Bulletin No.:

Service Bulletin

Date:

20-NA-179
October, 2020

TECHNICAL
Subject:

Malfunction Indicator Lamp (MIL) Illuminated – DTCs P0521 and/or P06DD Set

Brand:

Model:

Chevrolet

Corvette

Model Year:

VIN Breakpoint:

from

to

from

to

2020

2020

SORP

September
10, 2020

Engine:

Transmission:

6.2L (LT2)

—

Involved Region or Country

North America

Condition

Some customers may comment that the MIL is illuminated.
Some customers may also comment that the MIL will illuminate and then shut off.
Some technicians may find one or more of the following DTCs set in the Engine Control
Module (ECM):
• P0521: Engine Oil Pressure Sensor Performance
• P06DD: Engine Oil Pressure Control Valve Performance

Cause

This condition may be caused by an unseated engine oil pressure control valve (OCV).

Correction

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Note: If a vehicle comes in with one of these DTCs, follow SI for both DTCs to ensure
there is not an electrical fault or other hardware concern. After diagnosis has been
performed and no issues are found electrically, then it will be necessary to remove the
engine oil pan and inspect for a unseated engine oil pressure control valve, which is
mounted on the bottom of the engine oil pump.
If P0521 and P06DD DTCs are present, then a redesigned oil pressure control valve
retainer clip (1) may be necessary. Refer to the Service Procedure section below.

Copyright 2020 General Motors LLC. All Rights Reserved.

Page 2

October, 2020

Bulletin No.: 20-NA-179

Service Procedure
1. Remove the engine oil pan. Refer to Oil Pan
Replacement in SI.

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Note: The generator may need to be repositioned to
gain access to the main cap side bolts.
2. Remove the main cap side bolts (1).
Important: When removing the main bearing cap be
careful not to damage the main bearing or journal
surface of the crankshaft. Please set the main bearing
cap in a safe place so no debris or damage could occur.
3. Remove and discard the bolts (2) that secure the
#1 main bearing cap.

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4. Inspect the OCV:
• If you find this oil pressure control valve
dislodged (1), it will be necessary to install a
redesigned oil control valve retainer.
5. Disconnect the oil pressure control valve electrical
connector and position aside.

Bulletin No.: 20-NA-179

October, 2020

Page 3

Important: Do not use any tools to tap the pressure
control valve into place. Only install the pressure
control valve by pushing on the body of the valve
by hand.
8. Install the new retainer from the front of engine
towards the rear as shown in the graphic above.

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Note: Remove the existing oil pressure control valve
retainer by pulling towards the rear and discard. You
will be installing a newly designed retainer during
installation.
6. Push in the retainer and remove the oil pressure
control valve and set aside.
7. Once the retainer is removed, inspect the oil
pressure control valve for any signs of damage and
ensure the O-ring is not cut.
⇒ Apply a small amount of clean engine oil to the
pressure control valve and reinstall ensuring it
is seated correctly.

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9. When the retainer is installed, there should be
about 2 to 3 mm of clearance between the retainer
and the oil pump body as shown above.
⇒ Ensure the pressure control valve and retainer
are correctly installed.
10. Ensure the cap and bearing are VERY CLEAN and
apply assembly lube prior to installation.
11. Install the front main bearing cap with new bolts.

Tighten
Tighten the bolts to specifications. Refer to
Fastener Specifications in SI.
12. If removed, install the generator.
13. Install the engine oil pan. Refer to Oil Pan
Replacement in SI.

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Page 4

October, 2020

Bulletin No.: 20-NA-179

Parts Information

Warranty Information

Important: **The Oil Pump Control Valve (OCV)
Retainer can be obtained from the Warranty Parts
Center (WPC) using the TSP Dealer Request Form
located on Global Connect