P0030 on Subaru
HO2S Heater Control Circuit (Bank 1 Sensor 1)
P0030 on Subaru vehicles indicates ho2s heater control circuit (bank 1 sensor 1). Au7o has documented this code across 1 Subaru model — most commonly on Forester. The PCM detects a fault in the heater control circuit of the heated oxygen sensor (HO2S) at Bank 1, Sensor 1 (upstream). The internal heater that brings the sensor to operating temperature is not responding as expected. Typical repair costs on Subaru range from $150 to $450, depending on the specific model and root cause.
Common Causes of P0030
- •Failed O2 sensor heater element
- •Blown fuse or open in heater circuit
- •Corroded/loose connector
- •PCM heater driver fault
P0030 on Subaru by Model
Subaru Forester(1 issue)
- Front Air/Fuel Ratio (Wideband O2) Sensor Heater Circuit Failure — P0031/P00372009-2018
Foresters commonly throw front oxygen/air-fuel-ratio sensor heater-circuit codes (P0031 low, P0037 downstream) as the sensors age. The sensors live on the hot exhaust, so the wiring harness near them turns brittle and chafes, and the internal heater element degrades. The result is an illuminated check-engine light, slightly richer/leaner running while the heater is cold, and a guaranteed emissions-test failure. Many owners replace the sensor only to find the real fault is damaged harness wiring at the connector.
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View P0030 across all makes →Frequently Asked Questions
What does P0030 mean on Subaru?▼
P0030 stands for "HO2S Heater Control Circuit (Bank 1 Sensor 1)." The PCM detects a fault in the heater control circuit of the heated oxygen sensor (HO2S) at Bank 1, Sensor 1 (upstream). The internal heater that brings the sensor to operating temperature is not responding as expected. On Subaru specifically, this code is documented across 1 model.
What causes P0030 on Subaru vehicles?▼
Common causes on Subaru: Failed O2 sensor heater element, Blown fuse or open in heater circuit, Corroded/loose connector, PCM heater driver fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0030 on a Subaru?▼
Repair costs on Subaru range from $150 to $450, depending on the specific model and root cause.
Which Subaru models have P0030 documented?▼
Au7o has documented P0030 on 1 Subaru model: Forester.