P0136 on a 2022 GMC Sierra 1500
Post-Cat O2 Sensor Circuit Fault (Bank 1)
P0136 on a 2022 GMC Sierra 1500 indicates post-cat o2 sensor circuit fault (bank 1). It usually stays drivable short-term but should be diagnosed promptly. The most common cause is failed bank 1 downstream o2 sensor (typically $150–$450). Confirm the root cause before replacing parts.
What does P0136 mean on a 2022 GMC Sierra 1500?
P0136 is set when the ECM detects a general circuit fault on the Bank 1 downstream (post-catalyst) oxygen sensor. Unlike the more specific P0137 (low voltage), P0138 (high voltage), or P0140 (no activity), P0136 is the generic circuit code that covers wiring issues, intermittent connection problems, or signals that go outside expected ranges in a way that doesn't fit a more specific fault category.
This guide covers P0136 across the 2020-2024 GMC Sierra 1500 generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2020 through 2024.
Is it safe to drive a 2022 GMC Sierra 1500 with P0136?
In most cases a 2022 GMC Sierra 1500 stays drivable for short trips with P0136 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 P0136 on a 2022 GMC Sierra 1500?
- Check Engine Light is illuminated
- Catalyst readiness monitor will not complete
- Possible slight reduction in fuel economy
- Often no drivability symptoms
- Vehicle will fail emissions / smog testing
What causes P0136 on a 2022 GMC Sierra 1500?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Failed Bank 1 downstream O2 sensor | Most common | $150–$450 |
| Damaged sensor wiring (chafed against exhaust) | Common | $80–$350 |
| Corroded O2 sensor connector | Common | $30–$200 |
| Exhaust leak upstream of the downstream sensor | Occasional | $100–$500 |
| Damaged or compressed sensor pigtail from a previous repair | Occasional | $80–$300 |
| Failed PCM input (rare) | Rare | $400–$1,500 |
How to diagnose this on a 2022 GMC Sierra 1500
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Read all O2-related codes to refine the picture
P0136 alone is generic. With P0137 it points at low voltage specifically; with P0138 at high voltage; with P0140 at no activity at all; with P0141 at the heater. Cross-referencing tells you whether the diagnostic should target wiring, sensor element, or heater.
Tools: Scan tool with full code retrieval
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Inspect the sensor wiring
Trace the downstream sensor's harness from the sensor body back to the chassis connector. Look for melted insulation (from exhaust contact), chafing against suspension components, or rodent damage. Repair before replacing the sensor.
Tools: Flashlight, Inspection mirror, Wire repair supplies
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Test the sensor connector
Disconnect and inspect for water intrusion, corrosion, bent pins. Clean with electrical contact cleaner. The downstream connector sits under the vehicle and gets road spray; corrosion is common after a few salt-belt winters.
Tools: Electrical contact cleaner, Magnifying glass
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Graph the sensor signal
With engine warm and held at 2500 RPM, watch the Bank 1 downstream O2 voltage. A healthy sensor sits relatively steady around 0.6–0.8 V. Rapid switching, signal stuck at one value, or no signal at all confirms a sensor or wiring issue.
Tools: Scan tool with graphing PIDs
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Verify the bias voltage from the PCM
Disconnect the sensor and key on. The scan tool should still show bias voltage (typically 0.4–0.5 V) at the connector. If not present, the issue is between the connector and the PCM, not the sensor.
Tools: Scan tool, Multimeter
NHTSA complaints & recalls for the 2022 GMC Sierra 1500
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2022 GMC Sierra 1500. Use these to gauge how common a problem is on your specific vehicle before you start chasing GMC Sierra 1500 diagnostics.
- ENGINE 207
- POWER TRAIN 92
- STRUCTURE 90
- ELECTRICAL SYSTEM 75
- UNKNOWN OR OTHER 70
6 active recalls
- EXTERIOR LIGHTING:BRAKE LIGHTS Jun 2022
General Motors (GM) has decided that certain 2022 model year Chevrolet Silverado, and GMC Sierra vehicles equipped with an accessory sport bar. The accessory sport bar contains a high-mounted brake light that may not function. In addition, it may block the vehicle's existing hi…
NHTSA campaign 22V463000 - EXTERIOR LIGHTING:LIGHTING CONTROL MODULE:SOFTWARE Dec 2022
General Motors, LLC (GM) is recalling certain 2020-2023 Cadillac CT4 and CT5; 2021-2023 Buick Envision; and 2022-2023 Cadillac Escalade and Escalade ESV, Chevrolet Silverado 1500, Suburban, Tahoe, GMC Sierra 1500, Yukon, and Yukon XL vehicles. The daytime running lights (DRLs) m…
NHTSA campaign 22V903000 - POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE Oct 2024
General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel engines. The transmission control val…
NHTSA campaign 24V797000 - STRUCTURE:BODY:BUMPERS:ACTIVE SHUTTERS/GRILL Feb 2025
General Motors, LLC (GM) is recalling certain 2022 GMC Sierra 1500 vehicles equipped with chrome front grille deflectors. The attachments that hold the front grille deflectors in place may fracture, resulting in grille detachment.…
NHTSA campaign 25V060000
How do I fix P0136 on a 2022 GMC Sierra 1500?
- Replace the Bank 1 downstream O2 sensor with an OEM part
- Repair damaged downstream sensor wiring
- Clean or replace corroded sensor connector
- Repair upstream exhaust leaks
About the 2020-2024 GMC Sierra 1500
The 2020-2024 GMC Sierra 1500 was commonly sold with the following powertrains: 5.3L V8, 6.2L V8, 2.7L Turbo I4, 3.0L Duramax I6 Diesel. Common trims include Pro, SLE, Elevation, SLT, AT4, Denali.
Why P0136 is the catch-all post-cat code
Each O2 sensor has a family of possible codes:
| Code | Meaning |
|---|---|
| P0136 | Generic circuit issue (catch-all) |
| P0137 | Voltage too low (open or short to ground) |
| P0138 | Voltage too high (short to power or rich condition) |
| P0140 | No activity detected (sensor isn’t reporting anything) |
| P0141 | Heater circuit fault |
When the ECM detects a problem that doesn’t fit the more specific patterns, it falls back to P0136. Reading other codes alongside narrows the diagnosis significantly — P0136 alone is much harder to pin down than P0136 + P0140.
What “downstream sensor” actually monitors
The Bank 1 downstream sensor is mounted in the exhaust after the catalytic converter on Bank 1 (the cylinder bank containing cylinder #1). Its main job is catalyst monitoring — comparing its signal to the upstream sensor’s signal to determine whether the catalyst is still scrubbing exhaust gases.
It provides a secondary, slower fuel-trim correction layer on top of upstream-sensor closed-loop control, but it is not the primary fuel feedback. A bad downstream sensor primarily affects emissions monitoring rather than drivability.
OEM vs aftermarket sensors
The downstream sensor’s role is comparison, not raw measurement, so it is slightly less picky about sensor response curve than the upstream. But aftermarket sensors still produce inconsistent results; for $30 more, an OEM Bosch, Denso, or NTK sensor is worth it on a vehicle you plan to keep.