P0131 on Chevrolet: How to Diagnose & Fix
O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
1 Chevrolet model · 1 documented issue · $50-$500 repair
P0131 on Chevrolet by model: symptoms, diagnosis and fix
On the Sonic with the 1.4L turbo engine (RPO LUJ/LUV), the best-documented cause of a check engine light is a cracked diaphragm in the PCV (positive crankcase ventilation) pressure regulator valve. That valve is part of the plastic camshaft cover. When the diaphragm cracks, extra air gets drawn into the engine intake. The engine can then run rough, especially at idle, and the check engine light comes on. GM says the code is usually P0171 (fuel trim lean) or another airflow-related code. One 2014 Sonic owner with about 54,000 miles reported P0106 and P1101, a rough idle, and a loud "vacuum cleaner" sound from the top of the engine. GM created two special-coverage programs for this failure: N202299080 for the 2012-2014 Sonic and N192210230 for the 2015 Sonic, both with the 1.4L engine. Neither program lists the 1.8L engine or the 2016 Sonic.
Common Symptoms
- Check engine light with P0171 (fuel trim lean) or another airflow code such as P0106 or P1101
- Rough running, especially at idle
- Noise from the PCV valve on top of the engine (one owner described a loud vacuum-cleaner sound)
- Noise at the PCV valve gets quieter or stops when the oil dipstick is pulled
- Vacuum pulls a tissue against the vent on the front of the PCV valve
How to Fix
1) Read the stored codes. On a 1.4L turbo, P0171, P0106, P1101 or another lean or airflow code points toward the PCV valve. 2) Do GM's quick check. Remove the plastic engine cover and make sure the oil dipstick is fully seated and the oil fill cap is tight. With the engine running, listen for noise from the PCV valve on top of the camshaft cover. If you hear noise, see whether it gets quieter or stops when you pull the dipstick, then put the dipstick back in. Then hold a piece of tissue near the vent on the front of the PCV valve. If the tissue gets sucked against the vent and held there, vacuum is present. GM says to replace the camshaft cover when the valve makes noise and vacuum is present at the vent. 3) The repair is a new camshaft cover, which includes the PCV valve. GM lists part 25198877 and tells dealers to confirm the correct cover by VIN. 4) Check your coverage. Special Coverage N202299080 (2012-2014 Sonic) and N192210230 (2015 Sonic) cover this repair at a GM dealer for 10 years or 120,000 miles from the date the car was first put in service, whichever comes first, regardless of owner. The 10-year limit has now passed for many of these cars, so give the dealer your VIN to confirm. The programs cover only a leaking PCV valve, not oil leaks from the cover. The deadlines to claim reimbursement for repairs you already paid for have passed: July 31, 2020 for the 2015 program and August 31, 2021 for the 2012-2014 program. If the PCV check passes, the programs don't cover any further diagnosis, and the light has a different cause. Diagnose it from the specific code.
Sources for this issue (6)
- NHTSA recalls for the 2012 Chevrolet Sonic (7 campaigns)nhtsa
- 2012 Chevrolet Sonic problems - CarComplaints.comarticle
- GM Special Coverage N202299080 - Camshaft Cover Replacement (2012-2014 Sonic, 1.4L LUJ/LUV)tsb
- GM Special Coverage N192210230 - Camshaft Cover Replacement (2015 Sonic, 1.4L LUV)tsb
- CarComplaints: 2015 Chevrolet Sonic TSB N192210230tsb-summary
- Chevy Sonic 1.4L Turbo PCV fix (error codes P0106 & P1101)owner-report
P0131 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0131 mean on a Chevrolet?
P0131 stands for "O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)." This code means the upstream oxygen (O2) sensor on Bank 1, Sensor 1 — located before the catalytic converter — is reporting an abnormally low voltage, which the computer reads as a persistently lean exhaust (too much oxygen). The computer uses this sensor to fine-tune the air-fuel mixture, and a stuck-low signal disrupts that feedback. The low reading can come from an actual lean condition in the engine or from a faulty sensor or its wiring. Symptoms may include rough running, hesitation, and reduced fuel economy. On Chevrolet it is documented across 1 model: Sonic.
What are the most common causes of P0131?
The most common causes of P0131 are: Vacuum or intake air leak (true lean condition), Failed or contaminated upstream O2 sensor, Exhaust leak ahead of the sensor, Low fuel pressure or weak/clogged fuel injectors, Corroded or loose O2 sensor connector, Damaged or shorted-to-ground sensor wiring, Dirty mass airflow sensor skewing fuel trims, Faulty PCM/ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0131 on a Chevrolet?
Published repair estimates on Chevrolet range from $50 to $500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.