Diagnostic Tip – Diesel Exhaust Fluid System Contamination – 2010-2023 Chevrolet & GMC

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Copyright 2022 General Motors LLC. All Rights Reserved. Service Bulletin Bulletin No.: 19-NA-237 Date: September, 2022 INFORMATION Subject: Diagnostic Tip – Diesel Exhaust Fluid System Contamination This bulletin replaces PIP5370D. Please discard PIP5370D. Brand: Model: Model Year: VIN: Engine: Transmission: from to from to Cadillac Escalade Models 2021 2023 LM2 Chevrolet Cruze 2014 2015 LUZ 2017 2019 LH7 Colorado 2016 2022 LWN Equinox 2018 2019 LH7 Express 2010 2016 LGH 2017 2022 LWN Silverado 2011 2016 LML 2017 2018 L5P Silverado 1500 2020 2021 LM2 Silverado 1500 LTD (RPO J21, VIN Digit 5 = W / Y) 2022 2022 Silverado 1500 New (RPO J22, VIN Digit 5 = A / D) Silverado 1500 2023 2023 LZ0 Silverado 2500/3500 2019 2023 L5P Silverado 4500HD, 5500HD and 6500HD 2019 2023 L5D Suburban 2021 2023 LM2 Tahoe 2021 2023 LM2 GMC Savana 2010 2016 LGH 2017 2022 LWN Sierra 2011 2016 LML, LGH 2017 2018 L5P Sierra 1500 2020 2021 LM2 Sierra 1500 Limited (RPO J21, VIN Digit 5 = 8 / 9) 2022 2022 Sierra 1500 New (RPO J22, VIN Digit 5 = H / U) Sierra 1500 2023 2023 LZ0 Sierra 2500/3500 2019 2023 L5P Yukon Models 2021 2023 LM2 Page 2 September, 2022 Bulletin No.: 19-NA-237 Involved Region or Country North America Condition Some customers may comment on one or more of the following conditions: • Exhaust fluid quality poor message on the Driver Information Center (DIC). • Diesel exhaust fluid warning lamp on. • Other exhaust fluid quality related concerns. Cause This condition may be caused by contamination in the diesel exhaust fluid (DEF) system and it’s components. Correction Note: Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. Refer to SI for Contaminants in Diesel Exhaust Fluid Diagnosis and use special tools J26568 Coolant and Battery Fluid Tester or EN50422 Diesel Exhaust Fluid Refractometer for fluid testing. Note: All 2017 and newer model year diesel vehicles, with the exception of the Colorado and Canyon, are equipped with a DEF quality sensor integrated into the DEF tank. The value of this sensor can be read with the scan tool in the reductant data as the Reductant Concentration. Information Important: Service agents must comply with all International, Federal, State, Provincial, and/or Local laws applicable to the activities it performs under this bulletin, including but not limited to handling, deploying, preparing, classifying, packaging, marking, labeling, and shipping dangerous goods. In the event of a conflict between the procedures set forth in this bulletin and the laws that apply to your dealership, you must follow those applicable laws. Below are examples of DEF mixed with different sources of contamination. 4373640 Diesel Exhaust Fluid (DEF) mixed with Brake Fluid. 4373641 Diesel Exhaust Fluid (DEF) mixed with Dexcool. Bulletin No.: 19-NA-237 September, 2022 Page 3 4373642 Diesel Exhaust Fluid (DEF) mixed with Diesel Fuel. 4373644 Diesel Exhaust Fluid (DEF) mixed with Engine Oil. 4373645 Diesel Exhaust Fluid (DEF) mixed with Power Steering Fluid. 4373646 Diesel Exhaust Fluid (DEF) mixed with Transmission Fluid. Page 4 September, 2022 Bulletin No.: 19-NA-237 4373647 Diesel Exhaust Fluid (DEF) mixed with Windshield Washer Fluid. 4373648 Diesel Exhaust Fluid (DEF) mixed with Water. Warranty Information This bulletin is being published to help technicians identify signs of contamination in Diesel Exhaust Fluid (DEF). If you see evidence of contamination take appropriate measures to ensure that all of the contaminated fluid is removed from the vehicle. Any components that have failed as a result of contamination should NOT be covered by warranty. Version 4 Modified Released October 17, 2019 Revised October 27, 2020 – Added 2021 Model Year. Revised January 10, 2022 – Added 2022 Model Year. Revised September 12, 2022 – Added 2023 Model Year and Important statement under Information. GM bulletins are intended for use by professional technicians, NOT a “do-it-yourselfer”. They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

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