Code
B150F15
VOLVO
B — Body
Air Discharge Temperature Sensor. Circuit Short To Battery or Open
Views:
UK: 13
EN: 17
RU: 16
AI status
Completed
Completed
100%
Causes
- Open circuit (broken wire, disconnected connector)
- Short to battery (wiring pin contacting +12V)
- Short to ground (wiring chafe or pin short)
- Failed/disconnected air discharge temperature sensor (thermistor)
- Corroded or pushed‑out connector pins
- Water ingress or contamination at connector
Symptoms
- DTC B150F15 stored (check with scan tool)
- HVAC may run in limp mode or display incorrect cabin temperature control
- Air temperature at vents not regulated correctly (too cold/too warm)
- Inconsistent or erratic HVAC behavior, compressor cycling oddities
- Possible warning or message in climate control display
What to check
- Read freeze‑frame and live data with a capable scan tool; note sensor voltage/resistance and related freeze data
- Visual inspection of sensor, connector and wiring for damage, corrosion, water or pin deformation
- Wiggle harness while monitoring live data to look for intermittent faults
- Measure sensor connector pins for battery voltage, ground and signal using a multimeter
- Check for continuity between sensor signal and HVAC/BCM harness connector and for unintended continuity to +12V
- Disconnect sensor and check harness side for short to battery or open
Signal parameters
- Sensor type: typically an NTC thermistor (resistance changes with temperature) — model specific
- Open circuit: signal reads OL or very high resistance (>>10 kΩ depending on design)
- Short to battery: signal/feeding pin measures near vehicle battery voltage (~12 V) when pin should not
- Short to ground: signal measures near 0 V
- Normal operation: signal voltage or resistance varies with temperature (low temp = higher resistance for NTC; confirm values in factory documentation)
Diagnostic algorithm
- Connect an advanced scan tool and confirm B150F15 is current or stored. Record freeze frame and live data for the air discharge temperature sensor.
- Perform a visual inspection: check the sensor, connector and wiring routing for damage, corrosion or signs of water ingress.
- Backprobe the sensor connector with ignition ON. Measure reference supply (if present), signal voltage and ground. Note if signal pin reads battery voltage (short to battery) or open/OL.
- With harness disconnected from sensor, check continuity of the signal wire to the HVAC/BCM connector. Check for continuity to battery (+12V) and to ground. Repair any shorts or opens found.
- Measure sensor resistance at ambient temperature and compare behavior by warming/cooling the sensor (with hot air or ice) — resistance should change smoothly. Replace sensor if fixed resistance or no change.
- Repair or replace damaged wiring, connectors or pins. Use dielectric grease on connectors if water ingress was present and secure routing to prevent chafing.
- After repair, clear codes and retest. Verify the sensor returns valid live values and the code does not return under normal operating conditions.
- If wiring and sensor test good and fault persists, investigate HVAC control module inputs/grounds and consider module diagnosis per factory procedures.
Likely causes
- Damaged harness between sensor and HVAC/BCM causing open or short to battery
- Connector corrosion or bent/pushed pins causing intermittent contact or short
- Failed thermistor inside the discharge temperature sensor
- Aftermarket work or repairs that pinched/ran wiring against body metal
- Loose or corroded ground or supply at HVAC control module
Fault status
Status
Air discharge temperature sensor circuit indicates short to battery or open. Fault stored in HVAC/Body module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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