SES Lamp P050D P0300 Setting On A Cold Start And/Or a Run Rough Warm with No codes – 2014-2018 Cadillac Chevrolet GMC

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Bulletin No.: PIP5498L Published date: 05/7/2019

Preliminary Information

PIP5498L SES Lamp P050D P0300 Setting On A Cold Start And/Or a Run Rough Warm with No codes

Models

Brand: Model: Model Years:

VIN:

Engine: Transmissions:

from to

Cadillac CTS-V 2016 – 2019 All All 6.2L LT4
All

Cadillac Escalade 2015 – 2019 All All 6.2L L86
All

Chevrolet Camaro 2016 – 2019 All All 6.2L LT1 LT4
All Chevrolet Corvette 2016 – 2019
All All 6.2L LT1 LT4 LT5 All

Chevrolet Silverado LD 2014 – 2019 All All 4.3L, 5.3L, 6.2L L83,
L8B, L86, LV1,

LV3

All

Chevrolet Silverado 1500 (New

Model)

2019 All All 4.3L, 5.3L, 6.2L L82, L84, L87 All

Chevrolet Suburban 2015 – 2019 All All 5.3L L83
All

Chevrolet Tahoe 2015 – 2019 All All 5.3L L83
All

GMC Sierra 2014 – 2019 All All 4.3L, 5.3L,
6.2L L83, L86, LV1, LV3 All GMC Sierra 1500 (New Model) 2019 All
All 4.3L, 5.3L, 6.2L L82, L84, L87, All

GMC Yukon Models 2015 – 2019 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

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

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 P0300 and P050D,

NOTE: PLEASE BE SURE TO FIRST FOLLOW SI. DIAGNOSTICS for P0300 and P050D THEN, IF DTC P050D
FLOWCHART DOES NOT ISOLATE THE CONCERN, THEN THE FOLLOWING MAY BE HELPFUL.

Follow the flow chart for the P0300 to validate that there is not an ignition or mechanical
concerns or without the P0300 set.

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 only the affected injector.

Note: This will need to be done before the engine is disassembled

Note: If the injectors are being replaced on L86, LT1, LT4 or LT5 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 dual-pulse 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 11

Modified 05/15/2017 Created

06/14/2017 – Updated Concern Information 08/08/2017 – Updated Correction Information 10/31/2017 –
Updated Correction Information 12/01/2017 – Updated Correction Information 12/11/2017 – Updated
Model Years 03/22/2018 – Added Parts Note

05/16/2018 – Added the LT5 engine

06/06/2018 – Update the Correction information 06/12/2018 – update to follow Si. for the P0300
05/07/2019 – Updated Model Years

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