What to do with a lemon vehicle?

[Summitric]

[h=3]Diagnostic Instructions[/h]

• Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis
• An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

[h=3]DTC Descriptor[/h]DTC P122DIntake Air Flow Valve Position Sensor Exceeded Learning Limit
[h=3]Diagnostic Fault Information[/h]

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Control — Terminal 1	P122C	P02E0	P122C, P122D	P02E4, P02E5
Control — Terminal 2	P122C	P02E0	P122C, P122D	P02E4, P02E5

[h=3]Circuit/System Description[/h]For an overview of the component/system, refer to: Intake Airflow Valve System Description

Circuit	Description
Control — Terminal 1	The output circuit is switched from ground to 12 V to activate the component. The output is PWM controlled.
Control — Terminal 2	The output circuit is switched from ground to 12 V to activate the component. The output is PWM controlled.

Component	Description
K20 Engine Control Module	The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.
Q20 Intake Air Flow Valve	The intake air flow valve of diesel engines reduces the intake air flow rate in part load operation so that a higher exhaust gas recirculation rate can be achieved. The component is actuated by a bidirectional DC motor. Not Activated = Open

[h=3]Conditions for Running the DTC[/h]

• DTC P0071–P0074, P0116–P0119, P02E0–P02E5, P02E8, P02E9, P02EB, P0651, P122B, P122C, P16A0–P16A2 = Not set
• Ambient Air Temperature = Warmer than 49°C (120°F)
• Engine Coolant Temperature = 50 to 150°C (122 to 302°F)
• Ignition Key = Off
• Ignition Voltage = Greater than 10 V
• Intake Air Flow Valve Motor Command = Learning — Complete

Frequency the DTC runs = Continuously — After the running conditions are met
[h=3]Conditions for Setting the DTC[/h]Intake Air Flow Valve Learned Closed Position ≠ 4.3 to 4.6 V
[h=3]Actions Taken When the DTC Sets[/h]DTCs listed in the DTC Descriptor Category = Type A DTC — Additional actions taken:

• Reduced Engine Power = Active
• P16 Instrument Cluster = Reduced Engine Power

[h=3]Conditions for Clearing the DTC[/h]DTCs listed in the DTC Descriptor Category = Type A DTC
[h=3]Diagnostic Aids[/h]

• Certain weather conditions during prolonged trips may cause ice to form in the area of the component: Q20 Intake Air Flow Valve
• If ice is found in the area of the component Q20, clean and dry the component and retest to verify the issue has been corrected.

[h=3]Reference Information[/h]Schematic Reference
Engine Controls Schematics
Connector End View Reference

Master Electrical Component List
Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References
[h=3]Circuit/System Verification[/h]

1. Ignition » On / Vehicle » In Service Mode
2. Verify DTC P02E0–P02E5, P02E8, P02E9, P02EB, P122B, P122C, P16A0–P16A2 is not set.
   
   • If the DTC is set
     Refer to: Diagnostic Trouble Code (DTC) List - Vehicle
   
   
   
   • If the DTC is not set
   
   
3. Clear the DTCs.
4. Ignition Off » For greater than 1 min
5. Ignition » On / Vehicle » In Service Mode
6. Verify DTC P122D is not set.
   
   • If the DTC sets
   
   
   1. Ignition/Vehicle » Off
   2. Verify the following conditions do not exist: Blade @ Q20 Intake Air Flow Valve
      • Warning: Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury.
        
        
      • Binding or Sticking @ Open/Close — Position
      • Closed @ Engine Off
      • Coking / Debris / Dirty / Visible Damage
      • Open/Close — Without spring pressure
      • Water intrusion — Ice
        Refer to: Diagnostic Aids
      
      
      • If a condition exists » Repair or replace as necessary
   
   
   • If the DTC does not set
   
   
7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
   Verify the DTC does not set.
   
   • If the DTC sets
     Repeat step 2
   
   
   
   • If the DTC does not set
   
   
8. All OK.

[h=3]Repair Instructions[/h]Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

• Throttle Body Assembly Replacement — Q20 Intake Air Flow Valve
• For control module replacement, programming, and setup refer to: Control Module References

 

[Summitric]

• Certain weather conditions during prolonged trips may cause ice to form in the area of the component: Q20 Intake Air Flow Valve
• If ice is found in the area of the component Q20, clean and dry the component and retest to verify the issue has been corrected.

THERE IS YOUR MAIN CONCERN AND PROBLEM...

 

[Summitric]

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification

• Throttle Body Assembly Replacement — Q20 Intake Air Flow Valve
• For control module replacement, programming, and setup refer to: Control Module References

THIS MIGHT BE YOUR REPAIR? UNLESS THEY ALREADY REPLACED THE THROTTLE BODY ASS'Y?

 

[ABMax24]

Thanks for that Summitric, I believe moisture/ice is the cause of all my problems. The Intake Valve hasn't been serviced by the dealer yet as both times when the truck was brought in the valve started working again and the code wasn't active anymore, just stored in the memory.

Unfortunately this now takes a back seat to today's problem, on the way home the turbo began making a high pitch whistle again under boost (the turbo is normally silent) the same sound it has the last 2 times it failed. We will be bringing it in to the dealer again tomorrow, if it's diagnosed as another turbo failure we are going to be asking for a buyback of the truck. It's been 700 km since the turbo was changed, didn't even last a full tank of fuel...

 

[snowcannon]

Sounds like your dealer needs to fire a mechanic...

 

[LUCKY 7]

Good luck tomorrow

Thanks for that Summitric, I believe moisture/ice is the cause of all my problems. The Intake Valve hasn't been serviced by the dealer yet as both times when the truck was brought in the valve started working again and the code wasn't active anymore, just stored in the memory.

Unfortunately this now takes a back seat to today's problem, on the way home the turbo began making a high pitch whistle again under boost (the turbo is normally silent) the same sound it has the last 2 times it failed. We will be bringing it in to the dealer again tomorrow, if it's diagnosed as another turbo failure we are going to be asking for a buyback of the truck. It's been 700 km since the turbo was changed, didn't even last a full tank of fuel...

 

[ABMax24]

Sounds like your dealer needs to fire a mechanic...

Actually my dealer is awesome, their customer service is about as good as it gets. It's GM's sh!tty design that is the problem. My dealer can only replace the parts that GM allows them to, when the turbo fails they replace the turbo. They can't go in and delete the PCV system even though it would fix the problem, and I'm sure not going to do it and jeopardize warranty on a vehicle that has been such a lemon.

As far as I'm concerned the engineers on the 2.8 Duramax design team deserve the blame for these failures.

 

[AreWeThereYet]

Actually my dealer is awesome, their customer service is about as good as it gets. It's GM's sh!tty design that is the problem. My dealer can only replace the parts that GM allows them to, when the turbo fails they replace the turbo. They can't go in and delete the PCV system even though it would fix the problem, and I'm sure not going to do it and jeopardize warranty on a vehicle that has been such a lemon.

As far as I'm concerned the engineers on the 2.8 Duramax design team deserve the blame for these failures.

I was looking at one of those mid size trucks last year,.. kind of glad I passed on it,.. good luck bud on your visit.

 

[ABMax24]

I was looking at one of those mid size trucks last year,.. kind of glad I passed on it,.. good luck bud on your visit.

I was skeptical when we first bought it too, DEF issues seemed to be the most common problem, but all the parts had been updated for 2018 and seemed to be working well so we took the gamble and lost.

 

[tex78]

Actually my dealer is awesome, their customer service is about as good as it gets. It's GM's sh!tty design that is the problem. My dealer can only replace the parts that GM allows them to, when the turbo fails they replace the turbo. They can't go in and delete the PCV system even though it would fix the problem, and I'm sure not going to do it and jeopardize warranty on a vehicle that has been such a lemon.

As far as I'm concerned the engineers on the 2.8 Duramax design team deserve the blame for these failures.

Lmfao, never done a turbo either



Like I said,, a few particulate matter sensors is all I have done

Have had and seen lots of ebcm connectors full of water and corroded pins, usually sets a code for lh front abs sensor issue

 

[ABMax24]

Lmfao, never done a turbo either



Like I said,, a few particulate matter sensors is all I have done

Have had and seen lots of ebcm connectors full of water and corroded pins, usually sets a code for lh front abs sensor issue

I don't know what to say, the local GMC dealer claims they haven't changed any either, but when we did the first turbo last April we were the second turbo failure at the local Chevy dealer, I'll try to remember to ask tomorrow how many they have done since.

 

[ABMax24]

Dropped the truck off to dealer today, too late to look at it today, should have a diagnosis tomorrow.

Opened a claim with GM Canada, sounds like we won't know anything on that until Tuesday.

 

[tex78]

Dropped the truck off to dealer today, too late to look at it today, should have a diagnosis tomorrow.

Opened a claim with GM Canada, sounds like we won't know anything on that until Tuesday.

Had two in today for more particulate matter sensors lol

 

[Summitric]

Had two in today for more particulate matter sensors lol

I think I remember seeing a tech bulletin &/or discussion somewhere that suggested poor quality Diesel fuel was causing the sensor failures... It did say Esso, Petro-can and Shell were the recomended fuels, as they all have enough cleaners etc in the fuel along with the proper winter/summer anti-waxing capabilities ??? Have you heard anything on this?

 

[ABMax24]

Had two in today for more particulate matter sensors lol

So far no issue with those, but probably not enough miles on it for them to go.

 

[ABMax24]

I think I remember seeing a tech bulletin &/or discussion somewhere that suggested poor quality Diesel fuel was causing the sensor failures... It did say Esso, Petro-can and Shell were the recomended fuels, as they all have enough cleaners etc in the fuel along with the proper winter/summer anti-waxing capabilities ??? Have you heard anything on this?

We burn Costco fuel because it's cheap, and the fact that it's always fresh. I'd really like to know how many B-train loads our Costco station pumps everyday.

 

[Rene G]

We burn Costco fuel because it's cheap, and the fact that it's always fresh. I'd really like to know how many B-train loads our Costco station pumps everyday.

They go through a lot, they also run too tier fuels.

 

[tex78]

So far no issue with those, but probably not enough miles on it for them to go.

Had a few, less than 5000 km

 

[tex78]

I think I remember seeing a tech bulletin &/or discussion somewhere that suggested poor quality Diesel fuel was causing the sensor failures... It did say Esso, Petro-can and Shell were the recomended fuels, as they all have enough cleaners etc in the fuel along with the proper winter/summer anti-waxing capabilities ??? Have you heard anything on this?

G. M has allways said to use top tier fuels, even gas engines for carbon build up on valves from direct injection

 

[ABMax24]

Had a few, less than 5000 km

Brutal.

GM has also decided to sell the plant that builds these engines to a Chinese company. I wonder if this will be the end of the 2.8?

https://gmauthority.com/blog/2020/0...iland-sell-rayong-plant-to-great-wall-motors/