Battery Dead Again! 2008 Gmc Sierra

unit731 · May 8, 2008

2008 GMC Sierra Regular Cab Long Bed 4x4

Well, this is the 2nd time the battery went dead. Been away for 5 days.

Same first time. Away for 5 or 6 days. Get back. Go to truck. Battery too weak to turn over engine. Does do an attempt. Battery just too weak to complete engine start.

Charge battery. All fine. Drive every day. All fine.

The only modification to truck is the A.R.E. cap. All wiring looks fine there for rear brake light for cap.

Background:

I ordered truck with optional battery. Truck came thru with regular battery. No note on sticker that the optional battery was deleted. Sticker states I have the optional battery. Dealer did install a 'new' battery - or similiar - as I have never seen what the optional battery looks like. The 'new' battery does have the correct higher CCA - or higher CCA than the regular battery. I have no idea where they obtained the optional battery.

What I have now is: 48-7YR AC Delco. This is in the truck now - and supposedly the optional higher CCA battery.

Any ideas?

VMax2007 · May 8, 2008

Any ideas?

Bad battery?

J-man67 · May 8, 2008

....yeah, take it in and get a new battery. Single the easy stuff out first.

HawkeyeOC · May 8, 2008

Jeff...always the smart ass

HawkeyeOC · May 8, 2008

The NBS trucks have had battery run down issues not related to the battery. Do those TSB's apply to yours?

99silverado1500 · May 8, 2008

you need a pcm flash, should fix that right up

MS3DALE · May 8, 2008

What I have now is: 48-7YR AC Delco. This is in the truck now - and supposedly the optional higher CCA battery.

I can verify that the 48-7YR is the optional higher 730 CCA battery (RPO code 6C5) The 48-6YR is the standard 600 CCA battery.

I tried ordering mine with the optional HD battery but it was on restriction and wasn't available at the time.

J-man67 · May 8, 2008

so what does said "optional" battery offer that the other doesn't?

handsomerob · May 8, 2008

disconnect positive battery cable set your multi meter to DC Amperage and connect it inline between the positive battery post and the positive battery cable. see if there is a draw with the key off. If so you have a parasitic draw in the system somewhere. Start removing fuses one at a time untill the draw goes away. This will isolate the circuit that has the draw on it, then continue to diagnose inward from there.

MS3DALE · May 8, 2008

Don't know if any of these would apply to you,but here are some bulletins I found in SI in Dealerworld,The forth one down about the roof beacon light switch being left on, I've seen this happen to a few customers that have this option........

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Service Information 2008 GMC Truck Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 1978376

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#02-06-03-008C: Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged, No Start, Slow Cranking, Dim Lights at Idle, Low Generator Output - (May 30, 2007)

Subject: Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery Discharged, No Start, Slow Cranking, Dim Lights at Idle, Low Generator Output

Models: 1990-2008 Passenger Cars and Light Duty Trucks (including Saturn)

2003-2008 HUMMER H2, H3

2005-2008 Saab 9-7X

Any vehicle may have a low voltage display (if equipped with gauges), lights that dim at stop lights, slow cranking, no start, low generator output at idle or dim lights at idle when electrical loads are heavy at idle or under slow driving or infrequent usage conditions. These characteristics may be more noticeable with customer added electrical accessories, or with a discharged battery. These are normal operating characteristics of a vehicle electrical system and no repairs should be attempted unless a proven fault has been diagnosed.

During normal driving conditions, when engine speed is above 1000 RPM, the generator is designed to do two things:

• Supply the current necessary to operate the vehicle's originally equipped electrical devices (loads).

• Recharge/ maintain the battery's state of charge.

The following factors may affect generator and battery performance:

• Non-usage of the vehicle for extended periods of time. The vehicle's computers, clocks and the like will cause the battery state of charge to drop (For example; 30 days in a parking lot and the vehicle may not start because of a dead battery or a vehicle which is driven only a short distance once a week may end up with a discharged battery to the point where the vehicle may not start). This would be considered abnormal usage of the vehicle and the normally expected result for the vehicle battery, generator and electrical systems.

• At idle, vehicle electrical loads may exceed the low speed current (amperage) output of the generator and when this happens the shortfall comes from the battery. This will result in a drop in the electrical system voltage as the battery delivers the additional electrical current to meet the demand. This is equivalent to the brown outs experienced by homes and businesses when the electrical demand is more than the supply. See Figure 1.

• Extended periods of engine idling, with high electrical loads, may result in a discharged battery. Attempting to recharge a battery by letting the engine run at idle may not be beneficial unless all electrical loads are turned "OFF".

• Increased internal generator temperatures from extended idling can also contribute to lower electrical system voltage. As the generator's internal temperature rises, the generator's output capability is reduced due to increased electrical resistance.

The following are some typical examples of electrical loads:

System

Amperage Load

Rear Window defogger

25

Electric AIR Pump

25

Heated Seats

5 Amps per seat

Headlamps (high)

20

Blower Motor (High)

20

Headlamps (low)

15

Brake Lights

6

Windshield Wipers

6

Ignition

6

Depending on the vehicle application, generator current (amperage) output at engine idle speeds of 600-700 RPM can be as low as 35 percent of the full rated output. With enough electrical loads "ON", it is easy to exceed the generator current (amperage) output when the engine is at an idle of 600-700 RPM. This is a normal condition. The battery supplements for short periods of time. Items that affect the vehicle's electrical system current and voltage at idle are the number of electrical loads being used, including add-on accessories, and extended idle times. When the vehicle speed is above approximately 24 km/h (15 mph), the engine/generator RPM is high enough and the generator current (amperage ) output is sufficient to supply the current (amperage) requirements of the vehicle as originally equipped and recharge the battery.

Dimming lights at idle may be considered normal for two reasons:

As the engine/generator speed changes, so will the current (amperage) output of the generator. As a vehicle slows, engine/generator RPM slows, and the current (amperage) output of the generator may not be sufficient to supply the loads, the vehicle system voltage will drop and the lights will dim. Dimming of the lights is an indication that current is being pulled from the battery. If the battery is in a low state-of-charge (discharged condition), the driver will notice a more pronounced dimming than a vehicle with a fully charged battery.

When high current loads (blower, rear defogger, headlamps, cooling fan, heated seats, power seats, electric "AIR" pump, or power windows) are operating or cycled "ON", the generator's voltage regulator can delay the rise in output. This effect, usually at lower engine speeds, can take up to ten seconds to ramp up the generator output. This is done to avoid loading the engine severely. To increase current (amperage) output, additional torque is consumed by the generator. The engine computer (PCM) will ramp up engine/generator speed in small steps so engine speed variations are not noticeable to the driver.

For diagnosis of the battery and or the generator, refer to the appropriate Service Information or Corporate Bulletin Number 05-06-03-002B.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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Service Information 2008 GMC Truck Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 1999010

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#PIT3971A: Multiple Electrical Concerns - keywords audio battery courtesy dead dimming dome door draw drivers fuse harness information intermittent inoperative interior lamp left light lock no passengers power - (Jul 19, 2007)

Subject: Multiple Electrical Concerns

Models: 2007-2008 Cadillac Escalade, ESV, EXT

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007-2008 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some customers may experience one or all of the following concerns.

Rear Door Locks inop

Rear windows Inoperative

"Door" Courtesy Lamps inop or stay on at times.

Rear Speakers Inoperative

Any fuse (related to the rear doors) that is blown.

SIR codes related to the pretensioner

Interior dimming inoperative

Intermittent dead battery

Recommendation/Instructions:

If you experience one or more of the following concerns, check the wiring around the seat belt retractor on the left and right "B" Pillar area. Repair any concerns with the wiring as needed and wrap the entire harness in that area with electrical tape to prevent further concerns.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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Service Information 2008 GMC Truck Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 2037310

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#PIT4412A: Vehicle Will Not Crank / Start At Times - keywords battery crank dead discharge electrical inoperative intermittent no nocrank nostart relay start starter - (Nov 7, 2007)

Subject: Vehicle Will Not Crank / Start At Times

Models: 2007-2008 Cadillac Escalade, ESV, EXT

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007-2008 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

2008 Hummer H2

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some customers may state that intermittently the vehicle will have a no crank / start condition when key is turned to the start position, but if the lock or unlock button on the RKE transmitter is pushed the vehicle will start. There may not be any codes in any of the modules.

Recommendation/Instructions:

If you experience this concern, try a starter relay from a good known vehicle. Reports in the field have found an aftermarket security company is installing an aftermarket starter relay that has internal electronics that will prevent the starter from cranking unless the lock/unlock button on the RKE fob is depressed.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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Service Information 2008 GMC Truck Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 2042965

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#PIT3385D: Roof Beacon Switch Left On Causing Battery Draw - keywords dead lamp light low power relay voltage weak - (Dec 6, 2007)

Subject: Roof Beacon Switch Left On Causing Battery Draw

Models: 2003-2006 Chevrolet Avalanche, Tahoe, Suburban

2003-2008 Chevrolet Silverado, Silverado Classic

2003-2008 GMC Sierra, Sierra Classic

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Battery is discharged for no apparent reason.

Recommendation/Instructions:

A vehicle equipped with RPO VYU (Snow Plow Provision Package) or TRW (Provisions For Roof Mounted Lamp) may not have the roof beacon light connected. If the customer were to inadvertently press the roof beacon switch to the on position the roof beacon indicator will illuminate on the switch. If the ignition is turned off and the beacon switch is left on a battery draw (140-180 Ma) will occur. The roof beacon switch indicator will no longer illuminate when the key is turned off however the roof beacon relay is still energized. It's suggested that the roof beacon switch be turned off before turning the ignition off to avoid a battery drain.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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Service Information 2008 GMC Truck Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 2069355

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#PIT3673B: Battery Goes Dead And Odometer Accumulates Mileage / kilometers When Dinghy Towing - keywords cluster crank IPC low mile nocrank tow - (Feb 21, 2008)

Subject: Battery Goes Dead And Odometer Accumulates Mileage/Kilometers When Dinghy Towing

Models: 2003-2008 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe

2003-2008 GMC Sierra, Sierra Classic, Yukon, Yukon XL

2003-2008 Hummer H2

2008 Chevrolet Tahoe Hybrid

2008 GMC Yukon Hybrid

With Automatic Transmission

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Important: Please reference the owner's manual and/or Bulletin 00-00-89-008D to determine if your vehicle is able to be dinghy towed.

You may experience a concern of the battery going dead and the odometer accumulating mileage/kilometers when dinghy towing. Some owner's manuals direct the customer to leave the ignition key in the accessory position when towing the vehicle.

Recommendation/Instructions:

The key should be turned to the off position when towing. Vehicles equipped with an automatic transmission no longer use a steering column lock feature thus allowing the key to be placed in the off position to prevent the battery from draining and mileage accumulating on the odometer when towing.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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Service Information 2008 GMC Truck Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 2088738

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#PIT4613: Intermittent No Crank And/Or Discharged Battery - keywords charge dead draw fuse generator load low - (Mar 31, 2008)

Subject: Intermittent No Crank And/Or Discharged Battery

Models: 2007-2008 Cadillac Escalade Models

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007-2008 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some owners may comment of an intermittent no crank and/or dead battery. This concern could be caused by a loose connection at the 175 Amp Mega Fuse located on the passenger side of the cowl. A poor connection at this fuse can either cause the battery not to charge while the vehicle is running and/or no power to the UBEC when trying to crank the vehicle. In either case, the end result will likely be a no crank concern.

Recommendation/Instructions:

Check for proper torque of the 175 Amp mega fuse nuts. If either of the nuts is below spec, remove the nuts and inspect the fuse, cables, nuts and holder for corrosion, arcing, or signs of overheating. Replace any damaged components and retorque to spec.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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MS3DALE · May 8, 2008

so what does said "optional" battery offer that the other doesn't?

Higher CCA...730 vs. 600 for the standard battery.

MS3DALE · May 8, 2008

Heres the one on reprogramming the BCM...But it ONLY pertains to the 2007 model year.........

Service Information 2007 GMC Truck Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 2009971

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#06-06-03-013B: Intermittent Low Battery Voltage, Engine Will Not Crank, Cranks But Will Not Start, Charging System Light On, Service Battery Charging System Message DIsplayed, DTC B1405, B1516 Set (Reprogram BCM) - (Sep 11, 2007)

Subject: Intermittent Low Battery Voltage, Engine Will Not Crank, Engine Cranks But Will Not Start, Charging System Light On, Service Battery Charging System Message Displayed, DTC B1405 and/or B1516 Set (Reprogram BCM)

Models: 2007 Cadillac Escalade Models

2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2007 GMC Sierra, Yukon Models

1500 and 2500 Series Vehicles Only

Condition

Some customers may comment of one or more of the following conditions:

• Charging system light on

• Service battery charging system message displayed

• Intermittent low battery voltage

• Vehicle will not crank

• Vehicle cranks but will not start

• Diagnostic Trouble Codes (DTCs) B1405 and/or B1516 may be set

Cause

This condition may be caused by Body Control Module (BCM) calibrations that create a lower battery state of charge than intended in low electrical power usage modes.

Correction

Do This

Don't Do This

Reprogram the BCM.

Do NOT replace the BCM or battery current sensor.

A revised calibration has been developed to address these conditions. Technicians are to reprogram the BCM using SPS with the latest software available on TIS2WEB. Refer to the Body Control Module Programming and Setup procedure in SI (Document ID# 1741198). As always make sure your Tech 2® is updated with the latest software version.

Additional Diagnostic Tips

Usually if a vehicle will start and then not start in a very short period of time, the condition may be created by a loose or corroded connection. In most situations a battery in a good state of health cannot be drained within minutes without a major and most likely very obvious short. The following items are also possible areas of starting and charging system concerns and should be considered as a part of your diagnosis. For more information refer to the Symptoms -- Engine Electrical diagnostic procedure in SI (Document ID# 1703276).

Verify the battery cable connections. It is possible for the negative or positive terminal connector nut to tighten without making a good electrical connection on the battery terminal. The top of the negative battery post should be slightly above the top of the cable clamp.

Verify the battery condition and state of charge using the Midtronics tester and a VAT40 or equivalent tester. Refer to the following diagnostic procedures in SI for additional information.

• Battery Common Causes of Malfunction (Document ID# 1703244)

• Battery Inspection/Test (Document (ID# 1703241)

• Battery Charging (Document ID# 1703243)

Verify proper operation of the charging system. Refer to the Charging System Test procedure in SI (Document ID# 1703783).

Verify that the vehicle does not have a parasitic battery drain. Refer to the Battery Electrical Drain/Parasitic Load Test procedure in SI (Document ID# 1741191).

Verify that the front and/or rear Heating, Ventilation and Air Conditioning (HVAC) blower motor turns off with the key in the OFF position. If the blower motor stays on, refer to the Blower Motor Always On diagnostic procedure in SI (Document ID# 1701247).

Ask the customer if they use the accessories (Radio, DVD player, etc.) with the key in the ON position but with the engine off. This may contribute to a low battery state of charge and difficulty cranking the engine. If the customer uses their accessories with the engine off ask them to turn the key to the ACC position instead of the ON position.

If the vehicle is equipped with aftermarket accessories, verify that they are not a source of concern. Remove or disable if necessary and retest the vehicle. Refer to the Checking Aftermarket Accessories procedure in SI (Document ID# 816776).

Verify that there are no loose connections at the 175 amp mega fuse.

Verify that the Retained Accessory Power (RAP) system is operating properly. The radio and accessories should shut off once the key is removed from the ignition and the driver's door is opened. For more information refer to the Retained Accessory Power (RAP) Malfunction procedure in SI (Document ID# 1776533).

Refer to the following Bulletins and PIs for additional areas of concern.

• A fuel pump relay sticking concern. Refer to Corporate Bulletin number 06-06-03-011B.

• An ignition switch concern and a loss of GM LAN data due to an unwanted ground. Refer to Corporate Bulletin 06-08-45-010.

• A rear door lock relay sticking concern. Refer to Preliminary Information bulletin PIT3984 (Document ID# 1820437).

Check circuit 1240 (Red/White wire) for a short to ground in the driver side or circuit 1340 (Red/White wire) passenger side "B" pillar area near the seat belt retractor. See Document ID# 1740425 for a copy of the wiring diagram for circuit 1240 that goes to the driver side and circuit 1340 that goes to the passenger side windows.

Caution: Circuit 1240 is protected by a 25 amp circuit breaker (LT DRS) and may be hot to the touch if the circuit is shorted to ground.

Circuit 1340 is protected by a 25 amp circuit breaker (RT Doors) and may be hot to the touch if the circuit is shorted to ground.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

N4808*

Body Control Module Reprogramming with SPS

0.4 hr

Add

Diagnosis Time

0.0-0.3 hr

*This labor operation number is for bulletin use only. This number will not be published in the Labor Time Guide.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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