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Ask Derek Werner Your Own Question
Derek Werner
Derek Werner, ASE Certified Technician
Category: GM
Satisfied Customers: 135
Experience:  ASE Master Technician, L1 Advanced level specialist
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I cannot start my 2009 Yukon Hybrid....tried boosting with

Customer Question

I cannot start my 2009 Yukon Hybrid....tried boosting with two good batteries and had it on the charger overnight.....I get a message on the dash..."check hybrid system."
I am a long way from my dealer.....a tow job would be ultra expensive....any suggestions?
Submitted: 1 year ago.
Category: GM
Customer: replied 1 year ago.
I received a new password ***** need to sign in.
Customer: replied 1 year ago.
The message on the dash says, "service the hybrid system." What does this mean?
Customer: replied 1 year ago.
When can I expect to hear from you?
Expert:  Derek Werner replied 1 year ago.

Hello and welcome!

Do you have access to a scan tool to retrieve fault codes from the vehicle?

Two mode hybrid systems does not use a conventional starter that is powered by the 12v battery. The electronic motors inside the transmission is what starts the vehicle, the 300 volt battery cranks the engine.

A "Jump Assist" procedure is available, but must use a capable scan tool to place the system into Jump Assist mode.
Also, the hybrid battery must be above 194 V to initiate Jump Assist.
Anytime a battery charger or booster pack is connected to the 12 V battery, the ignition key should always be in the OFF position.

A service hybrid system message indicates a fault code in the hybrid 300v system causing the vehicle not to start.

Customer: replied 1 year ago.
I am located at a seasonal resort area with no service station nor mechanics so looks like I am hooped.
Expert:  Derek Werner replied 1 year ago.

I am so sorry to hear that, was the key left on and the 12v battery died?

Did you leave the battery on a charger or just tried to jump start?

You have only one option to try and reset the system.

1. Ignition key OFF, disconnect the 12 V battery negative cable and positive cable.

2. Wait 10 minutes.

3. Hold the cables together for 2 minutes, or use a jumper wire.

4. Reconnect the 12 V battery cables.

Please be aware, that by doing this procedure it has a chance activate the back up battery in the On Star system. the battery will need to be replaced to clear the codes and the red light on the mirror.