Circuit ISUZU KB P190 2007 Workshop Repair Manual

ENGINE DRIVEABILITY AND EMISSIONS 6E–261
DIESELING, RUN-ON SYMPTOM
DEFINITIONS: Engine continues to run after key is turned OFF, but runs very rough. If engine runs smoothly, check
the ignition switch and adjustment.
Step Action Value(s) Yes No
1 Was the “ On-Board Diagnostic (OBD) System Check ”
performed? — Go to Step 2Go to
OBD
System Check
2 1. Perform a bulletin search. 2. If a bulletin that addresses the symptom is found,correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3
3 Was a visual/physical check performed? —Go to Step 4Go to
Visual /
physical Check .
4 Check for a short between battery voltage and the ignition feed circuit.
Was a problem found? — Verify repair Go to Step 5
5 Check the fuel leaking from injector. Refer to Fuel System Diagnostic.
Was the problem found? — Verify repair Go to Step 6
6 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and nomalfunctions have been found, review/inspect the
following:
• Visual/physical inspection
• Tech 2 data
• All electrical connections within a suspected circuit and/or system
Was a problem found? — Verify repair Go to Step 7
7 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 8
8 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify repair —

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ISUZU KB P190 2007

6E–262 ENGINE DRIVEABILITY AND EMISSIONS
BACKFIRE SYMPTOM
DEFINITIONS: Fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.
Step Action Value(s) Yes No
1 Was the “ On-Board Diagnostic (OBD) System Check ”
performed? — Go to Step 2Go to
OBD
System Check
2 1. Perform a bulletin search. 2. If a bulletin that addresses the symptom is found,correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3
3 Was a visual/physical check performed? —Go to Step 4Go to
Visual /
physical Check .
4 Check for proper ignition voltage output with the spark tester.
Was a problem found? — Verify repair Go to Step 5
5 1. Remove the spark plugs and check for gas or oil fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must be determined before replacing the spark plugs.
Was a problem found? — Verify repair Go to Step 6
6 Visually/physically inspect all spark plug high-tension cables. Check for the following conditions:
• Verify that the resistance of all spark plug high- tension cables are less than the specified value.
• Verify that the all spark plug high-tension cables are correctly fitted to eliminate cross-fitting.
• Verify that the all spark plug high-tension cables are not arcing to ground.
Spraying the spark plug high-tension cables with a
light mist of water may help locate an intermittent
problem.
Was a problem found? #1 cyl. 4.4k
Ω
#2 cyl. 3.6k Ω
#3 cyl. 3.1k Ω
#4 cyl. 2.8k ΩVerify repair Go to Step 7
7 Check the fuel pressure. Refer to 6E-108 page “Fuel
System Diagnosis” .
Was a problem found? — Verify repair Go to Step 8
8 Check for an intermittent ignition system malfunction: • Intermittent CKP 58X signal
• Intermittent ignition feed circuit or sensor ground circuit to the crankshaft position sensor.
Was a problem found? — Verify repair Go to Step 9
9 Refer to 6E-108 page “Fuel System Diagnosis ”　 to
determine if there is a problem with fuel delivery.
Was a problem found? — Verify repair Go to Step 10

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–263
10 Check for the following engine mechanical problems(refer to Engine Mechanical ):
• Low compression
• Leaking cylinder head gaskets
• Worn camshaft
• Sticking or leaking valves
• Valve timing
• Broken valve springs
• Camshaft drive belt slipped or stripped
Was a problem found? — Verify repair Go to Step 11
11 Check leakage at exhaust system. Check the intake and exhaust manifold for casting
flash. Refer to Engine Mechanical .
Was a problem found? — Verify repair Go to Step 12
12 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and nomalfunctions have been found, review/inspect the
following:
• Visual/physical inspection
• Tech 2 data
• All electrical connections within a suspected circuit and/or system
Was a problem found? — Verify repair Go to Step 13
13 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 14
14 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify repair —
Step
Action Value(s) Yes No

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–24

1.5 Engine Lubrication System
Lubrication Description
A structural diecast aluminium oil pan is fitted that incorporates an oil suction pipe, an oil deflector and an oil level sensor.
The oil suction pipe is bolted into the oil pan and seals to the bottom of the cylinder block with a gasket. The oil deflector
is bolted to the upper portion of the oil pan and ensures oil supply is maintained under all conditions. The oil level sensor
is mounted through the bottom of the oil pan.
A crankshaft driven gerotor oil pump is mounted to the front of the cylinder block. The pump, which incorporates an
internal pressure-relief valve, draws oil from the oil suction tube through the lower passage in the cylinder block. Oil is
then directed through an upper passage to the left-hand side of the cylinder block where the oil filter adapter is mounted.
The oil filter adapter incorporates a top-access, cartridge style oil filter. The filter is accessed through a screw-on cap tha t
incorporates an oil bypass valve. The oil filter adapter housing incorporates a drain back control valve and a threaded oil
pressure sender. Oil flows through a lower passage within the oil filter adapter and through the oil filter cartridge. Filtered
oil travels back through the upper passage of the adapter and into the engine block.
Oil is then directed up and across the front of the cylinder block, through several drilled passages. These front passages
feed oil to each cylinder head, the passage for the main bearings and piston oil jets, the right-hand and left-hand
secondary idler sprockets and to the primary timing chain tensioner.
Each cylinder head passage directs oil into oiling circuits for the stationary hydraulic lash adjusters (SHLAs) and the
camshaft bearing journals. An additional passage in the cylinder head also directs oil to the secondary timing chain
tensioner.
The oil passage that supplies oil to the main bearings also supplies oil to pressure actuated piston cooling oil jets. Each
oil jet is mounted between opposing cylinder bores and directs oil to the two bores to provide extra cooling and control
piston temperatures.
From the front passages, oil is directed to the front of the block where the right-hand and left-hand intermediate drive
shaft sprockets and the primary timing chain tensioner are mounted. Each camshaft timing chain tensioner relies on a
gasket to maintain an oil reserve after the engine is turned off. All camshaft timing chain tensioners incorporate a small
oil jet to supply an oil spray onto the camshaft timing chain components.
Oil returns to the oil pan, either through the camshaft timing chain area or through the drain back passages on the
outboard walls of the cylinder heads and cylinder block.
1.6 Service Notes
Cleanliness and Care
Throughout this Section, correct cleaning and protection of machined surfaces and friction areas is a part of the repair
procedure. This is considered standard workshop practice, even if not specifically stated.
W hen any internal engine part is serviced, care and cleanliness is extremely important.
W hen components are removed for service, they should be marked, organised or retained in a specific order for
reassembly.
At the time of installation, components should be installed in the same location and with the same mating surface as
when removed.
Any engine is a combination of many machined, honed, polished and lapped surfaces with tolerances that are measured
in thousandths of a millimetre. These surfaces should be covered or protected to avoid component damage.
A liberal coating of clean engine oil should be applied to friction areas during assembly, as the lubrication will protect and
lubricate friction surfaces during the initial engine start-up.
Replacing Engine Gaskets
Re-Using Gaskets and Applying Sealants
• do not reuse any gasket unless specified,
• gaskets that can be reused will be identified in the service procedure, and
• do not apply sealant to any gasket or sealing surface unless specified in the service information.
Separating Components
• Use a rubber mallet to separate components.
• Bump the part sideways to loosen the components.
• Bumping should be done at bends or reinforced areas to prevent distortion of parts.
Cleaning Gasket Surfaces
• W here required, remove all gasket and sealing material from the part using a plastic or wood scraper.
• Care must be used to avoid gouging or scraping the sealing surfaces.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–32

secondary ignition circuit is grounded out during
diagnosis.
A light rattle/tapping noise may indicate a valve train/upper engine concern, while a low rumble/knocking may indicate a
crankshaft, piston or lower engine concern.
Cause Correction
Oil filter anti-drain back valve faulty. Replace the oil filter adaptor, refer to 3.3 Oil Filter
Adaptor.
Incorrect oil viscosity. Drain the engine oil and replace with the correct viscosity
oil, refer to 3.1 Engine Oil.
High camshaft stationary hydraulic lash adjuster (SHLA)
leak down rate. Replace the SHLA as required, refer to 3.21 Stationary
Hydraulic Lash Adjuster.
W orn crankshaft thrust bearing. Inspect and replace the crankshaft and/or bearings as
required, refer to 4.6 Crankshaft and Main Bearings.
Damaged or faulty oil filter by-pass valve. 1 Inspect the oil filter by-pass valve for correct
operation.
2 Repair or replace the oil filter adaptor/by-pass valve as required.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–33

2.9 Upper Engine Noise, Regardless of
Engine Speed
NOTE
A cold piston knock, which disappears in
approximately 1.5 minutes from start up, should
be considered acceptable. A cold engine knock
usually disappears when the specific cylinder’s
secondary ignition circuit is grounded out during
diagnosis.
A light rattle/tapping noise may indicate a valve train/upper engine concern, while a low rumble/knocking may indicate a
crankshaft, piston or lower engine concern.
Cause Correction
Low oil pressure. 1 Perform an oil pressure test, refer to 2.19
Engine Oil Pressure Diagnosis.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.
W orn or loose stationary hydraulic lash adjusters (SHLA)
and/or valve rocker arms.
The SHLAs, rocker arm and roller bearings should be intact
and in the correct position. 1 Clean, inspect and replace the camshaft lash
adjusters as required, refer to 3.21 Stationary
Hydraulic Lash Adjuster.
2 Replace the SHLAs and/or rocker arms as required, refer to 3.21 Stationary Hydraulic Lash Adjuster or
3.20 Rocker Arm.
Incorrect lubrication to the stationary hydraulic lash
adjusters and valve rocker arm. Inspect the following components and repair or replace as
required:
• valve rocker arms, refer to 3.20 Rocker Arm.
• stationary hydraulic lash adjusters, refer to 3.21
Stationary Hydraulic Lash Adjuster.
• oil filter by-pass valve, refer to 3.3 Oil Filter
Adaptor.
• oil pump and suction pipe, refer to 3.17 Oil Pump
Assembly.
• cylinder head oil galleries, refer to 3.22 Cylinder Head
Assembly.
• cylinder block oil galleries, refer to 4.7 Cylinder
Block.
Broken Valve Spring. Replace the valve spring, refer to 3.22 Cylinder Head
Assembly.
Stretched or broken timing chain/s and/or damaged timing
chain sprocket teeth. Replace the timing chains or sprockets as required, refer to
3.16 Timing Chains, Tensioners, Shoes and Guides.
W orn or faulty timing chain tensioner or guide. Replace the timing chains or sprockets as required, refer to
3.16 Timing Chains, Tensioners, Shoes and Guides.
W orn camshaft lobes. Replace the camshaft/s and SHLAs as required, refer to
3.19 Camshaft or 3.21 Stationary Hydraulic Lash
Adjuster.
W orn valve guides and/or valve stems. Inspect and repair or replace valves and valve guides as
required, refer to 3.22 Cylinder Head Assembly.
Stuck valves.
Carbon on the valve stem or valve seat may cause the
valve to stay open. Inspect and repair or replace valves and valve guides as
required, refer to 3.22 Cylinder Head Assembly.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–34

2.10 Lower Engine Noise, Regardless of
Engine Speed
NOTE
A cold piston knock which disappears in
approximately 1.5 minutes from start up should
be considered acceptable. A cold engine knock
usually disappears when the specific cylinder’s
secondary ignition circuit is grounded out during
diagnosis.
A light rattle/tapping noise may indicate a valve train/upper engine concern, while a low rumble/knocking may indicate a
crankshaft, piston or lower engine concern.
Cause Correction
Low oil pressure. 1 Perform an oil pressure test, refer to 2.19
Engine Oil Pressure Diagnosis.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.
W orn accessory drive components.
Abnormalities such as severe cracking, bumps, stretching
or missing areas on an accessory drive belt and/or
misalignment of accessory drive system components. Inspect the accessory drive system, repair or replace
components as required, refer to 3.5 Accessory
Drive Belt.
Loose or damaged crankshaft balancer and pulley
assembly. Repair or replace the crankshaft balancer and pulley
assembly as required, refer to 3.13 Crankshaft Balancer
Assembly.
Detonation or spark knock. Confirm the correct operation of the ignition system, refer to
6C1-2 Engine Management – V6 – Diagnostics.
Loose torque converter bolts. Inspect and tighten the torque converter bolts to the correct
torque specification, refer to 7C4 Automatic Transmission –
4L60E – On-vehicle Servicing.
Loose or damaged flexplate. Repair or replace the flexplate as required, refer to 4.3
Flexplate Assembly.
Oil pump suction pipe loose, damaged or restricted. Clean, inspect and repair/replace the oil pump suction pipe as required, refer to 4.2 Oil Pan and Oil Pump Suction
Pipe Assembly.
Excessive piston-to-cylinder bore clearance. Inspect the piston and cylinder bore and repair/replace
components as required, refer to 4.5 Pistons, Pins,
Rings, Connecting Rods and Big-end Bearings and 4.7
Cylinder Block.
Excessive connecting rod bearing clearance. Inspect the connecting rod, crankshaft and bearings and
repair/replace components as required, refer to 4.5
Pistons, Pins, Rings, Connecting Rods and Big-
end Bearings and 4.6 Crankshaft and Main Bearings.
Excessive piston pin to bore clearance. Inspect the pistons and pins and repair/replace components
as required, refer to 4.5 Pistons, Pins, Rings,
Connecting Rods and Big-end Bearings.
Excessive crankshaft main bearing clearance. Inspect the crankshaft, cylinder block journals, main
bearings and main bearing caps and repair/replace
components as required, refer to 4.6 Crankshaft
and Main Bearings and 4.7Cylinder Block.
Incorrect piston, pin and connecting rod installation.
Pistons must be installed with the mark or dimple facing the
front of the engine. Piston pins must be centred in the
piston pin bore. Confirm the pistons, pins and connecting rods are installed
correctly and repair if required, refer to 4.5 Pistons, Pins,
Rings, Connecting Rods and Big-end Bearings.

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Engine Mechanical – V6 Page 6A1–35

2.11 Engine Noise Under Load
NOTE
A cold piston knock which disappears in
approximately 1.5 minutes from start up, should
be considered acceptable. A cold engine knock
usually disappears when the specific cylinder’s
secondary ignition circuit is grounded out during
diagnosis.
A light rattle/tapping noise may indicate a valve train/upper engine concern, while a low rumble/knocking may indicate a
crankshaft, piston or lower engine concern.
Cause Correction
Low oil pressure. 1 Perform an oil pressure test, refer to 2.19
Engine Oil Pressure Diagnosis.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.
Detonation or spark knock. Confirm the correct operation of the ignition system, refer to
6C1-2 Engine Management – V6 – Diagnostics.
Loose torque converter bolts. Inspect and tighten the torque converter bolts to the correct
torque specification, refer to 7C1 Automatic – 4L60E –
General Information – 4L60E – General Information.
Cracked flexplate. Replace the flywheel/flex-plate as required, refer to 4.3
Flexplate Assembly.
Excessive connecting rod bearing clearance. Inspect the connecting rod, crankshaft and bearings and
repair/replace components as required, refer to 4.5
Pistons, Pins, Rings, Connecting Rods and Big-
end Bearings and 4.6 Crankshaft and Main Bearings.
Excessive crankshaft bearing clearance Inspect the crankshaft, cylinder block journals, main
bearings and main bearing caps and repair/replace
components as required, refer to 4.6 Crankshaft
and Main Bearings and 4.7Cylinder Block.
2.12 Engine Will Not Crank – Crankshaft Will Not Rotate
Cause Correction
Seized accessory drive system component. 1 Remove the accessory drive belt, refer to 3.5
Accessory Drive Belt.
2 Rotate the crankshaft by hand at the balancer pulley or flywheel.
3 Repair or replace accessory drive system components as required.
Hydraulically locked cylinder caused by:
• coolant in cylinder,
• oil in cylinder, or
• fuel in cylinder. 1 Remove the spark plugs and check for fluid, refer to
6C1-3 Engine Management – V6 – Service
Operations.
2 Inspect for broken head gasket/s.
3 Inspect for cracked engine block or cylinder head.
4 Inspect for sticking fuel injector.
5 Repair or replace components as required.
Seized torque converter. 1 Remove the torque converter bolts, refer to 7C1
Automatic – 4L60E – General Information – 4L60E –
General Information.
2 Rotate the crankshaft by hand at the balancer pulley or flywheel.
3 Repair or replace torque converter as required.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–45

Step Action Yes No
10 Inspect for missing, loose or incorrect fasteners.
Did you find any missing, loose or incorrect fasteners? Go to Step 11 Go to Step 12
11 Tighten any loose fasteners to the torque specification as provided in
provided in 6. Torque W rench Specifications.
Replace any incorrect or missing fasteners.
Did you complete the repairs? Go to Step 15 —
12 Inspect for a bent pulley. Did you find any bent pulleys? Go to Step 13 Go to Step 14
13 Replace bent pulleys as required. Did you complete the repair? Go to Step 15 —
14 Replace the accessory drive belt, refer to 3.5 Accessory Drive Belt.
Did you complete the repair? Go to Step 15 —
15 Reinstall the accessory drive belt and operate the system to confirm the repair.
Did you correct the chirp noise? Accessory drive
system OK Go to 2.2
Symptoms, and restart the
diagnosis
Drive Belt Squeal
Definition
Accessory drive belt squealing can be defined as a loud screeching noise caused by a slipping drive belt. Belt squeal is
unusual in multi-rib belts. Drive belt squeal generally occurs when a heavy load is applied to the drive belt, such as an
air-conditioning compressor engagement, snapping the throttle, seized pulley or a faulty accessory drive component.
Diagnostic Aids
If the noise is intermittent, confirm the accessory drive components by varying their loads, making sure they are operated
to their maximum capacity. An overcharged A/C system, restrictions in the power steering pressure circuit or a faulty
generator or coolant pump are likely causes of accessory drive belt squeal.
A loose or incorrectly installed body component, suspension component or other item may be the cause of the noise.
Test Description
The numbers below refer to steps in the diagnostic table.
2 The noise may not be engine related. This step is to confirm the engine is making the noise. If the engine is not making the noise, do not proceed further with this diagnostic procedure.
3 The noise may be an internal engine noise. Removing the drive belt and operating the engine briefly will confirm whether or not the noise is related to the drive belt.
CAUTION
When running the engine with the accessory
drive belt removed, the coolant pump will not
be operating and the engine may overheat if
left unsupervised even for a short period.
NOTE
There may also be a number of DTCs set when
running the engine with the accessory drive belt
removed.
4 Confirms an accessory drive component does not have a seized bearing. W ith the belt removed, test the bearings in the accessory drive components spin free and smooth.
5 Confirms the drive belt tensioner is operating correctly. If the drive belt tensioner is not operating correctly, drive belt tension will not be maintained, resulting in a belt squealing noise
6 Confirms the belt is not too long, which would prevent the tensioner from working as intended. Also, if an excessively long belt has been fitted, it may also be routed incorrectly and may be turning an accessory drive
component in the wrong direction.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–46

7 Misalignment of the pulleys may be caused by one of the following:
• Incorrect mounting of an accessory drive component,
• Incorrect installation of an accessory drive pulley or,
• Bent or damaged pulley.
Test for a misaligned pulley using a straight edge in the pulley grooves across 2 or 3 pulleys. If a misaligned pulley is found, refer to the relevant component service information for the correct installation and removal procedures.
8 This test is to confirm the pulleys are the correct diameter and/or width. Using a known good vehicle, compare the pulley sizes.
Diagnostic Table
Step Action Yes No
1 Did you review the information provided in 2.2 Symptoms, and
perform the required inspections. Go to Step 2 Go to 2.2
Symptoms
2 Confirm the customer complaint. Is there a squealing noise? Go to Step 3 Refer to Diagnostic
Aids in this Section
3 1 Remove the drive belt, refer to 3.5 Accessory Drive Belt.
2 Operate the engine for no more than 40 seconds.
Does the squealing noise still exist? Accessory drive
system OK.
Go to 2.2
Symptoms, and restart the
diagnosis of the noise Go to Step 4
4 Inspect the accessory drive components for a seized bearing and
general malfunctions.
Did you find and correct any seized bearings or general malfunctions
in the accessory drive system? Go to Step 9 Go to Step 5
5 Test the accessory drive belt tensioner for correct operation, refer to
Accessory Drive Belt Tensioner Diagnosis.
Did you find and repair any problems with the tensioner? Go to Step 9 Go to Step 6
6 Inspect the accessory drive belt is the correct length, refer to 3.5
Accessory Drive Belt.
Did you find and repair any problems with the drive belt length? Go to Step 9 Go to Step 7
7 Inspect the accessory drive pulleys for misalignment.
Did you find and correct any misaligned accessory drive pulleys? Go to Step 9 Go to Step 8
8 Check the accessory drive pulleys are the correct size. Did you find and replace any incorrect pulleys? Go to Step 9 Refer to Diagnostic
Aids in this Section
9 Reinstall the accessory drive belt and operate the system to confirm
the repair.
Did you correct the squeal noise? Accessory drive
system OK Go to 2.2
Symptoms, and restart the diagnosis
Drive Belt Whine
Definition
Accessory drive belt whine can be defined as a high-pitched continuous noise that is most likely to be caused by a failed
bearing in one of the accessory drive components.
Diagnostic Aids
The drive belts themselves will not cause a whine. If the noise is intermittent, confirm the accessory drive components by
varying their loads, making sure they are operated to their maximum capacity. An overcharged A/C system, restrictions
in the power steering pressure circuit or a faulty generator or coolant pump are likely causes of accessory drive belt
whine.
Test Description
The numbers below refer to steps in the diagnostic table.

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