Code
B1271
LAND ROVER
B — Body
Heating on the servo motor potentiometer - short circuit to ground
Views:
UK: 6
EN: 14
RU: 6
AI status
Completed
Completed
100%
Causes
- Short circuit from potentiometer signal or supply wire to chassis ground
- Damaged/deteriorated potentiometer (internal short)
- Corroded or damaged connector pins or wiring harness
- Water ingress or foreign debris causing short or increased current
- Faulty control module or internal driver fault
- Improper previous repair or pinched wiring
Symptoms
- Diagnostic trouble code B1271 stored in body control/servo module
- Burning smell or warm/hot potentiometer or connector at rest or after operation
- Intermittent or complete loss of position feedback from the servo/potentiometer
- Erratic servo operation or failure of related function (e.g., HVAC flap, gearbox flap, door lock)
- Visible heat damage, melting, or discoloration at connector or wiring
What to check
- Visually inspect potentiometer, servo motor and wiring harness for damage, melting, corrosion, or signs of overheating
- Inspect connector pins for corrosion, bent pins, or evidence of arcing
- With ignition off, check continuity between potentiometer signal/supply wires and chassis ground to identify a short
- Measure resistance of potentiometer (with connector disconnected) and compare to specification
- With connector connected and ignition on, measure reference voltage and signal voltage at the potentiometer connector
- Use a scan tool to monitor potentiometer position values and run any actuator/diagnostic tests available
Signal parameters
- Reference supply (typical): ~5.0 V ±0.5 V (verify vehicle spec) measured between reference and ground
- Signal voltage (position dependent): ~0.5–4.5 V while moving through full travel (with component connected)
- Potentiometer total resistance: manufacturer specific (commonly 1 kΩ–20 kΩ); verify exact spec from wiring diagram
- Expected current draw: very small (milliamps) for the potentiometer; measured high current indicates short/overload
- Resistance from signal wire to ground with connector disconnected: open/high (near infinite). Low resistance (
Diagnostic algorithm
- Read and record freeze frame data and related DTCs with a suitable scan tool; do not rely on one code alone
- Perform a thorough visual inspection of the potentiometer, servo, connector and harness for heat damage, corrosion, pinching or water ingress
- Disconnect battery power if required by vehicle procedure before performing resistance checks
- With the potentiometer connector disconnected, measure resistance between each potentiometer terminal and chassis ground. A low resistance indicates a short to ground—repair wiring
- With connector disconnected, measure potentiometer total resistance across its ends and between wiper and ends; compare to specification. Replace potentiometer if out of spec or shows intermittent/zero resistance
- Reconnect component. With ignition on (engine off), measure reference voltage (5 V) and signal voltage at the connector while moving the actuator manually or via scan-tool command. Abnormal or clamped signal indicates wiring or internal short
- Perform a wiggle test on harness while monitoring signal and looking for intermittent shorts or changes in readings
- If wiring and connector are good but signals are abnormal, isolate by disconnecting at the module side and check for shorts between harness and ground; inspect grounds and harness routing
- If all wiring and component tests are good, suspect module driver fault. Confirm with manufacturer wiring diagrams and consider module bench test or replacement per service instructions
- After repairs, clear codes, perform actuator/position relearn if required, and verify proper operation and that B1271 does not return
Likely causes
- Potentiometer internal failure (short between track and ground)
- Chafed wiring or pinched harness causing contact with ground
- Corroded/contaminated connector at potentiometer or servo motor
- Short in harness caused by routing near sharp edges or heat source
Fault status
Status
Heating detected on servo motor potentiometer circuit due to short to ground. Control module has stored B1271. Inspect potentiometer, wiring and connectors for short/overload.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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