2009 Duramax reduce power mode ( update with scan code)

I had same low power issue with mine turned out to be water in the fuel filter.

Yes. That’s why I did the delete and exhaust.

Now it says “engine overheated reduced power”

This is after it’s sat a while, and had a tune

Could be injector problem, look into putting a lift pump. When it limps it wil throw a code, bring it to someone who can put it on a computer when its in limp mode.

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This was all deleted last night.

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I'm aware. There's multiple reasons it could be in limp mode. I just threw the cat out there because that was my expirience.

Call your tuner first...he may have missed something(doubt it though)

What exactly was it doing before?
Symptoms before reduced power.
How it acted after codes were cleared...i.e. goes right back to reduced power, shudder, check engine light for a while, then limp.

Did you get(were you able to extract) any codes before it went into limp mode?

What are the current codes?


I'm at LSU orientation with my son, so I will get back with you as soon as I get a chance to respond to any further posts of yours

Were you able to read any or all codes before during or after limp mode ex. P0101

I never recommend getting an efi tune from anyone without at least purchasing the V2 programmer with it...being able to read codes can help self diagnose or use community forums like duramaxforum.com or dieselplace.com thetruckstop.us to get some help

from the reading I've done the wire may be the problem or caused another problem...at worse it could have fry'd the ECM... Or it could be as simple as a bad G201 ground maybe due to the wire you cut.

Does your fuel gauge max out or fluctuate at same time? does temp gauge max out? the engine overheating message maybe due to whatever is popping the P0652(sometimes causes the temp gauge to max out)


Some info from All Data

From ALLDATADIY

Circuit/System Description

The fuel rail pressure (FRP) sensor has a 5-volt reference circuit, a signal circuit, and a low reference circuit. The engine control module (ECM) monitors the voltage on the FRP sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low. The fuel pressure regulator has a solenoid supply voltage circuit and a solenoid control circuit. The ECM controls the fuel pressure regulator, which regulates high pressure fuel that goes to the fuel injector rails and the injectors.

Conditions for Running the DTC

The ignition is ON.
DTCs P0652 or P0653 are not set.
These diagnostics run continuously within the enabling conditions.

Conditions for Setting the DTC

P0192

The ECM detects the signal circuit voltage that is less than 0.254 volts for more than one second.

P0193

The ECM detects that the signal circuit voltage is more than 4.75 volts for more than one second.

Action Taken When the DTC Sets


DTCs P0192 and P0193 are Type A DTCs.
The ECM commands the engine to operate in the Reduced Engine Power mode.
The message center displays Reduced Engine Power.

Conditions for Clearing the MIL/DTC

DTCs P0192 and P0193 are Type A DTCs.

Circuit/System Verification

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.


1. Verify that DTCs P0652 or P0653 are not set.

* If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. See: Diagnostic Trouble Code Descriptions


1.Observe the Fuel Rail Pressure Sensor parameter with a scan tool. During engine cranking, the pressure should be at least 10 MPa. With the engine running at idle, the pressure should be close to the Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Fuel Rail Pressure Sensor should closely match each other.
2.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

Important: Fuel pressure control will be disable if DTC P0087, P0088, P0192, or P0193 are set. Codes must be cleared to enable the device control.


1. Ignition OFF, disconnect the FRP sensor connector.
2.Turn ON the ignition, with the engine OFF.
3.Observe the Fuel Rail Pressure Sensor parameter with a scan tool The fuel pressure should be 200 MPa (29,000 psi).

*
If the fuel pressure is 0 MPa (0 psi), test the FRP sensor signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

1. Probe the signal circuit terminal 2 with a test lamp connected to ground. The test lamp should not illuminate.

*
If the test lamp illuminates, test the signal circuit for a short to voltage.

1. Connect a fused jumper between the FRP signal circuit terminal 2 and the low reference circuit terminal 1 and observe the Fuel Rail Pressure Sensor parameter with a scan tool. The fuel pressure should be 0 MPa (0 psi).

*
If the fuel pressure does not go to 0 MPa (0 psi), test the FRP sensor signal circuit and the low reference circuit for an open. If the circuit tests normal, replace the ECM.

1. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.

*
If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the ECM.
If greater than the specified range, test the 5-volt reference circuit for a short to voltage, If the circuit tests normal, replace the ECM.

I’m looking into changing the fuel rail sensor but good lord that thing is way back in there. Pretty sure that’s a job for a mechanic.

Two thing either happened. Either the tune is causing too much pressure for my old sensor, or the sensor went out while I was trying to blow out my exhaust before doing the delete