P0037: HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
Can you still drive? Yes, this is a low-severity code. The vehicle will drive normally and no engine damage will occur.
What Does P0037 Mean?
Code P0037 means the ECM has detected that the heater circuit voltage for the downstream oxygen sensor on bank 1 is below the expected range. This usually indicates a short to ground in the heater wiring or a failed heater element with abnormally low resistance. The sensor cannot reach proper operating temperature under this condition.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Short to ground in O2 sensor heater wiring
- Internal short in O2 sensor heater element
- Corroded ground wire or connector
- Damaged wiring harness near exhaust heat
- Faulty ECM heater driver (rare)
Symptoms
- Check engine light on
- Possible companion code P0420
- No noticeable performance loss
- Slightly higher tailpipe emissions
Diagnostic Steps
- 1Measure heater circuit resistance at the sensor connector and compare to spec
- 2Check for short to ground on the heater signal wire
- 3Inspect wiring harness routing near exhaust components for heat damage
- 4Check connector pins for corrosion or bent terminals
- 5Swap sensor with known-good unit if resistance checks are inconclusive
- 6Test ECM heater control output with a scan tool bi-directional test
Recommended Parts & Tools
downstream oxygen sensor
O2 sensor socket
wiring repair harness
digital multimeter
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $50 - $300 |
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Frequently Asked Questions
What is the difference between P0036 and P0037?
P0036 is a general heater circuit malfunction while P0037 specifically indicates the circuit voltage is low, usually meaning a short to ground in the wiring or sensor.
Can heat damage cause P0037?
Yes, the downstream O2 sensor wiring runs near hot exhaust components and can be damaged by heat over time, causing shorts or opens in the heater circuit.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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