Code
B1276
LAND ROVER
B — Body
Foot servo motor potentiometer - circuit failure
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UK: 7
EN: 10
RU: 11
AI status
Completed
Completed
100%
Causes
- Open, short to ground or short to battery in potentiometer signal or reference wiring
- Damaged or corroded connector / poor pin contact at the foot servo
- Failed foot servo motor internal potentiometer (wear or contamination)
- Water ingress or debris in the actuator assembly
- HVAC control module / body control module fault or poor ground
Symptoms
- HVAC foot/vent flap fails to move or moves erratically
- Incorrect air distribution (no foot-level airflow or stuck flap)
- HVAC fault indicator or DTC present
- Unusual clicking from foot actuator or reduced actuator response
- Intermittent operation of vent mode or inability to change vent selection
What to check
- Read and record all HVAC-related DTCs and freeze frame data
- Visual inspection of foot servo connector and wiring for damage, corrosion, moisture
- Back-probe connector and measure reference voltage, signal voltage and ground
- Operate HVAC vent selection while observing potentiometer signal for smooth change
- Wiggle test harness while observing signal for intermittent changes
Signal parameters
- Reference voltage to potentiometer: typically ~5 V (verify with vehicle diagram)
- Potentiometer output voltage: should change smoothly over a defined range (~0.5–4.5 V) as actuator moves
- Expected continuity between pot terminals: check resistance per service data (varies by actuator)
- Open-circuit condition: infinite resistance between signal and reference/ground
- Short condition: signal stuck near 0 V (short to ground) or near battery/5 V (short to supply)
Diagnostic algorithm
- Retrieve DTCs with a factory-level scan tool and note any related codes (HVAC, grounds, other actuators).
- Perform a visual inspection: check the actuator connector, pins, and wiring for corrosion, damage, or moisture. Repair obvious issues.
- With ignition on (engine off or per service procedure), back-probe the servo connector. Verify reference voltage and ground presence at the connector.
- Command the foot flap/actuator through the HVAC controls while monitoring potentiometer signal voltage. Signal should change smoothly across its full travel. If signal is fixed, erratic, or out-of-range, suspect pot or wiring.
- Disconnect actuator and measure resistance across potentiometer terminals if accessible (compare to service values). Check for open/short.
- Wiggle the harness and connector while monitoring the signal for intermittent faults. Repair any pin movement or broken wires.
- If wiring and connector check good, bench-test or replace the foot servo actuator (potentiometer) and retest.
- If actuator and wiring are confirmed good, test or replace the HVAC control module or check module grounds per service manual.
- After repairs, clear codes and verify proper operation through full range of vent/flap positions and a road/test cycle as required.
Likely causes
- Wiring chafe causing intermittent short to ground on the pot signal
- Corroded connector pins at the foot servo harness connector
- Internal potentiometer tracks worn or contaminated inside the servo
- Connector not fully seated after previous service
- Moisture intrusion into the foot servo assembly
Fault status
Status
B1276 - Foot servo motor potentiometer circuit failure detected
Repair difficulty: Medium
Diagnostic time: 0.5 - 2.0 hours
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