This is the most recent publication from GM-Release dated 5-1-08, still no hard part replacement.
05/01/2008 GM Training Magazine - SPRING EDITION
05/01/2008 Pedal Noise/Buzz, Extra Effort Needed to Depress Brake Pedal After Vehicles Has Not Been Driven for Extended Period Revised
05/01/2008 Bulletin GMP08-076 - GM Vehicle Care R134a Refrigerant (Part Number 12356150)
SERVICE - PONTIAC DEALERS / SATURN RETAILERS
Subject: Pedal Noise/Buzz, Extra Effort Needed to Depress Brake Pedal After Vehicles Has Not Been Driven for Extended Period Revised
Message #: VSS20081471-01
Corporate Bulletin Number 07-05-25-007A is currently available in SI.
Pedal Noise/Buzz, Extra Effort Needed to Depress Brake Pedal After Vehicle Has Not Been Driven for Extended Period of Time (Reprogram EBCM and ECM)
Models: 2008 Pontiac Solstice GXP
2008 Saturn SKY Redline
2008 Daewoo G2X
Attention: This bulletin will be released in two versions. The first release will be for vehicles equipped with an automatic transmission and built prior to the VIN breakpoints listed below. The second version of this bulletin will be released in May 2008 and will include all vehicles equipped with a manual transmission.
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This bulletin is being revised to provide system description and an updated correction. Please discard Corporate Bulletin Number 07-05-25-007 (Section 05 — Brakes).
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Model VIN Breakpoint
Saturn 8Y129355
Pontiac 8Y129363
Daewoo All Vehicles
Please make a copy of this bulletin and give it to your customer for future reference.
System Description
The 2008 Pontiac Solstice GXP, Saturn SKY Redline, and Daewoo G2X are performance vehicles that come equipped with the 2.0L (RPO LNF) engine and an advanced performance braking system called Optimized Hydraulic Boost (OHB). The OHB brake system utilizes the Anti-Lock Brake System (ABS) to assist vehicle braking in low brake vacuum conditions.
The brake systems on these vehicles use engine vacuum to assist the power brake system during most brake applications. The OHB system supplements the power assist brake system when there is low engine vacuum, such as when the engine is initially started after an extended period of no operation or while operating in high altitude.
Condition
Some customers may comment on one or more of the following brake system characteristics:
• Increased brake pedal effort due to low brake booster vacuum conditions that may occur after the vehicle has not been operated for an extended period of time and/or at higher altitudes and restarted.
• Brake pedal movement or pulsation accompanied by a ratchet sound coming from the brake system during OHB activation when braking.
Correction
Reprogram the ECM with an updated engine calibration. This new service calibration will increase engine vacuum when the vehicle is initially started.
Reprogram the EBCM with an updated brake calibration. This programming event will return the module to its original state if it was previously updated for this condition.
These calibrations will be available as an EBCM/ECM programming sequence event. From the controller list, select "EBCM/ECM Sequential Program."
Important:
• Allowing the engine to idle for a period of time after the engine is started will help increase the vacuum for the power assist brake system.
• Somewhat increased brake pedal effort and/or pulsation may still be experienced during cold engine start and braking with this revised calibration.
• If the SVC BRAKE SYSTEM message is displayed on the DIC. The brake system must be inspected for any faults in the system.
Refer to the Owner Manual (page 4-4 for the Pontiac Solstice or Saturn SKY) for additional information on this brake system operation.
Released 5-1-08- Brake update on Redlines/GXP - Saturn Sky Forum
Linear Mode
