Code
B1288
Other
B — Body
Servo Motor Potentiometer Airintake Right Circuit Failure
AI status
Completed
Completed
100%
Causes
- Open or short in the potentiometer signal wiring
- Poor connector contact or corrosion at the actuator or control module connector
- Failed servo motor potentiometer or internal actuator electronics
- Water ingress or physical damage to the actuator
- Control module fault or software/firmware issue (less common)
Symptoms
- HVAC right-side air intake or blend door not responding or stuck
- Incorrect air temperature or airflow from right-side vents
- DTC illuminated (service or HVAC warning) and possible limited HVAC operation
- Audible clicking or unusual noise from the actuator
- Intermittent operation of the right-side vent flaps
What to check
- Retrieve all stored DTCs and freeze-frame data; note conditions when code set
- Visually inspect right intake actuator, linkage, and harness for damage or contamination
- Wiggle-test wiring and connectors while monitoring live data for intermittent changes
- Measure reference voltage, ground continuity, and signal voltage at the actuator connector
- Check actuator operation via diagnostics (command motor through scan tool) and observe potentiometer feedback
Signal parameters
- Typically a 3-wire potentiometer: 5 V reference, ground, and variable signal (0–5 V) — signal should move smoothly as actuator rotates
- At mid-position expect approximately 2.0–3.0 V (varies by manufacturer)
- No short to battery (near 12 V) or to ground should be present on the signal wire
- Resistance across potentiometer terminals typically in the kilo-ohm range (manufacturer-specific)
- Some actuators use PWM or digital feedback; expected frequency or data rate must be checked against manufacturer specs
Diagnostic algorithm
- Record code and clear then re-run to confirm repeatability.
- Visually inspect the right air-intake actuator, linkage, and harness for damage, water, or debris. Repair any mechanical binding.
- With ignition ON (engine off unless specified), backprobe actuator connector: verify 5 V reference (or specified reference), good ground, and stable signal voltage. Move actuator manually and observe signal change.
- If signal is stuck, open, or noisy, check continuity between actuator connector and the control module connector for short or open. Repair broken wires or poor connectors.
- Wiggle the harness and connectors while watching live signal for intermittent faults. Repair or secure harness as needed.
- Command the actuator using a scan tool to drive through full travel while monitoring feedback. If commanded motion produces no correct feedback but motor runs, suspect internal potentiometer failure.
- If wiring and connector are good but signal is incorrect, replace the right air-intake servo motor (actuator).
- After repair, clear codes and perform a full HVAC self-test or actuator calibration if required by the manufacturer. Verify proper operation and that code does not return.
- If issue persists, test or replace the control module or consult manufacturer technical service information for software updates and known issues.
Likely causes
- Broken/damaged harness or chafed wiring to the right air intake actuator
- Corroded or loose connector pins at the actuator
- Worn or failed potentiometer inside the HVAC/air intake servo motor
- Rod/gear binding that prevents actuator movement and produces erratic signal
- Short to battery or ground on the signal or reference wire
Fault status
Status
Right air-intake servo motor potentiometer circuit fault — signal out of range or open/short detected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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