B1288

Code

LAND ROVER B — Body

Right air intake servo motor potentiometer - circuit failure

Brand: LAND ROVER

Type: B — Body

Views: UK: 15 EN: 30 RU: 19

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Page language: EN

Causes

Open or short in potentiometer signal, reference or ground circuit
Poor/loose/corroded connector at the intake servo motor
Failed potentiometer inside the servo motor assembly
Mechanical binding or damage to the right intake flap or servo
Water ingress or corrosion in the actuator or harness
Blown fuse or poor power/ground to HVAC actuator

Symptoms

HVAC right intake flap stuck or not responding to mode changes
Incorrect airflow distribution or inability to select fresh/recirculate paths
HVAC system runs but does not move to commanded positions
Audible clicking/grinding from dash area when changing vents
DTC B1288 present and may be accompanied by related HVAC codes
Intermittent operation or only working after tapping the actuator

What to check

Read and record freeze frame and any related DTCs with a diagnostic scanner
Perform actuator exercise (active tests) from scan tool and watch reported position
Visually inspect connector and wiring for corrosion, damage, or water entry
Wiggle harness while exercising actuator to reproduce fault
Check fuses/power supply and ground to HVAC actuators
Backprobe connector to measure reference voltage, ground, and signal while moving actuator

Signal parameters

Potentiometer typically uses 3 wires: 5 V reference, signal (position), and ground
Reference voltage ~5 V (check vehicle spec) with key on, engine off
Position signal varies proportionally between ~0–5 V as the flap moves (exact range depends on design)
Ground should be near 0 V with low resistance to chassis ground
Resistance between potentiometer terminals changes smoothly as actuator shaft is moved (no abrupt jumps)

Diagnostic algorithm

Verify the complaint and retrieve codes/ freeze frame using a capable scan tool. Note any related HVAC codes.
Use the scan tool to command the right intake servo through its full range; observe reported position and listen for unusual noises.
Visually inspect the servo, connector and harness for corrosion, water ingress, chafing or pin damage. Repair any obvious damage.
With harness connected, backprobe the connector. With ignition on, confirm reference voltage (~5 V) and good ground at the connector. If missing, trace fuse/power/ground.
While commanding the actuator, monitor the potentiometer signal voltage. It should change smoothly and proportionally with movement. Intermittent or out‑of‑range values indicate wiring or potentiometer faults.
If wiring and power/ground are good but signal is erratic, remove the servo and measure potentiometer resistance across terminals while manually moving the gear. Look for jumpy readings or infinite resistance.
Check continuity between the servo connector and the HVAC module connector to rule out harness breaks or shorts to chassis/battery.
Repair/replace damaged wiring or connector pins. If potentiometer inside the servo is faulty, replace the right air intake servo motor assembly.
After repair, clear codes and recheck by running the actuator through its full range and verifying normal operation and that the DTC does not return.

Likely causes

Disconnected or corroded connector at the right intake servo
Broken or chafed wiring in harness to the servo potentiometer
Failed potentiometer within the right air intake servo assembly
Mechanical restriction preventing the actuator from reaching expected positions

Fault status

⚠️ Status

Right air intake servo motor potentiometer - circuit failure

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-1.5 hours

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B1288 — Right air intake servo motor potentiometer - circuit failure