P0137 on a 2017 Jeep Grand Cherokee
Post-Cat O2 Sensor Low Voltage (Bank 1 Downstream)
P0137 on a 2017 Jeep Grand Cherokee 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 Jeep Grand Cherokee?
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 Jeep Grand Cherokee 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 Jeep Grand Cherokee with P0137?
In most cases a 2017 Jeep Grand Cherokee 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 Jeep Grand Cherokee?
- 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 Jeep Grand Cherokee?
| 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 Jeep Grand Cherokee
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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 Jeep Grand Cherokee
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2017 Jeep Grand Cherokee. Use these to gauge how common a problem is on your specific vehicle before you start chasing Jeep Grand Cherokee diagnostics.
- ENGINE 99
- POWER TRAIN 87
- ELECTRICAL SYSTEM 86
- UNKNOWN OR OTHER 76
- FUEL/PROPULSION SYSTEM 30
6 active recalls
- ELECTRICAL SYSTEM:WIRING May 2018
Chrysler (FCA US LLC) is recalling certain 2014-2018 Dodge Journey, Charger and Durango, RAM 2500, 3500, 3500 Cab Chassis (more than 10,000lb), 4500 Cab Chassis and 5500 Cab Chassis, Jeep Cherokee and Grand Cherokee and Chrysler 300, 2014-2019 RAM 1500, 2015-2018 Dodge Challenger…
NHTSA campaign 18V332000 - ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE) Nov 2020
Chrysler (FCA US LLC) is recalling certain 2014-2019 Jeep Grand Cherokee vehicles equipped with the 3.0L EcoDiesel engines. The Exhaust Gas Recirculation (EGR) cooler may crack and allow pre-heated vaporized coolant to enter the EGR system. This mixture may combust inside the…
NHTSA campaign 20V699000 - EQUIPMENT Sep 2016
Chrysler (FCA US LLC) is recalling certain model year 2017 Jeep Grand Cherokee manufactured August 8, 2016 through August 16, 2016. In the affected vehicles, the rear tow hook bracket or tow eye bracket may be loose.…
NHTSA campaign 16V686000 - ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:TURBO/SUPERCHARGER Oct 2017
Accessible Technologies, Inc. (ATI) is recalling certain ProCharger Superchargers, model numbers AB037A-100, AB037A-100P, and A037A-100B, sold for installation on 2012-2017 Jeep Grand Cherokee SRT8 and SRT vehicles. The supercharger mounting bracket may contact and damage the AB…
NHTSA campaign 17E061000
How do I fix P0137 on a 2017 Jeep Grand Cherokee?
- 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 Jeep Grand Cherokee
The 2017 Jeep Grand Cherokee was offered with the 3.6L 6-cylinder, 5.7L 8-cylinder and 6.4L 8-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 Jeep Grand Cherokee: frequently asked questions
What does diagnostic trouble code P0137 mean on a 2017 Jeep Grand Cherokee?
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 Jeep Grand Cherokee?
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 Jeep Grand Cherokee?
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 Jeep Grand Cherokee with P0137?
In most cases a 2017 Jeep Grand Cherokee 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.