GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Vehicle Care 323
normal idle speed for at least five minutes
while the vehicle is parked. If the warning is
still there, turn off the engine and get
everyone out of the vehicle until it
cools down.
If there is no sign of steam, idle the engine
for five minutes while parked. If the warning
is still displayed, turn off the engine until it
cools down.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and
the ENGINE POWER IS REDUCED message
displays, an overheat protection mode which
alternates firing groups of cylinders helps to
prevent engine damage. In this mode, a loss
in power and engine performance will be
noticed. This operating mode allows the
vehicle to be driven to a safe place in an
emergency. Driving extended distances
and/or towing a trailer in the overheat
protection mode should be avoided.
If the engine or transmission detects an
impending hot fluid condition, then the
transmission may force upshifts to limit
temperatures. Downshifts may also be
prevented in this instance. Normal operationmay continue unless the display indicates
there is a hot condition and engine should
be idled.
Caution
After driving in the overheated engine
protection operating mode, the engine oil
will be severely degraded. Any repairs
performed before the engine is cool may
cause engine damage. Allow the engine
to cool before attempting any repair.
Repair the cause of coolant loss, change
the oil, and reset the oil life system. See
Engine Oil
0314.
Engine Fan
If the vehicle has the Duramax diesel
engine, see the Duramax diesel supplement.
The vehicle has a clutched engine cooling
fan. When the clutch is engaged, the fan
spins faster to provide more air to cool the
engine. In most everyday driving conditions,
the fan is spinning slower and the clutch is
not fully engaged. This improves fuel
economy and reduces fan noise. Under
heavy vehicle loading, trailer towing, and/or
high outside temperatures, the fan speed
increases as the clutch more fully engages, so an increase in fan noise may be heard.
This is normal and should not be mistaken
as the transmission slipping or making extra
shifts. It is merely the cooling system
functioning properly. The fan will slow down
when additional cooling is not required and
the clutch partially disengages.
This fan noise may be heard when starting
the engine. It will go away as the fan clutch
partially disengages.
Power Steering Fluid
The power steering fluid reservoir is in the
engine compartment on the driver side of
the vehicle. See
Engine Compartment
Overview 0313 for reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power
steering fluid unless there is a leak
suspected in the system or an unusual noise
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
330 Vehicle Care
General Motors LLC, and is not limited to
any particular part, component or system of
the vehicle manufactured by General Motors
LLC. Defects in design, assembly or in any
part, component or system of the vehicle as
manufactured by General Motors LLC, which,
at the time it left General Motors LLC’s
control, caused noise emissions to exceed
Federal standards, are covered by this
warranty for the life of the vehicle.
TAMPERING WITH NOISE CONTROL
SYSTEM PROHIBITED
Federal law prohibits the following acts or
the causing thereof:1. The removal or rendering inoperative by any person, other than for purposes of
maintenance, repair, or replacement, of
any device or element of design
incorporated into any new vehicle for
the purpose of noise control prior to its
sale or delivery to the ultimate purchaser
or while it is in use; or
2. the use of the vehicle after such device or element of design has been removed
or rendered inoperative by any person. Among those acts presumed to constitute
tampering are the acts listed below.
Insulation:
Removal of the noise shields or any
undercab insulation.
Engine:
Removal or rendering engine speed
governor, if so equipped, inoperative so as
to allow engine speed to exceed
manufacturer specifications.
Modification of the engine control system or
calibration.
Fan and Drive:
.Removal of fan clutch or rendering clutch
inoperative.
.Removal of the fan shroud.
Air Intake:
.Removal of air cleaner silencer.
.Reversing air cleaner cover.
Exhaust:
.Removal of muffler, catalytic converter,
and/or resonator.
.Removal of exhaust pipes and exhaust
pipe clamps.
Automatic Transmission Shift Lock
Control Function Check
(Mechanical Shifter)
{Warning
When you are doing this inspection, the
vehicle could move suddenly. If the
vehicle moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room around the vehicle.
It should be parked on a level surface.
2. Apply the parking brake. Be ready to apply the regular brake immediately if
the vehicle begins to move.
3. With the engine off, turn the ignition on, but do not start the engine. Without
applying the regular brake, try to move
the shift lever out of P (Park) with
normal effort. If the shift lever moves
out of P (Park), contact your dealer for
service.
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Vehicle Care 339
FusesUsage
6 –
7 ELM 4 –Electronic
Lighting Module 4
8 –
9 –
10 ELM 6 –Electronic
Lighting Module 6
11 BCM 3 –Body Control
Module 3
12 Rear Window Defogger
13 Washer Front
14 –
15 –
16 –
17 IECL 1
19 DC/AC Inverter
20 IECR 2 (LD)/EBCM2 (HD) 21 –
22 IECL 2
24 Fuel Heater (DSL) Fuses
Usage
25 EBCM 1 –Electronic
Brake Control Module 1
26 –
27 Horn
28 Parking Lamp Mirror/ Grill (LD)/Parking Lamp
Left (HD)
29 Parking Lamp Right (HD)
30 ELM 3 –Electronic
Lighting Module 3
31 ELM 1 –Electronic
Lighting Module 1
32 –
33 Not R/C
34 Radars (LD) 37 MISC IP Headliner Ignition
38 Seat Fan Ignition
39 Trailer Ignition Module
40 Misc Ignition 41 Trailer Parking Lamp Fuses
Usage
42 Tail Lamp Left (HD)
44 DEFC/ICCM Ignition (LD/ HD)/FTZM Ignition (HD)
45 Secondary Axle Motor
46 Engine Control Module Ignition
47 –
48 –
49 Transmission Auxiliary Oil Pump (LD)
50 A/C Clutch 51 Transfer Case Control Module
52 Front Wiper
53 Center High-Mounted Stop Lamp
54 Tail Lamp Right (HD) 55 Trailer Back-up Lamp
56 SADS (LD)/Fuel Tank Zone Module 2 (HD)
57 TTPM/SBZA
58 Starter Motor (LD)
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
340 Vehicle Care
FusesUsage
60 Powertrain Sensor 2 (DSL)
61 Active Hydraulic Steering (HD)
62 DEFC Batt 1/CVS
63 Trailer Brake
65 –
66 Cooling Fan Motor Left (LD)
67 –
68 DEFC Batt 2
69 Starter Pinion (LD Gas)/ Starter Motor (HD)
71 Cooling Fan Lower (LD)
72 Cooling Fan Right (LD)
73 Trailer Stop/Turn Lamp Left
74 Trailer Interface Module 2
75 Integrated Chassis Control Module
76 Electric RNG BDS Fuses
Usage
78 Engine Control Module
79 Cabin Cool Pump 17W (LD)/Auxiliary
Battery (HD)
80 Powertrain Sensor 1 (DSL)
81 Trailer Stop/Turn Lamp Right
82 Trailer Interface Module 1
83 FTZM 1
84 Trailer Battery 85 –
86 Engine Control Module 87 Injector B Even
88 O2 B Sensor
89 O2 A Sensor
90 Injector A Odd 91 Engine Control Module Throttle Control (HD) Fuses
Usage
92 Cool Fan Clutch (HD DSL)/Aeroshutter
(LD/HD)
Relays Usage
5 Rear Window Defogger
18 DC/AC Inverter
23 Fuel Heater (DSL)
35 Parking Lamp
36 Run/Crank
43 Secondary Axle Motor
59 A/C Clutch
64 Starter Motor (LD)/Cool Fan Clutch (HD DSL)
70 Starter Pinion (LD Gas)/ Starter Motor (HD)
77 Powertrain