P0137 on a 2017 Kia Sportage
Post-Cat O2 Sensor Low Voltage (Bank 1 Downstream)
P0137 on a 2017 Kia Sportage indicates post-cat o2 sensor low voltage (bank 1 downstream). It usually stays drivable short-term but should be diagnosed promptly. The most common cause is downstream o2 signal wire shorted to ground or open (typically $80–$350). Confirm the root cause before replacing parts.
What does P0137 mean on a 2017 Kia Sportage?
P0137 is set when the Bank 1 downstream oxygen sensor reports a voltage below the calibrated minimum — typically under about 0.1 V — for an extended period. Bank 1 is the cylinder bank containing cylinder number 1. Sensor 2 is the sensor AFTER the catalytic converter, not the one threaded into the exhaust manifold. A healthy downstream sensor on a warm engine holds a relatively steady 0.6–0.8 V because the catalyst smooths out the rich / lean swings coming from the engine, so a reading pinned low means an open or shorted-to-ground signal circuit, a failed sensor, or fresh air getting into the exhaust ahead of the sensor.
The symptoms, causes, and diagnostic steps below describe P0137 itself, so they read the same on nearby Kia Sportage model years. Powertrain and trim details vary year to year — confirm the specifics against your own vehicle before buying parts.
Is it safe to drive a 2017 Kia Sportage with P0137?
In most cases a 2017 Kia Sportage stays drivable for short trips with P0137 active, but diagnose and repair it promptly. This is a moderate-severity code — ignoring it can lead to further damage or a failed emissions test.
What are the symptoms of P0137 on a 2017 Kia Sportage?
- Check Engine Light is illuminated
- Catalyst readiness monitor will not complete
- Often no drivability symptoms at all
- Possible slight reduction in fuel economy
- Vehicle will fail emissions / smog testing
- Sometimes accompanied by P0171 if a genuine lean condition is present
What causes P0137 on a 2017 Kia Sportage?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Downstream O2 signal wire shorted to ground or open | Most common | $80–$350 |
| Failed Bank 1 downstream O2 sensor (stuck low) | Most common | $150–$450 |
| Exhaust leak ahead of the downstream sensor drawing in fresh air | Common | $100–$500 |
| Corroded downstream O2 sensor connector | Common | $30–$200 |
| Damaged sensor pigtail from a previous exhaust or suspension repair | Occasional | $80–$300 |
| Genuine lean condition from a vacuum leak reaching the catalyst Here the sensor is telling the truth — fix the lean condition, not the sensor. | Occasional | $80–$600 |
| Failed PCM input for the downstream sensor circuit | Rare | $400–$1,500 |
Cost ranges are editorial estimates for parts and labor at an independent U.S. shop — not quotes. What you actually pay moves with your region, the shop's hourly rate, which engine you have, and how much diagnostic time the job takes. Dealer service departments typically sit above these ranges.
How to diagnose this on a 2017 Kia Sportage
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Confirm you are at the right sensor before touching anything
Bank 1 Sensor 2 is downstream of the catalytic converter on the bank containing cylinder number 1. On an inline engine there is only one bank, so it is simply the sensor after the cat. On a V engine you have to establish which bank holds cylinder 1 first. Replacing the upstream sensor by mistake is the single most common wasted repair on this code.
Tools: Vehicle-specific service information, Vehicle lift or jack stands
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Read fuel trims to separate a real lean condition from a sensor fault
Check Bank 1 long-term fuel trim at idle and at 2500 RPM. Near zero means the engine is fuelling correctly and the sensor or its wiring is lying. Trim at +15 % or higher means the engine really is lean, the sensor is reporting honestly, and your job is to find the vacuum or exhaust leak — not to buy an O2 sensor.
Tools: Scan tool with live fuel trim PIDs
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Disconnect the sensor and look for bias voltage
Unplug the downstream sensor. With the key on, the scan tool PID should show the ECM's bias voltage, usually around 0.4–0.5 V. If the reading stays pinned at zero with the sensor disconnected, the signal wire is shorted to ground somewhere between the connector and the PCM, and a new sensor will not change a thing.
Tools: Scan tool, Multimeter
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Inspect the harness and connector under the vehicle
The downstream sensor and its harness live under the car in road spray and salt. Trace the wiring from the sensor body back to the chassis connector looking for melted insulation where it has touched the exhaust, chafing against the underbody, and rodent damage. Open the connector and check for water and green corrosion.
Tools: Flashlight, Inspection mirror, Electrical contact cleaner
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Find exhaust leaks between the catalyst and the sensor
A pinhole or a leaking flange gasket ahead of the downstream sensor lets fresh air into the exhaust stream, and the sensor correctly reports the oxygen it sees — as a permanently low voltage. Listen along the pipe with the engine cold, or use a smoke machine on the exhaust to make small leaks visible.
Tools: Mechanic's stethoscope, Smoke machine (optional), Flashlight
NHTSA complaints & recalls for the 2017 Kia Sportage
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2017 Kia Sportage. Use these to gauge how common a problem is on your specific vehicle before you start chasing Kia Sportage diagnostics.
- ENGINE 211
- POWER TRAIN 40
- UNKNOWN OR OTHER 68
- ELECTRICAL SYSTEM 61
- SERVICE BRAKES 24
4 active recalls
- FUEL SYSTEM, GASOLINE:DELIVERY:HOSES, LINES/PIPING, AND FITTINGS Dec 2018
Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign. The h…
NHTSA campaign 18V907000 - SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP:CONTROL UNIT/MODULE Mar 2021
Kia Motors America (Kia) is recalling certain 2017-2021 Sportage and Cadenza vehicles. The electrical circuit in the Hydraulic Electronic Control Unit (HECU) may short-circuit, which can cause a fire in the engine compartment.…
NHTSA campaign 21V137000 - TRAILER HITCHES Nov 2016
Kia Motors America (Kia) is recalling certain model year 2016-2017 Sorento vehicles manufactured October 27, 2014, to August 25, 2016, and 2017 Sportage vehicles manufactured December 10, 2015, to August 26, 2016. The affected vehicles are equipped with an accessory trailer hitc…
NHTSA campaign 16V862000 - TRAILER HITCHES Sep 2022
Kia America, Inc. (Kia) is recalling certain 2016-2022 Sorento, 2021-2022 Sorento Hybrid (HEV), 2022-2023 Sorento Plug-In Hybrid (PHEV), and 2017-2022 Sportage vehicles equipped with a tow hitch harness installed as original equipment, or purchased as an accessory through a Kia d…
NHTSA campaign 22V703000
How do I fix P0137 on a 2017 Kia Sportage?
- Replace the Bank 1 downstream O2 sensor with an OEM part
- Repair the shorted-to-ground or open O2 signal wire
- Repair exhaust leaks between the catalyst and the downstream sensor
- Clean or replace the corroded downstream sensor connector
- Repair vacuum leaks if fuel trims confirm a genuine lean condition
Engines in the 2017 Kia Sportage
The 2017 Kia Sportage was offered with the 2.0L 4-cylinder and 2.4L 4-cylinder engines. Which one you have changes where P0137 is most likely to originate, so confirm your engine before ordering parts.
Engine data: EPA fueleconomy.gov.
Bank 1 Sensor 2 means the sensor after the catalytic converter
This is worth being pedantic about, because getting it wrong sends you to the wrong part of the exhaust:
- Sensor 1 — upstream, before the catalyst, usually threaded into the exhaust manifold or the downpipe. This is the sensor that drives fuel control.
- Sensor 2 — downstream, after the catalyst, underneath the vehicle. This is the sensor that monitors whether the catalyst is still working.
P0137 is a Sensor 2 code. If you are reaching down past the manifold, you are at the wrong sensor.
Is the sensor lying, or is the engine actually lean?
Fuel trim answers this in about thirty seconds, and it decides the entire repair:
- Trim near zero, P0137 alone → the engine is fuelling correctly. The sensor or its circuit is at fault. Test the wiring, then replace the sensor.
- Trim high positive, often with P0171 → the engine really is running lean and the downstream sensor is honestly reporting it. Replacing the sensor fixes nothing. Go find the vacuum leak, the exhaust leak, or the fuel delivery problem.
Why the car drives fine with P0137
The downstream sensor’s primary job is monitoring catalyst efficiency, not controlling fuel delivery — that is the upstream sensor’s role. It contributes only a slow secondary correction to fuel trim. So a failed downstream sensor almost always shows up as a light on the dash and a failed emissions test, not as a car that runs badly. That makes P0137 non-urgent from a drivability standpoint, but it does not make it optional: the catalyst monitor cannot complete while it is set, and most emissions programmes treat an incomplete monitor as a failure.
Buy the sensor once
Aftermarket oxygen sensors at a fraction of OEM pricing have a real track record of setting the same code again within months. The downstream sensor is a comparison device rather than a precision measurement device, so it is slightly more forgiving than the upstream one — but not forgiving enough to be worth the second job. Bosch, Denso, or NTK in the exact part number listed for your year, make, model, engine, and emissions package.
P0137 on a 2017 Kia Sportage: frequently asked questions
What does diagnostic trouble code P0137 mean on a 2017 Kia Sportage?
P0137 is set when the Bank 1 downstream oxygen sensor reports a voltage below the calibrated minimum — typically under about 0.1 V — for an extended period. Bank 1 is the cylinder bank containing cylinder number 1. Sensor 2 is the sensor AFTER the catalytic converter, not the one threaded into the exhaust manifold. A healthy downstream sensor on a warm engine holds a relatively steady 0.6–0.8 V because the catalyst smooths out the rich / lean swings coming from the engine, so a reading pinned low means an open or shorted-to-ground signal circuit, a failed sensor, or fresh air getting into the exhaust ahead of the sensor.
What are the symptoms of P0137 on a 2017 Kia Sportage?
Check Engine Light is illuminated. Catalyst readiness monitor will not complete. Often no drivability symptoms at all. Possible slight reduction in fuel economy. Vehicle will fail emissions / smog testing. Sometimes accompanied by P0171 if a genuine lean condition is present
What causes P0137 on a 2017 Kia Sportage?
Downstream O2 signal wire shorted to ground or open (most-common). Failed Bank 1 downstream O2 sensor (stuck low) (most-common). Exhaust leak ahead of the downstream sensor drawing in fresh air (common). Corroded downstream O2 sensor connector (common). Damaged sensor pigtail from a previous exhaust or suspension repair (occasional). Genuine lean condition from a vacuum leak reaching the catalyst (occasional). Failed PCM input for the downstream sensor circuit (rare)
Is it safe to drive a 2017 Kia Sportage with P0137?
In most cases a 2017 Kia Sportage stays drivable for short trips with P0137 active, but it should be diagnosed and repaired promptly — this is a moderate-severity code. Ignoring it can lead to further damage or a failed emissions test.