This document should be used in conjunction with the AQ3CO Characterization Note and the Product Safety Datasheet (PSDS 15).
The data provided in this document is based on the assumption that the sensor is used at 20°C, 50% rH, and 1013 mBar for three months from the date of sensor manufacture. For guidance on sensor performance outside of these limits, please refer to the AQ3CO Characterization Note.
The output signal can drift below the lower limit over time. For guidance on the safe use of the sensor, please refer to the Characterization Note. Sensor Part Number (without board): ABQ045-H00
Module Part Number (with board): QAB045-H00
PCBA Part Number: AQ3-BP01



AQ3CO Carbon Monoxide Gas Sensor Technical Specifications


Technology4-electrode electrochemical
Measurement Range 0 ppm CO to 10 ppm CO
Maximum Overloadwithout board: 50 ppm CO
with the board: 30 ppm CO
Onboard Filterto remove SOx/NOx and H2
Sensitivity*without board:
240 nA/ppm ±80 nA/ppm
with board:
90 mV/ppm ±35 mV/ppm
Response Time (T)< 70 seconds
Resolution*20 ppb when used with recommended
Baseline Offset*without board: -200 nA ~ 360 nA
with board: -80 mV ~ 140 mV
Repeatability*< ±3% of signal
Low Detection Limit* 40 ppb
Recommended Load
68 Ω
Sensor Bias Voltageno bias (without board)
Power Supply Required5 Vdc (with board)
Power Consumption370 mA @ 5 Vdc (with board)
Weightwithout board: < 22 g
with board: < 30 g
Outer Plastic Body
Sealing Gasket
Contact Materialmild steel with gold flash-over nickel plate
Orientation Sensitivitynone
Temperature Range
-30°C to 50°C
Storage Temperature
0°C to 20°C in an original sealed container
Operating Humidity
15% RH to 90% rH
Operating Pressure
atmospheric ±10%
Typical Applicationsambient environmental monitoring
Storage Life6 months in original sealed container
Long-Term Sensitivity
< 10% signal loss per annum
Expected Oper. Lifetwo years in air
Warrantyone year

*Specifications are valid at 20°C, 50% RH, and 1013 mbar using AQ3 low noise board. Performance characteristics outline the performance of sensors supplied within the first 3 months. The output signal can drift below the lower limit over time. Please be aware that sensors’ performance is also reflected by circuit board design.
** Linear through the concentration range across the whole operational environment range.

All tolerances ±0,15 mm unless otherwise stated

Product Dimensions

Dimensions mm.

Honeywell AQ3CO SENSOR Carbon Monoxide (CO) Gas Sensor -

All tolerances ±0,15 mm unless otherwise stated

Honeywell AQ3CO SENSOR Carbon Monoxide (CO) Gas Sensor -Sensor with board

Pin Definition

(4.8 V ~ 5.5 V)

Filter Information

Removes acid gases such as SOx/NOx and H2 S


Gas sensors are designed for operation in a wide range of environments and harsh conditions. However, it is important that exposure to high concentrations of solvent vapors is avoided, during storage, fitting into instruments, and operation. When using sensors with printed circuit boards (PCBs), degreasing agents should be used before the sensor is fitted.
Do not glue directly on or near the sensor as the solvent may cause crazing of the plastic.

Cross Sensitivity Table

Whilst AQ3 Series gas sensors are designed to be highly specific to the gas they are intended to measure, they will still respond to some degree to various other gases.
The table below is not exclusive and other gases not included in the table may still cause a sensor to react.
IMPORTANT NOTE: The cross-sensitivity data shown below does not form part of the product specification and is supplied for guidance only. Values quoted are based on tests conducted on a small number of sensors and any batch may show significant variation. For the most accurate measurements, an instrument should be calibrated using the gas under investigation.

GasGas ConcentrationCross Interference
Sulfur Dioxide (SO2)5 ppm0%<x%<7%
Nitrogen Dioxide (NO2 )5 ppm-3%<x%<5%
Ozone (O)1 ppm-7%<x%<4%
Isobutylene (C4 H8 )1 ppm~None


Honeywell warrants goods of its manufacture as being free of defective materials and faulty workmanship during the applicable warranty period. Honeywell’s standard product warranty applies unless agreed to otherwise by Honeywell in writing; please refer to your order acknowledgment or consult your local sales office for specific warranty details. If warranted goods are returned to Honeywell during the period of coverage, Honeywell will repair or replace, at its option, without charge those items that Honeywell, in its sole discretion, finds defective. The foregoing is the buyer’s sole remedy and is in lieu of all other warranties, expressed or implied, including those of merchantability and fitness for a particular purpose. In no event shall Honeywell be liable for consequential, special, or indirect damages.
While Honeywell may provide application assistance personally, through our literature and the Honeywell website, it is the buyer’s sole responsibility to determine the suitability of the product in the application. Specifications may change without notice.
The information we supply is believed to be accurate and reliable as of this writing.
However, Honeywell assumes no responsibility for its use.

Honeywell AQ3CO SENSOR Carbon Monoxide (CO) Gas Sensor -WARINING WARNING

  • The information presented in this product sheet is for reference only.
    Do not use this document as a product installation guide.
  • Complete installation, operation, and maintenance information is provided in the instructions supplied with each product.

Failure to comply with these instructions could result in death or serious injury.

This sensor is designed to be used in environmental applications. To ensure that the sensor and/or instrument in which it is used, are operating properly, it is a requirement that the function of the device is confirmed by exposure to target gas (bump check) before each
use of the sensor and/or instrument.
Failure to carry out such tests may jeopardize the safety of people and Property.


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Honeywell Advanced Sensing
Technologies service its customers through a worldwide network of sales offices and distributors. For application assistance, current specifications, pricing or the nearest Authorized Distributor, visit our website or call:
USA/Canada +1 302 613 4491
Latin America +1 305 805 8188
Europe +44 1344 238258
Japan +81 (0) 3-6730-7152
Singapore +65 6355 2828
Greater China +86 4006396841

Advanced Sensing Technologies
830 East Arapaho Road
Richardson, TX 75081

AQ3CO Datasheet ECN 5062 | 002722-1-EN | 1 | 05/21
© 2021 Honeywell International Inc.

Documents / Resources

Honeywell AQ3CO SENSOR Carbon Monoxide (CO) Gas Sensor [pdf] User Guide
AQ3CO SENSOR, Carbon Monoxide CO Gas Sensor


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