B2A01

Code

Generic B — Body

Door Lock Actuator Circuit Low Voltage

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 28 RU: 9

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Page language: EN

Causes

Weak or discharged vehicle battery
Corroded, loose, or damaged connector at the door lock actuator
Broken or chafed wiring causing high resistance or a partial short to ground
Poor chassis or module ground connection
Blown fuse or faulty relay in the door lock power feed
Failing door lock actuator motor drawing excessive current

Symptoms

Door lock(s) inoperative on affected door(s)
Lock moves slowly or intermittently
Audible clicking from actuator but no full lock movement
Fuses related to door locks blow repeatedly
Multiple door lock DTCs or inconsistent lock/unlock behavior from key fob
DTC stored in BCM and possibly a corresponding warning message on the dash

What to check

Pull DTCs and note freeze-frame data and which door(s) are reported
Visually inspect wiring, connectors and actuator for corrosion, damage or water ingress
Check fuses and relays for the door lock circuit
Measure battery voltage (key off and with engine running) and ensure good battery terminals and charging system
With a scan tool, command the lock/unlock and observe BCM output status
Measure voltage at the actuator connector while commanding lock/unlock (connector pinned to the actuator)

Signal parameters

Typical battery/rest voltage: ~12.4–12.8 V (engine off); charging system ~13.5–14.8 V (engine running)
Expected voltage at actuator while commanded: close to battery voltage; generally should not drop below ~9–10 V under load (vehicle-specific)
Typical actuator current draw (varies by design): commonly 0.5–6 A during movement; stall current may be higher — check OEM spec if available
Circuit continuity: low resistance between actuator supply and fuse/relay (
If a PWM or pulsed drive is used, observe duty cycle and frequency with an oscilloscope or scan data (see OEM values)

Diagnostic algorithm

Retrieve and record all stored codes and freeze-frame data. Verify B2A01 and note which door(s) are affected.
Visually inspect the door lock actuator, connector, harness, door jamb grommet and ground points for damage, corrosion or water ingress. Repair visible issues.
Verify battery and charging system: check battery voltage at rest and during actuator command. Recharge/replace battery or clean terminals if low or corroded.
Check fuses/relays for the door lock circuit; replace if blown and continue diagnosis if it re-blows.
With the door unlocked and actuator connector accessible, command lock/unlock with a scan tool while measuring voltage at the actuator supply terminal. Note voltage drop when commanded.
Measure ground potential at the actuator while commanding. If ground is poor, trace and repair ground connection(s) to chassis and BCM.
Measure actuator current draw during operation. Compare to typical range; excessive current suggests a binding or failing actuator (replace actuator to confirm).
If voltage at the connector is low but battery voltage is good, isolate the harness by disconnecting the actuator and measure voltage at the harness pin while commanding — if voltage is present at the harness, the actuator is likely faulty; if not, continue upstream (fuse, relay, splice, wiring)
Perform wiggle/strain tests along harness while commanding to detect intermittent opens/shorts. Use back-probing and/or a noid light when appropriate.
If wiring and actuator check OK, inspect BCM output and grounds. Verify module software level and vehicle-specific service information for known issues or TSBs.
After repairs or component replacements, clear codes and cycle the locks several times. Re-scan after a test drive to ensure code does not return.
Safety note: when applying direct battery voltage for bench testing, take precautions to avoid short circuits and avoid exceeding manufacturer test procedures.

Likely causes

Corroded/loose connector or ground at the affected door (common)
High resistance in supply or ground wiring (worn/chafed harness)
Weak vehicle battery or poor main battery connections
Failing actuator motor (stuck or internal short)

Fault status

⚠️ Status

B2A01 — Door Lock Actuator Circuit Low Voltage: BCM detected low voltage or excessive voltage drop on door lock actuator circuit. May cause intermittent or failed lock operation.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours