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GM 95018085: The Sensor Behind Your Compressor Cycling

Your A/C compressor only cycles correctly when the HVAC control module knows how cold the evaporator core really is. On GM's Gamma II and D2XX platforms, that feedback comes from one part: the GM Genuine A/C Evaporator Temperature Sensor (P/N 95018085) — a direct-fit, OEM-specification NTC thermistor for the Chevrolet Sonic (2012–2020), Chevrolet Trax (2013–2022), Buick Encore (2013–2022), and Cadillac XT5.

The thermistor senses from -40°C to +125°C with a nominal R25 resistance of approximately 10 kΩ and feeds a 0–5 V analog signal to the HVAC control module for real-time compressor cycling logic. For the 2026 model cycle it remains the primary evaporator frost-prevention feedback loop in GM's HVAC control architecture.

2026 Compliance Snapshot

• CAN-bus 3.0? Yes. The sensor's analog signal is processed through GM's Body Control Module (BCM) and broadcast on the GMLAN/CAN-bus 3.0 architecture for 2026 diagnostics.
• SAE J2842_202606? Yes. The assembly is validated for evaporator core anti-frost protection under SAE J2842_202606 criteria on both R-134a and R-1234yf systems.
• Service life? A projected 2026–2030 lifecycle with a 6-year/100,000-mile durability rating when installed per GM TSB 16-NA-057 specifications.
• Still current? As of the 2026 model year, GM has not issued a replacement part number — 95018085 remains the current-production, OEM-approved sensor for all compatible vehicles.

DTC Mapping: B3933 First, P0530–P0533 Second

B3933 (Evaporator Temperature Sensor Circuit) is the primary diagnostic target for this sensor across all compatible GM vehicles. When frost-induced pressure anomalies are the real trigger, the same failure also sets P0530–P0533 (A/C Refrigerant Pressure Sensor “A” Circuit Range/Performance), so a correct replacement indirectly resolves those codes too.

On 2026 models with GM Global B electrical architecture, B3933 is reported at the Body Control Module (K9 BCM) level and propagated to the Gateway Module for OBD-II compliance. Your scan tool reads it from the BCM, so wiring and calibration checks matter as much as the sensor itself.

Inside the Sensor: NTC Architecture and the 2026 Material Update

Glass-sealed hermetic bead thermistor

The 95018085 uses a precision Negative Temperature Coefficient (NTC) thermistor encapsulated in a high-temperature composite probe housing. For the 2026 model year, GM's supplier chain has transitioned to a glass-sealed hermetic bead design that significantly improves resistance to moisture ingress — the primary failure vector identified in earlier MY 2012–2018 units.

Probe body, lead wires, and connector

Per GM material specification 13596432, the probe body is a PPS (polyphenylene sulfide) composite rated for continuous 125°C exposure, meeting SAE J2842_202606 Section 6.3 material durability requirements for evaporator-mounted sensors in R-1234yf and R-744 refrigerant environments.

Lead wires use cross-linked XLPE insulation rated to 150°C continuous. The connector is a GM Metri-Pack 150 series 2-pin sealed unit, compliant with USCAR-2 Class 3 vibration and IP67 ingress protection standards.

GM 95018085 Specification Table

Failure Symptoms to Watch For

The failure profile is consistent across Sonic, Trax, Encore, and XT5:

• Intermittent A/C cooling loss — the evaporator freezes without temperature feedback and blocks airflow until it thaws.
• Compressor rapid cycling — the clutch engages and disengages every 3–8 seconds.
• B3933 stored in the HVAC module, with or without an illuminated MIL.
• Reduced vent airflow as ice accumulates on the evaporator core.

On 2024–2026 model years equipped with R-1234yf, a failing sensor can also trigger P0530–P0533 through abnormal refrigerant pressure fluctuations during freeze-thaw cycles. The OEM 95018085 sensor addresses these failure modes directly.

Test Before You Replace

Resistance check

Measure resistance across the two sensor terminals at a known ambient temperature. At 25°C (77°F) you should read approximately 10 kΩ ±3%. A shorted sensor reads below 100 Ω; an open circuit reads above 1 MΩ.

PID response check

Monitor the HVAC evaporator temperature PID with a scan tool while applying a heat gun or freeze spray to the probe. The PID should respond smoothly without dropouts. If it reads -40°C or 125°C and does not change, the sensor or its wiring is faulted.

Fitment: Gamma II and D2XX — Not VSS-F

The 95018085 is validated for the Gamma II platform: first-generation Chevrolet Trax through 2022, Buick Encore through 2022, and Chevrolet Sonic through 2020, plus the Cadillac XT5 on D2XX. The second-generation 2024–2026 Chevrolet Trax and Buick Envista ride GM's VSS-F platform with an updated HVAC architecture, so this sensor is not their part.

Verify fitment by VIN lookup or on the product page for the latest compatibility updates. GM's service recommendation: inspect the sensor at 100,000 miles, and replace it proactively whenever evaporator core service is performed.

Related GM Parts: EVAP Purge Valves and the Climate Catalog

HVAC and EVAP faults often surface in the same diagnostic session. If your scan tool also flags the evaporative system, Koeep covers the purge-valve side with the Fuel Tank Evaporator Control Vapor Canister Purge Valve Solenoid 12597341 Fit GM and the 12597341 Fuel Tank Evaporator Control Vapor Canister Purge Valve Solenoid For GM.

For the companion read, see the complete guide to the Evaporator Emission Canister Purge Solenoid Valve 12606684 for Chevy & Cadillac owners, or browse the AC & Heating Parts collection for the wider climate control catalog.

FAQ: GM 95018085 Diagnostics and Ordering