P0037 on Subaru
HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
P0037 on Subaru vehicles indicates ho2s heater control circuit low (bank 1 sensor 2). Au7o has documented this code across 1 Subaru model — most commonly on Forester. The PCM detects low voltage (short to ground or open) in the heater control circuit of the downstream O2 sensor on Bank 1, Sensor 2. Typical repair costs on Subaru range from $150 to $450, depending on the specific model and root cause.
Common Causes of P0037
- •Open/short to ground in heater wiring
- •Failed O2 sensor heater
- •Corroded connector
- •Blown fuse
P0037 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 P0037 across all makes →Frequently Asked Questions
What does P0037 mean on Subaru?▼
P0037 stands for "HO2S Heater Control Circuit Low (Bank 1 Sensor 2)." The PCM detects low voltage (short to ground or open) in the heater control circuit of the downstream O2 sensor on Bank 1, Sensor 2. On Subaru specifically, this code is documented across 1 model.
What causes P0037 on Subaru vehicles?▼
Common causes on Subaru: Open/short to ground in heater wiring, Failed O2 sensor heater, Corroded connector, Blown fuse. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0037 on a Subaru?▼
Repair costs on Subaru range from $150 to $450, depending on the specific model and root cause.
Which Subaru models have P0037 documented?▼
Au7o has documented P0037 on 1 Subaru model: Forester.