GM service update N212342980, released January 2022, says the DEF tank connector on certain 2020 and 2021 Chevrolet Silverado 2500HD trucks with the 6.6-liter diesel, RPO L5P, may overheat and set codes P10D9, P143C, and P10F3, which reduces engine speed. The same update names 2020 and 2021 Silverado 3500HD and GMC Sierra 2500HD and 3500HD trucks with that engine. A dealer message dated January 20, 2022, says the U.S. vehicles involved are approximately 38,000. That count is GM's. Dealers reprogram the reductant control module. The update says no parts are required, and that the VIN has to show Open before the work starts. NHTSA complaint ODI 11717625, on a 2020 Silverado 2500, says that at 50 mph the truck went into limp mode with the check-engine light on and the messages Service Emission System, See Owner's Manual, and 65 MPH Max Speed. The dealer said the diesel exhaust fluid tank connector terminal had overheated and that the tank and the wiring harness needed to be replaced. The truck was not repaired because of the cost. The owner associated the failure with N212342980. The mileage is 173,794. Complaint ODI 11717543, on a 2020 Silverado 2500HD with the 6.6 Duramax, says code P20B9, Reductant Heater A Control Circuit/Open, was set on about January 24, 2026. A dealer on January 27, 2026, wrote that the DEF tank should be replaced, that the heater circuit was commanded on and drew zero amps, and that the pump-module terminals were burned. P20B9 is not one of the three codes in the service update. Complaint ODI 11456577 says a DEF tank heater short melted a wiring harness and put the truck in limp mode. The owner wrote that the part was on a 6-month backorder and that GM made no reparations. Complaint ODI 11635680, on a 2021 Silverado 2500, says code P10D9 was set and the electrical harness to the DEF tank melted. The owner calls N212342980 a recall, says the truck was not part of it, and says the count is larger than 38,000. Those words and that count are the owner's. The owner wrote that Chevrolet customer service said the melted harness is not covered, and that a technician at Milnes Chevy in Imlay City sees the same melted harness on trucks that are not in the program. Complaint ODI 11646462 says a DEF failure put the truck in limp mode at 65 mph, then 55 mph, then 5 mph, and that the DEF heater went bad. Complaint ODI 11704659 says a connector for the heater system was involved, that a certified mechanic diagnosed code P20C1, reductant heater failure, and that the truck was not repaired. The mileage is about 68,000. P20C1 is not in the service update's code list. One sentence in that filing is hard to follow, so this page does not treat it as a finding. These filings do not show an overheated connector on every 2020 or 2021 Silverado 2500.

The service update says the DEF tank connector may overheat and set P10D9, P143C, and P10F3, and that the correction is a reductant-control-module reprogram with no parts. The complaints describe burned or melted terminals, a melted harness, and a tank or harness replacement. That is a different repair than the reprogram. Two complaints name P20B9 and P20C1, which are not the codes in the update. The filings do not include a measured reason the terminals overheated. The update does not say every DEF complaint on these model years is this connector.

If the truck limits speed and shows a service emission or DEF message, get off the road when you can. Limp mode is what these complaints describe, including while an owner was concerned about towing. Do not treat a speed limit as a way to finish a highway tow. The service update tells a dealer to reprogram the reductant control module when the VIN shows Open. It lists 0.2 hour under labor operation 9105960 if the module is already at that software, and 0.3 hour under 9105961 for the reprogramming. Ask the dealer to look up N212342980 for the VIN. The complaints describe a burned connector and a tank or harness that had to be replaced. Ask the dealer which repair they are quoting, the reprogram or the tank and harness, before you approve work. A reprogram does not, by itself, replace burned terminals. Sourced public report. This is not a repair procedure from RigFix.

Not a driveway job in these sources. The service update is written for a dealer. The complaints describe dealer diagnosis. There is no published procedure here.

The service update says no parts are required for the reprogram. The complaints describe a DEF tank, a wiring harness, and burned connector terminals. They do not give a part number.

This is not a recall. N212342980 is a service update. It expires at the end of the involved truck's new-vehicle limited warranty, and the VIN has to show Open before the work starts. An owner who calls it a recall is describing the document in their own words. The complaints do not all say who paid. One owner wrote that customer service said a melted harness is not covered. A complaint is not a coverage decision, a failure rate, or a diagnosis for another Silverado 2500. The years on this page are 2020 and 2021, which are the years the update and these complaints name. The same update names the 2020 and 2021 Sierra 2500, which has its own page, and the Silverado 3500 and Sierra 3500. A 2020 Sierra 3500 complaint, ODI 11648405, names N212342980 on that model and says the connector still failed after the update. That filing is not this model. The 2024 valve-body report on this model is a different page. Recall 24V-797 is a different campaign, for certain 2020 through 2022 diesel transmission valves.

Last updated October 15, 2026

2020 Chevrolet Silverado 2500

Silverado 2500 DEF tank connector overheats on 2020 and 2021 trucks

Owner reportEngine

Symptoms: GM service update N212342980, released January 2022, says the DEF tank connector on certain 2020 and 2021 Chevrolet Silverado 2500HD trucks with the 6.6-liter diesel, RPO L5P, may overheat and set codes P10D9, P143C, and P10F3, which reduces engine speed. The same update names 2020 and 2021 Silverado 3500HD and GMC Sierra 2500HD and 3500HD trucks with that engine. A dealer message dated January 20, 2022, says the U.S. vehicles involved are approximately 38,000. That count is GM's. Dealers reprogram the reductant control module. The update says no parts are required, and that the VIN has to show Open before the work starts. NHTSA complaint ODI 11717625, on a 2020 Silverado 2500, says that at 50 mph the truck went into limp mode with the check-engine light on and the messages Service Emission System, See Owner's Manual, and 65 MPH Max Speed. The dealer said the diesel exhaust fluid tank connector terminal had overheated and that the tank and the wiring harness needed to be replaced. The truck was not repaired because of the cost. The owner associated the failure with N212342980. The mileage is 173,794. Complaint ODI 11717543, on a 2020 Silverado 2500HD with the 6.6 Duramax, says code P20B9, Reductant Heater A Control Circuit/Open, was set on about January 24, 2026. A dealer on January 27, 2026, wrote that the DEF tank should be replaced, that the heater circuit was commanded on and drew zero amps, and that the pump-module terminals were burned. P20B9 is not one of the three codes in the service update. Complaint ODI 11456577 says a DEF tank heater short melted a wiring harness and put the truck in limp mode. The owner wrote that the part was on a 6-month backorder and that GM made no reparations. Complaint ODI 11635680, on a 2021 Silverado 2500, says code P10D9 was set and the electrical harness to the DEF tank melted. The owner calls N212342980 a recall, says the truck was not part of it, and says the count is larger than 38,000. Those words and that count are the owner's. The owner wrote that Chevrolet customer service said the melted harness is not covered, and that a technician at Milnes Chevy in Imlay City sees the same melted harness on trucks that are not in the program. Complaint ODI 11646462 says a DEF failure put the truck in limp mode at 65 mph, then 55 mph, then 5 mph, and that the DEF heater went bad. Complaint ODI 11704659 says a connector for the heater system was involved, that a certified mechanic diagnosed code P20C1, reductant heater failure, and that the truck was not repaired. The mileage is about 68,000. P20C1 is not in the service update's code list. One sentence in that filing is hard to follow, so this page does not treat it as a finding. These filings do not show an overheated connector on every 2020 or 2021 Silverado 2500.
Likely causes: The service update says the DEF tank connector may overheat and set P10D9, P143C, and P10F3, and that the correction is a reductant-control-module reprogram with no parts. The complaints describe burned or melted terminals, a melted harness, and a tank or harness replacement. That is a different repair than the reprogram. Two complaints name P20B9 and P20C1, which are not the codes in the update. The filings do not include a measured reason the terminals overheated. The update does not say every DEF complaint on these model years is this connector.
Common fixes: If the truck limits speed and shows a service emission or DEF message, get off the road when you can. Limp mode is what these complaints describe, including while an owner was concerned about towing. Do not treat a speed limit as a way to finish a highway tow. The service update tells a dealer to reprogram the reductant control module when the VIN shows Open. It lists 0.2 hour under labor operation 9105960 if the module is already at that software, and 0.3 hour under 9105961 for the reprogramming. Ask the dealer to look up N212342980 for the VIN. The complaints describe a burned connector and a tank or harness that had to be replaced. Ask the dealer which repair they are quoting, the reprogram or the tank and harness, before you approve work. A reprogram does not, by itself, replace burned terminals.
DIY difficulty: Not a driveway job in these sources. The service update is written for a dealer. The complaints describe dealer diagnosis. There is no published procedure here.
Parts needed: The service update says no parts are required for the reprogram. The complaints describe a DEF tank, a wiring harness, and burned connector terminals. They do not give a part number.
Warranty notes: This is not a recall. N212342980 is a service update. It expires at the end of the involved truck's new-vehicle limited warranty, and the VIN has to show Open before the work starts. An owner who calls it a recall is describing the document in their own words. The complaints do not all say who paid. One owner wrote that customer service said a melted harness is not covered. A complaint is not a coverage decision, a failure rate, or a diagnosis for another Silverado 2500. The years on this page are 2020 and 2021, which are the years the update and these complaints name. The same update names the 2020 and 2021 Sierra 2500, which has its own page, and the Silverado 3500 and Sierra 3500. A 2020 Sierra 3500 complaint, ODI 11648405, names N212342980 on that model and says the connector still failed after the update. That filing is not this model. The 2024 valve-body report on this model is a different page. Recall 24V-797 is a different campaign, for certain 2020 through 2022 diesel transmission valves.

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Silverado 2500 DEF tank connector overheats on 2020 and 2021 trucks

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