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Makes 🢒 GMC_Truck 🢒 2008 🢒 Yukon XL - 4WD 🢒 Bulletins 🢒 (Hybrid) Replacement 12V Battery For The 2 Mode Hybrid - keywords 2 2-mode crank dead draw drain electrical engine hp2 no nocrank start stop two two-mode unwanted

(Hybrid) Replacement 12V Battery For The 2 Mode Hybrid - keywords 2 2-mode crank dead draw drain electrical engine hp2 no nocrank start stop two two-mode unwanted

Subject:(Hybrid) Replacement 12V Battery For The 2 Mode Hybrid

Models:2008 Chevrolet Tahoe Hybrid
2008 GMC Yukon Hybrid
With RPO HP2


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

Condition/Concern:

If you experience a 12 volt under hood battery on the Two-Mode Hybrid Tahoe/Yukon that requires replacement. Please see the following instructions below.

Recommendation/Instructions:

Note: This PI only applies to the 2008 HYBRID Chevrolet Tahoe and GMC Yukon Only.

  1. Test the battery by following the Battery Inspection/Test procedure in SI (Document id: 1991969)
  2. Replace the battery only if the second test shows a "REPLACE BATTERY" or "BAD CELL-REPLACE" result.
  3. Write the test code displayed by the tester on the repair order for any warranty purposes.
  4. Replace the battery with an updated battery GM Part Number: 89022169 or the Equivalent AC Delco Part Number: 48-7YR.

Additional Information: Advise the customer that just like a non-hybrid vehicle, if you don't start the engine the 12 Volt battery will not get charged. The 12 volt battery can be sufficiently depleted to cause a no-crank condition in as little as 20 minutes with the ignition in Acc or Run if the engine has not been started. If the customer wishes to watch a DVD, listen to the radio, tailgate, etc. the engine should be started. Depending upon conditions, the engine may enter the Autostop mode for 30 minutes or more. The 12 volt battery will be charged from the High Voltage battery when the engine is in Autostop. To avoid exhaust gas build-up, discourage starting of the engine if the vehicle is in an enclosed location. Advise technicians to connect an external 12 volt battery charger whenever the ignition must be in the Acc/Run position with the engine OFF. If the vehicle is going to be placed into storage or not driven for 25 days the 12v battery should be disconnected.

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.