First, here is a TSB on just "getting to know" your hybrid:
Bulletin No.: 07-00-89-059C
Date: September 05, 2008
Subject:
Service Guide, Unique Characteristics and Normal Operating Conditions for Two-Mode Hybrid Models:
2009 Cadillac Escalade Hybrid
2008-2009 Chevrolet Tahoe Hybrid
2008-2009 GMC Yukon Hybrid with 2 Mode Hybrid Option (RPO HP2)
Supercede:
This bulletin is being revised to add the 2009 Cadillac Escalade Hybrid. Please discard Corporate Bulletin Number 07-00-89-059B (Section 00 - General Information).
Notice: ^ Diagnosis and repair of Two-mode propulsion systems, two-mode high voltage systems, M99 Transmission, LFA engine, regenerative brake apply systems and HVAC systems MUST be performed by dealers who both sell and service Two-mode Tahoe and Yukon vehicles. Dealers must have the essential tools and personal protective equipment and technicians performing hybrid repairs must have completed all available training prior to proceeding with repairs on the unique hybrid components. ^ If your dealership is not a Two-mode hybrid sales and servicing dealership with a trained technician, then the vehicle must be transferred to a dealership that meets these requirements. SAFETY PRECAUTIONS
Caution: To reduce the risk of severe shock and burns, treat all high voltage cables and connectors as though they are energized until it can be verified that they are not. Caution: Any service to the hybrid system or any related component requires the removal of the key from the ignition. If the key is left in the Run position, failure to remove the key from the ignition could cause the engine to auto-start, and in the Off position, the 300V system could remain active. The first step of disabling the high-voltage system is to remove the key from the ignition, which is designed to open the contactors in the battery pack, beginning the process of powering down the high-voltage system. Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: ^ Identify how to disable high voltage. ^ Identify how to test for the presence of high voltage. ^ Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Failure to follow the procedures exactly as written may result in serious injury or death.
Caution: The hood ajar switch communicates whether the hood is open or closed. If the ignition is in the "on" position and the vehicle is in auto-stop, the engine will restart automatically when the hood is opened. Unique Characteristics and Normal Operating Conditions
Drivers of the Two-mode Hybrid Tahoe or Yukon will experience some operating characteristics that are unique to these vehicles. Due to the quiet nature of the Hybrid Drive system, certain sounds that may have been masked by the engine's natural harmonics will be apparent. Among them is the electric engine cooling fan, the air conditioning compressor and the HVAC blower. In addition to those sounds, the drive motor battery assembly cooling fan, which sounds like the HVAC blower on low speed, may be heard from under the second row seat.
Key Crank Engine Start Sounds Different
This is a normal characteristic of the vehicle. If the engine will not crank, ensure that the 12v battery is sufficiently charged to allow for all of the hybrid control modules to "wake up" and initialize. The Two-Mode Hybrid does not use a conventional 12v starter- it uses one of the electric motors in the transmission to crank the engine that spins the engine faster than a 12v starter, resulting in different than typical starting noise.
Stall During Shift Out of Park Immediately following Engine Crank
This is a normal operating characteristic. Some drivers are able to interrupt the engine start sequence by immediately shifting the transmission out of Park after turning the ignition to Crank. Because the electric motor spins the engine so fast, the engine may appear to be running immediately after Crank but the ECM has not yet started spark and fuel. The ECM will turn off fuel and spark to the engine if it not running and the transmission has been shifted out of Park or Neutral. Inform the customer to wait 1-2 seconds before shifting out of Park or Neutral to ensure that the engine is running and has completed the start sequence.
Engine Restarts in Reverse/Manual Mode from Auto Stop
This is a normal operating characteristic - engine will restart any time the gear selector is in reverse or Manual Mode. Reverse remains in electric mode, however, the engine restarts to provide counter-torque for the internal transmission gears.
Slight Bump in Driveline during Acceleration
This is due to transition from V4 to V8 and vice versa. In Mode 2, the engine is able to operate longer in 4-cylinder mode under light throttle for improved highway fuel economy. As more power is needed, the system will transition in V8 Mode. This is a normal operating characteristic of hybrid powertrain to maximize fuel economy.
Low Pitch Noise during Auto Stop
This is a normal characteristic operation of electric coolant pump or hybrid battery fan. During Auto Stop the engine is not running and the interior cabin is quiet. These pumps run to keep the electronics from overheating, even in cold ambient temperatures. This noise may be more evident during high ambient interior temperatures. Advise the customer to keep the battery vents clear and not to carry cargo in the second row footwell area. The electric coolant pump runs in Autostop to circulate coolant to the HVAC system to maintain cabin temperature. That pump (under the right conditions) will run and may be barely audible.
Tailgate Hard to Close
To improve fuel economy, the tailgate of the Two-Mode Hybrid is made of aluminum, requiring more force to close and fully latch the tailgate.
Cruise Control Resume Operation
The Hybrid System is optimized for highest possible fuel economy. The Two-Mode hybrid vehicle resumes previously set vehicle speed at a rate which provides maximum fuel economy.
Brake Pedal Feel and Brake Pedal Vibration
^ The Two-mode Hybrid System has a unique brake pedal feel. This is because the hydraulic system is not the lone provider of vehicle deceleration. The hybrid system blends in regenerative and hydraulic braking forces depending upon vehicle conditions. Over several braking events, the customer may perceive that they are applying a consistent brake force and yet the vehicle may decelerate at slightly different rates. This is a normal operating characteristic to maximize fuel economy. ^ The Two-Mode hybrid vehicle utilizes a braking system that employs a high-speed electric motor/pump. Pump operation can sometimes be felt in the brake pedal as the system sometimes builds pressure. This is most noticeable to customers who start the vehicle with their foot on the brake pedal. 12 Volt Operation
^ In order to maintain the peak capacity in the 12-volt system, it is recommended that customers allow the vehicle to remain in "run" when parked and attended ONLY AFTER cranking and starting the engine. When the ignition switch has been turned to crank and is set to "run" the engine will run until the desired state of charge in the 300V battery has been reached. At that point, the vehicle will enter auto-stop mode, and the Accessory Power Module (APM) will continue to power the 12-volt system. Failing to allow the APM to power the 12-volt system could cause discharge of the 12-volt battery. Examples of activities that may cause stress on the 12 volt battery include: ^ Tailgate celebrations ^ Usage of the rear seat entertainment system with the vehicle off ^ Listening to the radio for extended periods of time with the vehicle off ^ In the above situations, the recommended operating mode is to start the engine. Normally the vehicle will enter auto-stop mode and as the 12-volt battery needs charging, the system will automatically start the engine to keep the system fully charged. ^ In addition to allowing the APM to power the vehicle's 12-volt system, special care should be taken when storing this vehicle. If the vehicle is to be stored for more than 20 days, the 12-volt battery should be disconnected. If the vehicle is to be stored for more than 60 days, the 12-volt battery should be charged to capacity no less than once every 20 days. ^ You must wait at least 5 minutes after turning the ignition OFF before disconnecting the 12V battery for any reason. This allows the hybrid control modules to process and store internal data. Grind/Growl in 4WD
On 4WD applications, the vehicle may experience a growl or gravel noise from the driveline momentarily during low speed, low RPM maneuvers. This is considered normal gear noise in the transmission.
Whine Sound during Electric Hybrid Operation
In electric drive mode and reverse, the transmission can be heard as the vehicle moves. This is a normal operating characteristic.
No Brake Assist (Hard Pedal) After Disconnecting Battery
Customers or technicians that are disconnecting the battery must wait for a period of at least 5 minutes with the ignition in the "OFF" position without pausing at ACCESSORY, and without applying the brake pedal prior to disconnecting the 12 Volt battery. These steps are necessary to allow the brake system pressure relief procedure to occur. Failure to follow these steps may result in warning lamps and/or DTCs being set pertaining to interruption of the pressure relief procedure. Other vehicle systems may also be affected by not allowing a 5 minute duration for power-down.

 

Second,
There are 14 training courses from GM on the hybrid drivetrain. They are on GMtraining.com, so your tech can access them and learn BEFORE turning a screwdriver.

 

Third,
I've only heard about the reboot procedure, but I find no information on it anywhere. Maybe it is part of the SI and Service Programming System (SPS) that the dealers use.
When I read the procedures for things like removing the hybrid battery or control module, it does not mention this procedure.

 

And fourth,
There is a function of the hybrid system called Jump Assist. Here is the run-down (pun intended):
Jump Assist Description and Operation

Overview

A severely depleted hybrid drive motor battery will not have sufficient energy needed to crank the engine. In this case the accessory power module (APM) may be placed in a special operating mode called Jump Assist. The Jump Assist function allows on vehicle charging of the hybrid drive motor batteries using the 12 volt DC vehicle system.

Operating Functions

In Jump Assist the APM converts the 12 volt DC to high voltage (HV) DC. The high voltage DC can then charge the hybrid drive motor batteries. During this mode of operation the APM and vehicle systems may draw up to 80 amps of current from the vehicles 12 volt DC system. An external 12 volt DC battery charger is required during the Jump Assist mode. In order to guarantee a successful engine start, a minimum of a 20 percent state of charge (SOC) in the hybrid drive motor battery is recommended. Refer to Jump Assist. A successful Jump Assist can be expected to take an extended period of time not less than 20 minutes.

The APM hardware requires a minimum voltage level on the hybrid drive motor battery in order to initiate the Jump Assist function. If there is less than this required voltage level, the hybrid drive motor battery assembly must be replaced.

 

Thanks for all your suggestions and help.. I took my beast to the Cadillac dealer here in Athens. I have to say they have been great. Even though they don't deal with Tahoe's and had never seen a Hybrid before they have been more than eager to help.
They attached the Tech2 to the dashboard .. and couldn't find anything wrong .. and then after giving it an oil change .. she refused to start. Out came the Tech2 and diagnosed the wiring loom to the transmission was the culprit. There is a GM advisory out for it so in the US will be covered by Warranty. Here in Europe we don't have that luxury .. the cost of a replacement €800 or about $1000. I think i will get that back from my third party warranty.
It will take up to two weeks for the part to arrive and will be done in just a few hours!
Oh and with the engine warning light on I decided to get the truck transported to the dealer. When backing off the truck the transporter driver forgot to stow one of his anchor chains and it damaged the front air dam --- another €180 to replace.
I have to say any savings in fuel costs I expected to make are LONG GONE!!!
I'll keep you guys informed about the progress.

 

they order all the related gaskets as they have to pull the pump body to get to the harness and need new gaskets to put it back together properly. My dealer forgot so I got a 'free' loaner for a few extra days. I didn't know that european warranties were different than american warranties...

 

Even overseas, I cannot imagine that they would not repair that known defect for free! I would 100% insist the towing company pays for the air dam damage!
The Caddy dealer should be excited to get the experience, as they have Escalade hybrids, based on the same platform.

 

Fjungman,

Thanks for your posts, very helpful and informative

 

Guys

I thought I should bring you up to date on the progress with my Hybrid and its starting problem.

The answer is - NO PROGRESS.

It has been at the Cadillac Dealer in Athens for TWO Months waiting parts.

They were ordered from GM in US, but not all the them arrived. And of course Greece virtually closes down during the month of August.

Still awaiting the parts, I've had my original supplier in the UK on the case and he's also ordered what's needed.

I am not expecting to get behind the wheel until October!

I can't tell you how frustrating this whole thing has been.

Rob

 

Rob,
Just to let you know, I've had my Chevy SSr in the shop here in San Diego for two months, also. It was from a light front-end accident. GM must have shut down building parts during the bankrupcy and parts are scarce. This is changing, but the front fender would not be delivered until January 2010. So, I had them repair it. A Corvette is also in the same shop awaiting a part that won't be available until March. The lady who handles my car said this is very unusual and has only happened since the BK. She said her contact at Chevy parts was telling her things are getting better and returning to normal. Regardless, when I pick the car up today they will still be waiting for the inner fender liner to come in, which will be another week or so.