Repair the demonstrated branch, complete required configuration or release steps, reread BECM B and verify charging/propulsion readiness through the OEM procedure.
Specifications are vehicle-specific. Use the exact VIN specifications, approved test points and required operating state. No generic value or drive cycle can replace the applicable procedure. Manufacturer examples here do not establish specifications for other applications.
5U0112 Repairs and Cost Planning
A U0112 repair must address the demonstrated failure. Do not replace an assembly from the code alone.
Recheck installation and required setup after repair. A no-message result is not a battery-health measurement; keep BECM communication, capacity and isolation tests separate.
Ask the shop to name the failed branch and the measurement supporting each proposed repair.
Authorize diagnosis before parts while the cause remains uncertain.
| Possible path | Quote basis |
|---|---|
| Repair the demonstrated power, ground, connector, harness, gateway or network branch | VIN-specific quote |
| Restore configuration, software or required setup only through the VIN-specific procedure | VIN-specific quote |
| Replace the isolated controller or assembly only after external evidence and the OEM test support that path | VIN-specific quote |
These are alternative repair paths, not prices to add together. Request a VIN-specific quote separating diagnosis, parts, labor, fluids, taxes, required setup and verification. Ask which failed test supports the proposed repair and whether warranty coverage applies.
6Using iCarsoft CR Eagle P for U0112
On a supported vehicle, iCarsoft CR Eagle P can save accessible faults, available freeze frame, live data and diagnostic reports. Preserve the U0112 evidence before clearing.
Compare the saved and final module records. Scan data supports diagnosis but does not replace the OEM reference, physical measurement or safety-system functional check.
Preserve the BECM B low-voltage supply, wake-up, gateway and CAN communication path evidence
iCarsoft CR Eagle P
Review supported codes and relevant live data together. Confirm the exact VIN, controller access, PIDs and any requested active test with iCarsoft before purchase; generic product capabilities do not guarantee a U0112-specific function.
Check current CR Eagle P price and availabilityCheck CR Eagle P compatibility by VINThe official product page describes supported full-system diagnostics, available live data, freeze frame and diagnostic reports; exact controller coverage and active tests depend on the VIN and software. Confirm the requested function by VIN before purchase. Follow OEM prerequisites and stop for abnormal operation.
Know the measurement boundary. Scan data describes ECU-provided information; it does not directly prove the physical condition of the BECM B low-voltage supply, wake-up, gateway and CAN communication path. Where required, use approved multi-module scan access, wiring diagram, voltage-drop/continuity tools and the VIN-specific network procedure and compare reported values with the relevant measured evidence.
7Verify the U0112 Repair
After repair, verify installation, clearance and required setup. Save the final findings and clear only erasable records as instructed. Battery disconnection is not a repair.
Run the manufacturer's applicable verification conditions in a safe workshop or route. Compare the original operating state with current data for the BECM B low-voltage supply, wake-up, gateway and CAN communication path, and check current and pending faults in related modules. A clean start or idle period does not prove the repair; use the OEM functional check for the affected system.
Compare the original and final fault status. Record the functional-check result and whether the original event returned.
If U0112 returns, compare its suffix, status, failure order and operating conditions with the saved baseline before replacing another part. Revisit the failed branch and inspect anything disturbed. Confirm the prescribed affected-system functional verification separately from code clearing.
Verification follows the system involved. After saving the original evidence, use the OEM procedure to clear erasable records, complete any required calibration or functional check, and compare the final module status with the original warning and fault conditions.
8Related BECM B Low-Voltage Supply, Wake-Up, Gateway And CAN Communication Path Code Guides
Compare the related monitor families below. Shared symptoms or components do not make their repair procedures interchangeable.
9U0112 Frequently Asked Questions
Does U0112 prove the named module is bad?
No. U0112 describes lost communication with battery energy control module b, not a confirmed part. Use the manufacturer’s network and module tests to distinguish power, wiring, gateway, software and controller branches before replacing parts.
What should I check first for U0112?
Save every module's codes and freeze frame before clearing. Confirm the full definition, suffix and VIN architecture. Then inspect recent battery, module, harness, gateway or programming work, connectors and shared supplies. Those facts determine whether the next test needs approved multi-module scan access, wiring diagram, voltage-drop/continuity tools and the VIN-specific network procedure or a manufacturer-specific functional procedure.
Can I drive with the U0112 code?
Follow the owner manual and all battery, charging or propulsion warnings. A BECM B timeout does not establish a safe remaining driving distance. Stop safely and arrange qualified help for abnormal propulsion, charging behavior or a high-voltage safety warning; do not use a successful scan as permission to bypass the warning.
Why did U0112 return after a part was replaced?
A clear command cannot establish HV safety, charging capability or cell condition.
What should a U0112 repair estimate include?
Ask for the failed-test evidence and a VIN-specific breakdown of diagnosis, parts, labor, taxes, required setup and verification. A code alone cannot establish the repair price.
Can CR Eagle P diagnose and clear U0112?
On a supported vehicle, CR Eagle P can organize available faults, freeze frame, live data and reports, and can clear erasable records after repair. Confirm exact ECU coverage. It cannot replace the OEM functional procedure or physical measurements for the BECM B low-voltage supply, wake-up, gateway and CAN communication path.
The iCarsoft Official Store Technical Team maintains the store's fault-code library. This guide organizes published technical references and verified product information; it does not document a hands-on test of a particular vehicle or claim an individual engineer's review.
Technical and cost references
- NHTSA investigation — BECM B communication evidence. DTC terminology only; not battery capacity, isolation or universal repair criteria.
- Audi 2013 Q5/SQ5 Quick Reference Specification Book, OBD table, printed p.172. Application-specific CAN: BECM no-message terminology; not universal battery-health criteria.
Product information: Official iCarsoft CR Eagle P page.
Editorial note: General diagnostic education, not a substitute for the owner's manual, current VIN-specific service information or professional inspection. Test limits, procedures, coverage and costs vary. Related articles provide context; apply only the specifications and repair procedures that match the vehicle. No universal failure rate, repair price or outcome is implied.
