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Discussion Starter · #1 ·
Hello... I just bought an 08 2500hd 4x4 and I think I may have been had. 167k miles. exhaust has been done, lift, tires, and from what I was told a 250 hp tune from the owner previous to the one I bought it from. Here's the issue described the best way that I can. Under moderate to heavy acceleration it feels like someone is flicking the power on and off. I can watch the rpms drop by 300-400 before picking back up. Fast like though on off on off on off on off on off on off. Changed the fuel filter oil is still ok. Only code that pulls is p02e8
 

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Discussion Starter · #2 ·
Bump
 

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Hello... I just bought an 08 2500hd 4x4 and I think I may have been had. 167k miles. exhaust has been done, lift, tires, and from what I was told a 250 hp tune from the owner previous to the one I bought it from. Here's the issue described the best way that I can. Under moderate to heavy acceleration it feels like someone is flicking the power on and off. I can watch the rpms drop by 300-400 before picking back up. Fast like though on off on off on off on off on off on off. Changed the fuel filter oil is still ok. Only code that pulls is p02e8
Im not sure about the code, but what I can tell you is if you keep driving it like you stole it, without knowing what tune is in it, or with anything over about a 100HP tune, you are asking to limp your transmission.

That will be a $4,000-$5,000 mistake.

One more piece of advice, it is a holiday, people are busy. Don't get impatient waiting for an answer to your questions.

Use the time to do searches on here and read about the issues are having
 

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Discussion Starter · #4 ·
It has a 5 setting dial in which I have it on the lowest setting. No worries, I'm reading every thing I can until it gets figures out
 

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You're throwing an emissions related intake code.
 

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DTC P02E8 or P02E9

Diagnostic Instructions



  • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. See: Testing and Inspection\Initial Inspection and Diagnostic Overview
  • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  • Diagnostic Procedure Instructions provide an overview of each diagnostic category.
DTC Descriptors

DTC P02E8


  • Diesel Intake Air (IA) Flow Position Sensor Circuit Low Voltage
DTC P02E9


  • Diesel Intake Air (IA) Flow Position Sensor Circuit High Voltage
Diagnostic Fault Information







Circuit/System Description

The intake air (IA) valve is a normally open valve and is only operated during a DPF regeneration. The position of the IA valve is controlled by the engine control module (ECM). The IAF Valve system uses a position sensor located within the valve assembly to monitor the position of the valve. The position sensor has the following circuits:


  • 5-volt reference circuit
  • Low reference circuit
  • Signal circuit
The IAF valve uses a motor to move the valve to a closed position and spring tension returns it to the open position. The motor has the following circuits:



  • Motor control 1 circuit
  • Motor control 2 circuit
Conditions for Running the DTC

P02E8 and P02E9


  • DTCs P0698 or P0699 are not set.
  • The ignition is ON.
  • DTCs P02E8 and P02E9 run continuously.
Conditions for Setting the DTC

P02E8

The IAF valve position is less than 0.102 volt for 3 seconds.

P02E9

The IAF valve position is greater than 4.75 volts for 3 seconds.

Action Taken When the DTC Sets

DTCs P02E8 and P02E9 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P02E8 and P02E9 are Type A DTCs.

Circuit/System Verification



  1. Command the IA valve from 100 percent to 0 percent. The IAF Valve Commanded Position and the IAF Valve Position parameter should match.
  2. After the engine has been running, turn OFF the ignition. Observe the IA Valve Position parameter fluctuates between 100 percent and 0 percent several times.
  3. 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.
Circuit/System Testing



  1. Ignition OFF, disconnect the harness connector at the IA valve. Allow up to 2 minutes for the ECM to completely power down.
  2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal C and ground.

    • If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

  1. Ignition ON, test for 4.8-5.2 volts between 5-volt reference circuit terminal F and ground.

    • If less than 4.8 volts, test 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
    • If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

  1. Verify the scan tool IAF valve position sensor voltage is less than 0.1 volt.

    • If greater than 0.1 volt, test the signal circuit terminal E for a short to voltage. If the circuit tests normal, replace the ECM.

  1. Install a 3A fused jumper wire between the signal circuit terminal E and the 5-volt reference circuit terminal F of the IA valve harness connector. Verify that the scan tool IAF position sensor voltage is more than 4.8 volts.

    • If less than 4.8 volts, test the IA valve signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

  1. If all circuits test normal, replace the IA valve.
 

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Discussion Starter · #7 ·
Ok, (if the sensor was indeed bad or what ever the cause of the dtc) Would this issue cause what I have described?
 

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You may or may not be running tunes....on a not known modded exhaust (delete DPF?) or what's been done in the tuning to disable emissions....and this code in the mix.
What's been disabled, what hasn't? Is it the valve, the sensors, the wiring to 'em, etc.?
 

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It has a 5 setting dial in which I have it on the lowest setting. No worries, I'm reading every thing I can until it gets figures out
There's a good chance your #1 might be something like a valet setting, where the engine doesn't want to run very good, a lot of guys have #1 as valet.
Have you tried #2-#3.
Me personally I would never switch hp on the fly, to risky making bad judgements at the wrong time.
I'm a believer of finding a single mild tune and leave it there, my heavy tow is 30-40 hp.

Did you get the AutoCal device with your truck ?
If you did then you might be able to track down what tunes you have, with the serial # on the back and/or tuners label on the front.

Example of tunes on one tuners website.
2006 – 2010 LBZ – LMM Duramax RWHP Levels over factory rated HP for Stock Transmissions applications:
30 HP – Optimized Stock/Eco
60 HP – Heavy Tow
100 HP – Light Tow
120 HP – Street
150 HP – Race (LBZ & LMM Only)
2001 – 2010 (LB7, LLY, LBZ, LMM) Duramax RWHP Levels over factory rated HP for Built Transmissions applications:
30 HP – Optimized Stock/Eco
60 HP – Heavy Tow
100 HP – Light Tow
160 HP – Street
230 HP – Race

Above is off one of the tuners website, another EFI tuner offers 250 hp race, very few people getting tunes like/similar to above pay attention to what's underlined above.
One of 2 reasons is the person taking the order will say it's no big deal, if your easy you shouldn't have any issues, you don't need a stink'n built trans.
#2, I don't know of any human being that would not get that heavy lead foot syndrome on that skinny pedal especially if they've been :beer or smookin or both.
Or
When that Twin Turbo Telsa pulls up along side of you.
 
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