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ASEMaster35yrs, Chevy Technician
Category: Chevy
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Experience:  ASE Certified since 1972,Master Auto tech,Heavy Truck Tech ,chev dealer tech
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Chevrolet Silverado 2500 HD LT: I have some diagnostic codes

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I have some diagnostic codes that I would like to know what they mean. Thank you. They are P2563, P2564 and one more that pertains to the turbo but I don't have it with me at the moment.

Hi, glad to be of help.

Both P2563 and P2564 are turbo codes. Could be a bad wire to vane position sensor. First check Battery condition/connections and wiring to vane position sensor and repair as necessary.

P2563- Turbocharger Boost Control Position Sensor Performance

P2564- Turbocharger vane control position sensor low voltage


Once these tucks start setting turbo vane sensor out of range or turbo vane position not learned codes, it means the turbo is failing or has failed. If they still set the code after any wiring damage has been repaired, look to the actual turbo, not any sensors, being the problem. A new sensor comes with the new turbo, so don't waste money buying one. Be sure to have the problem diagnosed by a qualified shop before spending the money.

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Thank you for your excellent feedback. Thank you for using just answer.
Customer: replied 3 years ago.
Is there anyway that I can check the sensor and solenoid? I have the turbo off of the truck now. I'm going to install a rebuild kit. The cam bearing didn't spin and it is oiling fine. When you spin it by hand it does have a tight spot occasionally. There is no noticeable slack. Is there anything I need to know to make the rebuild job go right? I was pulling a tractor and the truck overheated and the transmission got hot, is that a result of the turbo going out? They other codes that I mentioned yesterday was P0046, P0847, P0700.

I don't recommend rebuilding the turbo yourself unless you've done them before. They are critically balanced and easily damaged, they must spin freely and continuously. You don't want pieces of turbo going into your engine. For peace of mind, get a new or rebuilt one. With a new one, a new sensor comes with it.

You'll need an appropriate scan tool such as Tech2 and multimeter. To test the sensor, Uplug the sensor, turn on the key, and check the three wires (unplugged) with a digital multimeter. One should be 5V, one is ground, and the third should not be 5V, but rather open or near open (well over 10k Ohm). If that checks good, key off, and test the position sensor looking at it as if it were a rheostat (it is). Using the wire data you just acquired at link below, (which is 5V, ground and signal), hand actuate the sensor, measuring resistance between the 5V pin and the signal pin. Are any anomalies noted? See this link:

P0700-Transmission Control System Malfunction

This code states that we have a trans problem ( all 700 codes relate to drivetrain) and you need to read on to find all the related codes. When I say read on, I mean scan further because P0700 only tells you which computer picked up the problem. In this case it is the TCM ( transmission control module).

P0847 -Transmission Fluid Pressure Sensor/Switch 'B' Circuit Low

This is for Transmission pressure switch d stuck closed. This code can be caused by any of the following 1)A short in the wiring for the pressure switch D circuit, Which would be wire "202" pin 2 in the red connector at the transmission TCM, "Mounted to the radiator" Or 2) A Defective D solenoid 3)A sticking shift valve in the valve body or a short in the wiring from the transmission control module to the transmission.

P0046- Turbocharger Vane Control Position Performance

DTC P0046

Circuit Description

The position of the turbocharger vanes is controlled by the
engine control module (ECM). The ECM utilizes a turbocharger vane control
solenoid valve and a turbocharger vane position sensor to control the
turbocharger vanes. When the engine is not under load, the turbocharger vanes
are in an open position, or no boost condition. When the engine is under load,
the ECM commands the control solenoid valve to close the turbocharger vanes,
thus increasing the boost. The ECM will vary the boost dependant upon the load
requirements of the engine. The vane control solenoid valve uses 2 circuits, a
control circuit and a low reference circuit. The ECM uses a pulse width
modulation (PWM) on the control circuit to control the solenoid valve. The ECM
provides a ground on the low reference circuit. If the ECM detects that the
commanded position of the turbocharger vanes does not match the actual
position, DTC P0046 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0046 Turbocharger Vane Control Position Performance

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The ECM detects that the commanded position of the
turbocharger vanes does not match the actual position.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator
lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs
and fails.

The control module records the operating conditions at the
time the diagnostic fails. The first time the diagnostic fails, the control
module stores this information in the Failure Records. If the diagnostic
reports a failure on the second consecutive ignition cycle, the control module
records the operating conditions at the time of the failure. The control module
writes the operating conditions to the Freeze Frame and updates the Failure

Conditions for Clearing the MIL/DTC

  • The control module turns OFF the malfunction indicator
lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and
does not fail.

  • A current DTC, Last Test Failed, clears when the
diagnostic runs and passes.

  • A history DTC clears after 40 consecutive warm-up cycles,
if no failures are reported by this or any other emission related diagnostic.

  • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

If any service has been performed on the turbocharger or on
the turbocharger components, a turbocharger relearn must be performed. Failure
to perform the turbocharger learn procedure may cause this DTC to set. Refer to
Turbocharger Learn Procedure .

For an intermittent condition, refer to Intermittent
Conditions .

Did you mean P0446?
If so, that is a code for EVAP Vent System performance. It is usually caused by
a bad Vent Solenoid Valve or a bad Purge Valve Solenoid. There is a General
Motors TSB out on the problem in which the VSV must be replaced and the EVAP
vent tube gets relocated up to the transmission tunnel.

Turbo repair video

I don't have any videos that are vehicle specific but these
will give you some idea of what you'll be facing if you try rebuilding

Good luck with your project.