Code
B1288
FIAT
B — Body
Right air intake potentiometer servo circuit
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between control module and right intake servo potentiometer
- Corroded, loose or damaged connector at the actuator or control module
- Failed potentiometer inside the servo/actuator
- Failed servo motor or internal gearbox preventing correct potentiometer movement
- Mechanical binding or obstruction of the intake door linkage
- Faulty climate control module or body control module (less common)
Symptoms
- HVAC air distribution not switching to/from fresh air/recirculation correctly
- Inability to change intake position (stuck on recirculate or fresh air)
- Unusual noise from HVAC area (motor stalling or grinding)
- Climate control warning or ECU stored DTC B1288
- Intermittent operation of intake door or delayed response
What to check
- Scan for stored and pending HVAC/body codes and note freeze frame data
- Visual inspection of actuator, harness and connector for damage or corrosion
- Attempt to operate intake control while observing actuator movement and listening for noise
- Backprobe actuator connector and measure power, ground and feedback signal with ignition on and while commanding actuator
- Wiggle test harness while monitoring signal for intermittent changes
- Inspect intake door linkage for binding or obstructions
Signal parameters
- Reference voltage to potentiometer: ~5 V (check vehicle specification)
- Potentiometer feedback (wiper) voltage: typically ~0.5 V to ~4.5 V depending on door position
- Ground continuity: near 0 ohms to chassis ground
- Expected change in feedback voltage when commanding actuator: monotonic change across full travel (approx. 0.5–4.5 V)
- No continuity or open/short to power/ground indicates wiring or internal potentiometer fault
Diagnostic algorithm
- Retrieve all HVAC/body module fault codes and notes. Clear codes after initial verification only if instructed by procedure.
- Perform visual inspection of right intake actuator, connector and wiring for damage, corrosion, or signs of water ingress. Repair as needed.
- With ignition ON (engine off unless specified), backprobe actuator connector: confirm 5 V reference, ground, and feedback (wiper) voltage. If no reference or ground, inspect wiring to control module.
- Command intake actuator through climate controls or using a diagnostic tool while observing feedback voltage. Verify feedback changes smoothly across travel. If feedback is fixed, suspect open/short or failed potentiometer.
- Perform wiggle test on wiring and connector while monitoring feedback and watching for intermittent faults. Repair broken wires, crimps or corroded pins.
- Remove actuator and bench-test if applicable (measure potentiometer resistance or move shaft and observe voltage change). Inspect gears and motor for mechanical failure.
- If actuator is defective (no feedback change, internal open/short, seized motor, damaged gears), replace actuator. If wiring or connector faults found, repair and apply corrosion protection.
- After repair or replacement, clear codes and perform functional test of HVAC intake operation through full range. Re-scan to confirm code does not return.
- If wiring and actuator test OK but code persists, suspect control module fault and consult manufacturer diagnostic procedures for module testing or reflash.
Likely causes
- Damaged connector or wiring (broken wire, pin corrosion)
- Failed potentiometer inside the right intake servo
- Actuator motor seized or gear stripped preventing correct position feedback
- Mechanical obstruction preventing door movement
Fault status
Status
Right air intake potentiometer servo circuit fault — position feedback out of range or missing; service connector, wiring, or actuator.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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