Diagnostic trouble code

U1A4B

U1A4B Fault Code

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Car Codes diagnostic trouble code

U1A4BDiagnostic priority

…if the right-side BSM module is replaced alone: BSM aiming fails BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54 stored in memory (CX-3, MX-5 only) NOTE: Since a new BSM control module does not retain the vehicle specification information, it is necessary to acquire and store the vehicle specification information transmitted via CAN communication from the combination…

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Code interpretation

What U1A4B means

This code indicates Vehicle fault code with verified manufacturer evidence Its precise meaning depends on the reporting control module, complete failure-type suffix, model year, powertrain and software level.

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Driver experience

Symptoms you may notice

A stored diagnostic trouble code or a related system warning.

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Test, do not guess

Possible causes

The precise cause depends on the reporting module, vehicle specification, circuit condition and software level.

Evidence-led checks

Recommended diagnostic route

Save the complete scan and confirm the code against model-specific technical information before testing.

Capture the evidenceSave the complete all-module scan, code suffixes and freeze-frame data.
Prove the basicsTest battery condition, system voltage, power and grounds.
Identify the reporterConfirm the module that logged the code and check circuit integrity.
Compare live dataReview commanded and actual values under the conditions that set the code.
Test before replacingUse model-specific wiring diagrams, pin tests and technical information.
Verify the repairClear the code only after recording evidence, then confirm it does not return.

Vehicle fitment

Vehicle applicability

Mazda MX-5, Mazda CX-30

Before clearing

Can the code be cleared?

Clearing a code without fixing the cause removes useful evidence and may only switch the warning off temporarily. Save the full scan first; a permanent or repeatedly returning code needs testing.

A DTC is evidence, not a parts order.

Confirm the suffix, reporting module, model, year, engine and live data before replacing a component.

Verified public evidence

Manufacturer and model coverage

39 public manufacturer records match this search. These records support applicability research but do not replace VIN-specific workshop information.

U1A4BLand Rover Discovery
DISCOVERY · 2017 · Multiple/unspecified

Issue: Land Rover has received reports where during diagnosis of the surround camera system the Diagnostic Trouble Code (DTC) B12BD-31 "Rear Camera - No Signal" and or U1A4B-49 "Control Module…

U1A4BLand Rover Range Rover
RANGE ROVER · 2013 · Multiple/unspecified

Issue: Land Rover has received reports where during diagnosis of the surround camera system the Diagnostic Trouble Code (DTC) B12BD-31 ?Rear Camera - No Signal? and or U1A4B-49 ?Control Module…

U1A4BLand Rover Range Rover
RANGE ROVER · 2013 · Multiple/unspecified

Issue: Land Rover has received reports where during diagnosis of the surround camera system the Diagnostic Trouble Code (DTC) B12BD-31 "Rear Camera - No Signal" and or U1A4B-49 "Control Module…

U1A4BMazda CX-30
CX-3 · 2016 · Multiple/unspecified

Some vehicles with Blind Spot Monitoring (BSM) may experience the following conditions (similar to when the BSM control modules detect dirt on the rear bumper surface): DTC U1A4B:97 - Radar…

U1A4BMazda CX-30
CX-3 · 2017 · Multiple/unspecified

Some vehicles with Blind Spot Monitoring (BSM) may experience the following conditions (similar to when the BSM control modules detect dirt on the rear bumper surface): DTC U1A4B:97 - Radar…

U1A4BMazda CX-30
CX-3 · 2016 · Multiple/unspecified

…right-side BSM module is replaced alone: BSM aiming fails, BSM OFF" indicator ON, Center Display warning message, BSM failsafe (No operation), DTC U3000:54 stored in memory, DTC U1A4B:54 stored in…

U1A4BMazda CX-30
CX-3 · 2016 · Multiple/unspecified

…if the right-side BSM module is replaced alone: BSM aiming fails BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54…

U1A4BMazda CX-30
CX-3 · 2017 · Multiple/unspecified

…if the right-side BSM module is replaced alone: BSM aiming fails BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54…

U1A4BMazda CX-30
CX-3 · 2018 · Multiple/unspecified

…if the right-side BSM module is replaced alone: BSM aiming fails BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54…

U1A4BMazda CX-30
CX-3 · 2019 · Multiple/unspecified

…if the right-side BSM module is replaced alone: BSM aiming fails BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54…

U1A4BMazda CX-30
CX-3 · 2020 · Multiple/unspecified

…if the right-side BSM module is replaced alone: BSM aiming fails BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54…

U1A4BMazda CX-30
CX-3 · 2021 · Multiple/unspecified

…if the right-side BSM module is replaced alone: BSM aiming fails BSM OFF" indicator ON Center Display warning message BSM failsafe (No operation) DTC U3000:54 stored in memory DTC U1A4B:54…

U1A4BMazda CX-30
CX-3 · 2016 · Multiple/unspecified

…SM module is replaced alone: * BSM aiming fails * "BSM OFF" indicator ON * Center Display warning message * BSM failsafe (No operation) * DTC U3000:54 stored in memory…

U1A4BMazda CX-30
CX-3 · 2017 · Multiple/unspecified

…SM module is replaced alone: * BSM aiming fails * "BSM OFF" indicator ON * Center Display warning message * BSM failsafe (No operation) * DTC U3000:54 stored in memory…

U1A4BMazda CX-30
CX-3 · 2018 · Multiple/unspecified

…SM module is replaced alone: * BSM aiming fails * "BSM OFF" indicator ON * Center Display warning message * BSM failsafe (No operation) * DTC U3000:54 stored in memory…

U1A4BMazda CX-30
CX-3 · 2019 · Multiple/unspecified

…SM module is replaced alone: * BSM aiming fails * "BSM OFF" indicator ON * Center Display warning message * BSM failsafe (No operation) * DTC U3000:54 stored in memory…

U1A4BMazda CX-30
CX-3 · 2020 · Multiple/unspecified

…SM module is replaced alone: * BSM aiming fails * "BSM OFF" indicator ON * Center Display warning message * BSM failsafe (No operation) * DTC U3000:54 stored in memory…

U1A4BMazda CX-30
CX-3 · 2021 · Multiple/unspecified

…SM module is replaced alone: * BSM aiming fails * "BSM OFF" indicator ON * Center Display warning message * BSM failsafe (No operation) * DTC U3000:54 stored in memory…

U1A4BMazda MX-5
MX-5 · 2016 · Multiple/unspecified

BSM OFF INDICATOR ON WITH DTC U1A4B:97 OR U3000:97. SOME VEHICLES WITH BLIND SPOT MONITORING (BSM) MAY EXPERIENCE THE FOLLOWING CONDITIONS (SIMILAR TO WHEN THE BSM CONTROL MODULES DETECT DIRT…

U1A4BMazda MX-5
MX-5 · 2016 · Multiple/unspecified

Some vehicles with Blind Spot Monitoring (BSM) may experience the following conditions (similar to when the BSM control modules detect dirt on the rear bumper surface): DTC U1A4B:97 - Radar…