It depends on what part it needs.. You need to have it diagnosed and then see if the parts needed are covered by GM or Allied.

 

So you’re saying that at least some parts of the def system are considered power train?

 

It depends on what part is failing.. There's a list of things that are covered by powertrain warranty.. Then there's a list that is covered by emissions warranty..
Find out what you need then see what it is listed under..
Can only guess otherwise.

 

Emissions system warranty is 5 yr 50,000 miles. DEF is emissions sys.
Fed rule.

 

I thought I read on here before that the Emissions Warranty was 150k miles...? My dealership replaced my DEF heater and injectors at no charge with 70k miles on it.

 

sounds like a short to power in the harness more then a mechanic issue. we have a ton of class 8 trucks at the shop that we find wire harness rubbed and wires damaged

 

Possible extensions by GM for known issues?

Looking through my owners manual, it's a little cloudy. But 5 years is constant and either 50 or 100,000 miles depending on what it is. Your injectors may have been considered powertrain not emissions. DEF heater....I can see that being covered...or not. Your dealer did right for you, so that's awesome.

 

5yr/100k is the federal standard.

 

I have a 3500 2021 AT4 that's been in the shop since Jan 2022 waiting for the deff system to be fixed. They have 0 parts. GMC should be responsible for making my truck payments while it continues to sit on their lot. I'm definitely looking at legal counsel. I called last week I'm 3rd in line so he said maybe another 3 months! I call BS! Can't wait to get it done I'm trading it in and walking away from GM for good.

 

I know of a few Dodge and Ford guys with DEF long term problems as well. Wonder if their parts ( or lack of) are the same as ours?

 

Yes. and Yes Ford and Dodge has their own issues.

 

The owners manual states the transmission module is part of the emission system…

nope.

there are other issues “not covered”.

So, boils down to the dealer…

 

I had a 13 2500hd and the Trans model went out at like 45k and they said it was covered under emissions warranty but my def heater at 60k wasn't but then it was but then it wasn't but then it was lol in the long run just keep asking questions and doing research it is all covered for so long and it's all junk

 

The computer controls/commands the alternator output -- so voltage variation is very common and not necessarily an indication of electrical problem.

They have recently released info suggesting the DEF heater problem source has been identified and that a new supplier is suppling the part now. (perhaps this re-tool and part mod is part of the reason the tank supply/availability has been so low?)


From

DEF Tank Heater and Wiring Harness Updates – TechLink

gm-techlink.com

DEF Tank Heater and Wiring Harness Updates
June 21, 2022
Several updates are now available to address Diesel Exhaust Fluid (DEF) tank, or Emission Reduction Fluid tank (Fig. 18), conditions on some full-size trucks and SUVs equipped with the 6.6L Duramax diesel engine (RPO L5P) or 3.0L Duramax diesel engine (RPO LM2).

Fig. 18
DEF Tank Heater
The DEF tank heater may be faulty on some 2020-2021 Silverado 1500, Silverado 2500HD/3500HD, Sierra 1500, Sierra 2500HD/3500HD; and 2021 Tahoe, Suburban, Yukon and Escalade models equipped with the 6.6L Duramax diesel engine or 3.0L Duramax diesel engine. If the DEF tank heater is not operating properly, there may be a Service Emission System/Service Exhaust Fluid System message on the Driver Information Center along with an illuminated Check Engine MIL. DTCs P20BB (Reductant Heater 1 Control Circuit Low Voltage) and P20C3 (Reductant Heater 3 Control Circuit Low Voltage Test Status) also may be set in the Engine Control Module (ECM).
A new calibration for the DEF controller is available that will reduce the possibility that DTCs P20BB and P20C3 will set. Refer to Bulletin #22-NA-112.
The faulty DEF tank heater may be caused by the tank heating elements being exposed to DEF and shorting to the pump ground. Shown is an example of a heater that would set a code if it was in a tank and exposed to DEF. (Fig. 19) GM now has a different supplier making the heater mats for both production and service DEF tanks.

Fig. 19
To determine if there is a short to ground, measure resistance at the Emission Reductant Fluid Supply Pump Module, which would indicate that the heater has been exposed to DEF. The reductant control module is mounted outside the tank. (Fig. 20)

Fig. 20
TIP: Be sure that the DEF tank is at least half full of DEF before performing the resistance measurement.
With the Emission Reduction Fluid Tank wiring harness disconnected, measure resistance from pin 9 (Fig. 21, #1) to pin 14 (Fig. 21, #3) using a Digital Multimeter and probe adapter J-35616-17 Light Green. Next, measure resistance from pin 10 (Fig. 21, #2) to pin 14. (Fig. 21, #3)

Fig. 21
If either resistance reading is less than 10M ohm, the heater is faulty and the DEF tank should be replaced. If both resistance readings are greater than 10M ohm, continue with diagnostics according to the appropriate Service Information.
For more information, refer to Bulletin #21-NA-002.
Electrical Connector and Wiring Harness
If one or more of the following DTCs – P20C1, P21DD, P221C, P10D9, P10F3, P143C, P20B9, and/or P221E – are set in the ECM on 2020-2021 Silverado 1500, Silverado 2500HD/3500HD, Sierra 1500, Sierra 2500HD/3500HD; and 2021 Tahoe, Suburban, Yukon and Escalade models equipped with the 6.6L Duramax diesel engine or 3.0L Duramax diesel engine, check for damage to the electrical connector at the DEF pump assembly and the DEF tank harness. (Fig. 22)

Fig. 22
If there is a poor connection condition, reprogram the DEF controller with the updated calibration that is available, which will lower the amperage to the DEF tank heater. Repair or replace the electrical connector as needed.
For more information, refer to Bulletin #21-NA-006.
On some 2020-2022 Silverado 2500HD/3500HD and Sierra 2500HD/3500HD trucks equipped with the 6.6L Duramax diesel engine, DTCs P20B9 (Reductant Heater 1 Control Circuit) and P20C1 (Reductant Heater 3 Control Circuit) may set after the DEF tank is replaced. These DTCs may be caused by a wiring change to the service DEF tanks. (Fig. 23)

Fig. 23
Prior to ordering any parts, check the 16-pin wiring harness connector to verify which wiring harness is installed on the vehicle. On the first-design DEF tank harness (A38 Reductant Pump/Sender Assembly 16-way connector), pin location 12 will be empty. On the second-design DEF tank harness, pin location 12 has a wire in the connector.
The connectors on 2020 through early build 2022 models were originally built with cavities 6, 12 and 13 unoccupied. On late build 2022 models, terminal 10 was moved to cavity 12 (Fig. 24) and terminal 11 was moved to cavity 6. All DEF tanks, including tanks for servicing 2020 through early build 2022 models, are configured this same way. If replacing the DEF tank on an early build model, the service DEF tank will come with the correct harness installed.

Fig. 24
For complete wiring pinout charts for the first-design harness and second-design harness, refer to #PIP5838B.
Also refer to the charts in the #PIP5838B, or use the 2022 late build schematics and connector end views in the appropriate Service Information, when performing diagnostics on an early build model with an updated DEF tank installed.
Early build harnesses also are still available to service a damaged harness on vehicles with the original DEF tank. Verify the correct wiring harness on the vehicle before ordering any parts.