Bulletin No.: PIP5498G
Published date: 03/22/2018

Preliminary Information
PIP5498G SES Lamp P050D P0300 Setting On A Cold Start And/Or a Run Rough Warm with No codes
Models
Brand:

Model:

Model Years:

VIN:
from

Engine:

to

Transmissions:

Cadillac

CTS-V

2016 - 2018

All

All

6.2L LT4

All

Cadillac

Escalade

2015 - 2018

All

All

6.2L L86

All

Chevrolet

Camaro

2016 - 2018

All

All

6.2L LT1 LT4

All

Chevrolet

Corvette

2016 - 2018

All

All

6.2L LT1 LT4

All

Chevrolet

Silverado 1500

2014 - 2018

All

All

4.3L, 5.3L, 6.2L L83, L86, LV1, LV3

All

Chevrolet

Suburban

2015 - 2018

All

All

5.3L L83

All

Chevrolet

Tahoe

2015 - 2018

All

All

5.3L L83

All

GMC

Sierra 1500

2014 - 2018

All

All

4.3L, 5.3L, 6.2L L83, L86, LV1, LV3

All

GMC

Yukon Models

2015 - 2018

All

All

5.3L, 6.2L L83, L86

All

Attention: GM Technical Assistance continues to receive Dealer calls on a concern of DTC P050D and P0300 ,with the
engine disassembled with a no trouble found.
Involved Region or Country North America

A vehicle may have a concern of DTC P050D setting along with a P0300 after a cold start up.
Condition

White smoke and/or coolant odor may come from exhaust for an extended period of time at cold start as
well.
It may also Run rough when warm, slight knock, no codes setting.

Cause

Coolant getting into the cylinders

Correction:
Technical assistance is currently receiving calls after the engine has been disassembled with no trouble found before completing SI
diagnostics for DTC P050D,

PLEASE BE SURE TO FIRST FOLLOW SI. DIAGNOSTICS THEN, IF DTC P050D FLOWCHART DOES NOT ISOLATE THE
CONCERN, THEN THE FOLLOWING MAY BE HELPFUL.
When completing the flow P050D chart, be sure you are checking the injector balance rates while the engine is cold.
Be sure to record the injector balance rates and attach to the work order.
If an injector concern is found, replace all the injectors on the affected bank.
Note: This will need to be done before the engine is disassembled
Note: If the injectors are being replaced on L86, LT1 or LT4 there are three different flow rates injectors offered. Be sure to install the
same flow rate injectors back into the engine by checking the part number on the injector housing. Mixing the flow rates will
cause drivability concerns, DTC setting and repeat injector replacements.

Code P050D Description
During a cold start, the engine control module (ECM) commands dual-pulse mode during Open Loop operation to improve cold start
emissions. In dual-pulse mode, the fuel injectors are energized twice during each injection event. As with misfire diagnosis, in dualpulse mode the ECM monitors the crankshaft position sensor and the camshaft position sensor to calculate crankshaft rotation speed.

In normal operation, optimum fuel delivery during dual-pulse mode produces a steady crankshaft rotation speed. If the variations of
crankshaft rotation speed exceed a calibrated value, the code P050D will be set.
Misfires on start up only, with high rates always on one cylinder, can be suspect for coolant entry at the liner to deck face casting or
the casting line in the intake port of the cylinder head.
To inspect for this concern, add coolant dye to the system, run engine through warm up, pressurize the cooling system after warming
the engine to operating temperature (let the engine cool overnight) and inspect the suspect cylinder with a borescope for coolant dye
evidence.
At times it may be necessary to remove the head for inspection.
If the head casting line is the concern the intake port will be wet with a coolant oil mix.
This could be the cause of a running rough warm concern with or without codes.
The location of where the coolant is running down in the port will also look washed down.

If this is found the cylinder head will need to be replaced.
For coolant entry at the liner to deck face casting of the cylinder bore.

It is hard to see the actual source (pin hole) but it usually streams down the liner so that you can see it with a borescope.(Sometimes)
The top of the piston will be steam cleaned.
Do not confuse residual fuel on the piston crown / surface as coolant. Some fuel residue may be present and can be mistaken as
coolant (reason for the cooling system Dye to be added). Use black light to confirm the liquid is coolant. If this concern is present, do
not replace the cylinder head because that will not repair this concern. Call PQC per the latest version of 16-NA-338, if required,
reference this PI and replace the engine.
Small surface pock marks or pitting appearance on the deck surface is normal and engines should not be replaced for such
appearance as they do not connect to coolant passages and cause a leak path that generate engine misfires. During engine warranty
analysis studies, engines are being replaced for small pitting in the deck face as described above, when the subject cylinder / piston
is saturated with fuel and not coolant

Engines replaced for light / shallow pitting conditions will be returned to the dealership as non-defective.

Version History
Version

7
6/14/2017 - Updated Concern Information
8/8/2017 - Updated Correction Information

Modified

10/31/2017 - Updated Correction Information
12/01/2017 - Updated Correction Information
12/11/2017 - Updated Model Years
3/22/2018 - Added Parts Note

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