No power brakes on startup (cold)? SS
05-13-2008, 01:40 AM
#1
Member
Thread Starter
Join Date: 03-30-2008
Location: Canada
Posts: 78
No power brakes on startup (cold)? SS
A month into HHR SS ownership, and having an issue with my brakes.
Started about two weeks in..when starting it (garaged) in the morning (or after work when its been sitting for 8h), the brakes took more then a little pressing down on the pedal to stop. Backing up out of the driveway, or out of a parking spot, it would take pressing to the floor to get the car to stop. Basically, like having no power brakes. Its pretty dangerous to be expecting brakes to grab if you have to stop suddenly, then the panic of having to press down again almost to the floor when just simplay backing up slowly, as by then it may be too late. Going forward at slow speeds in that scenario, same thing. Basically, its like the car doesn't have power brakes after a "cold" startup, for a short period.
As soon as the car gets up to driving speed even 10-15sec later, it seems to have no issue and "power" seems to be restored. Also, if I stop to run into a store for 10 mins and come back, there's no issue. No other brake issues from what I can tell in normal driving conditions at this point. No odd noises or creaking associated, just brakes that don't feel like thay have any power to them.
It was actually at the dealer to get the road rash from the delivery truck fixed (half assed, btw) paint protection, rust proofing etc etc in last week, and I got an oil change and told them about this issue.
They supposedly had a TSB (#08-05-22-001) on it for an EBCM reflash and they did that. Bulletin said that the pedal feel like this is "normal" (? can't believe having to hammer on the pedal for the car to stop is "normal" feel) and the flash "should improve feel" That was a few days ago and the issue is still there as of today.
Not keen on rushing back to the dealer with it, but will likely will soon to get them to check it out. I'm worried that if its an issue with some part of the system now, it could grow into something worse and have something fail at full speed, without notice, down the road. At worst, this still isn't fixed and if me and my wife have to stop quickly when backing up, this is going to fail us.
Before another dealer trip, just thought I'd see if anyone else has had similar symptoms. It is power brakes? In 2004, the Avalanche I had (I didn't have this issue personally) had a recall of something similar, where the vacuum line could get pinched and not provide adequate pressure for the brakes, thus the "loss of power", so maybe its similar. I guess it could be the traction control module, but the wheels are barely moving and hardly slipping, which would cause that to kick in....and in that case it should do it everytime when moving slow, not just on cold startups, right? I haven't seen my sepcific issue on a search of the boards, but just checking...as the dealer thought they identified the problem, but no dice it seems.
Started about two weeks in..when starting it (garaged) in the morning (or after work when its been sitting for 8h), the brakes took more then a little pressing down on the pedal to stop. Backing up out of the driveway, or out of a parking spot, it would take pressing to the floor to get the car to stop. Basically, like having no power brakes. Its pretty dangerous to be expecting brakes to grab if you have to stop suddenly, then the panic of having to press down again almost to the floor when just simplay backing up slowly, as by then it may be too late. Going forward at slow speeds in that scenario, same thing. Basically, its like the car doesn't have power brakes after a "cold" startup, for a short period.
As soon as the car gets up to driving speed even 10-15sec later, it seems to have no issue and "power" seems to be restored. Also, if I stop to run into a store for 10 mins and come back, there's no issue. No other brake issues from what I can tell in normal driving conditions at this point. No odd noises or creaking associated, just brakes that don't feel like thay have any power to them.
It was actually at the dealer to get the road rash from the delivery truck fixed (half assed, btw) paint protection, rust proofing etc etc in last week, and I got an oil change and told them about this issue.
They supposedly had a TSB (#08-05-22-001) on it for an EBCM reflash and they did that. Bulletin said that the pedal feel like this is "normal" (? can't believe having to hammer on the pedal for the car to stop is "normal" feel) and the flash "should improve feel" That was a few days ago and the issue is still there as of today.
Not keen on rushing back to the dealer with it, but will likely will soon to get them to check it out. I'm worried that if its an issue with some part of the system now, it could grow into something worse and have something fail at full speed, without notice, down the road. At worst, this still isn't fixed and if me and my wife have to stop quickly when backing up, this is going to fail us.
Before another dealer trip, just thought I'd see if anyone else has had similar symptoms. It is power brakes? In 2004, the Avalanche I had (I didn't have this issue personally) had a recall of something similar, where the vacuum line could get pinched and not provide adequate pressure for the brakes, thus the "loss of power", so maybe its similar. I guess it could be the traction control module, but the wheels are barely moving and hardly slipping, which would cause that to kick in....and in that case it should do it everytime when moving slow, not just on cold startups, right? I haven't seen my sepcific issue on a search of the boards, but just checking...as the dealer thought they identified the problem, but no dice it seems.
05-13-2008, 06:39 AM
#2
Member
Join Date: 04-08-2008
Location: Asheville NC
Posts: 44
I'm having a similar problem with my SS with only 2k miles. When I back out sometimes I can hear the left front caliper "clunk" like the pads were stuck to the rotor (this has happened maybe 4 times). Emergency brake was not on and works on the rear only anyway. The pedal loss problem has only happened a couple times now but when it does the pedal goes almost all the way to the floor. I immediately put it in park and pump the brakes. Eventually the pressure returns and everything is "normal". It does make a sound that's hard to describe while pumping the brakes. Kind of like the pads squeezing the rotors and jumping around? The only two times this has happened was after it sat over night. Otherwise the braking performance has been excellent. I did check around the calipers for brake fluid leaks and checked the level of the fluid, everything looks good. 
05-13-2008, 06:45 AM
#3
Banned
Join Date: 10-24-2006
Location: The Show-Me State
Posts: 1,761
Most GM cars I've owned have an ABS check that happens in the first few seconds of startup that pulses the system for a second, but nothing where the pedal has gone to the floor for the first few minutes. Sounds like it may be an ABS system problem and you should have it looked into under warranty.
Why on Earth people still buy into paint protection and rustproofing schemes I'll never know. You're better off without them on modern cars.
Why on Earth people still buy into paint protection and rustproofing schemes I'll never know. You're better off without them on modern cars.
05-13-2008, 06:59 AM
#4
Senior Member
Join Date: 03-28-2008
Location: Oshawa
Posts: 1,115
Not trying to buzz the thread, but canadians have salt poured on the roads in the winter. We need the extra protection!!
Good luck with the brake problem. Sounds pretty dangerous. I wonder if ChevMgr has any info on this.:twothumbs
Good luck with the brake problem. Sounds pretty dangerous. I wonder if ChevMgr has any info on this.:twothumbs
05-13-2008, 01:34 PM
#5
Member
Thread Starter
Join Date: 03-30-2008
Location: Canada
Posts: 78
This is a black car, a daily driver car which we're keeping as the second car for as long as it runs, so worth the extra peice of mind and coverage.
I am more then weary of dealer schemes that are over priced..but this is the first new vehcile I've purchased outright (after 5 GM leases in past 10 years). With 0% financing for 5 years I could throw everything into the purchase, and, with the sale I got this off of the dealer was having, among other things, paid "half" off all of the protection/undercoating services to boot.
Also opted for the vinyl applications to the front end.
As for my issue, this morning, I let the car idle for an extra 20 seconds, and then pumped the brakes a bit before backing out...seemed to work. Maybe it is the vaccuum hose?
05-13-2008, 01:40 PM
#6
Founding Member
Join Date: 11-23-2007
Location: Texas
Posts: 8,210
Here is a copy of the bulletin:
08-05-22-001: Pedal Noise/Buzz, Extra Effort Needed to Depress Brake Pedal After Vehicle Has Not Been Driven for Extended Period of Time (Reprogram Electronic Brake Control Mdoule (EBCM)) - (Mar 18, 2008)
Subject: Pedal Noise/Buzz, Extra Effort Needed to Depress Brake Pedal After Vehicle Has Not Been Driven for Extended Period of Time (Reprogram Electronic Brake Control Module (EBCM))
Models: 2008 Chevrolet HHR SS
--------------------------------------------------------------------------------
Condition
Some customers may comment that after their vehicle has not been operated for an extended period of time, there may be a noise or buzz coming from the brake pedal or extra effort may be needed to depress the brake pedal.
Correction
Important: The following Optimized Hydraulic Brake (OHB) characteristics are considered to be normal and no mechanical parts should be replaced in an effort to change the operation of the system:
• Ratchet sound coming from the brake system during OHB activation.
• Brake pedal movement or pulsation when the OHB is active.
• Increased brake pedal effort under low brake booster vacuum.
• Change in brake pedal effort when OHB is active.
• Frequent brake stops may result in OHB activation.
• High altitude driving may result in OHB activation.
Refer to Corporate Bulletin Number 07-05-22-002 for further information on Optimized Hydraulic Boost Brake System Characteristics.
DO NOT replace the brake vacuum booster, brake vacuum sensor, EBCM or ABS module for this condition.
An Electronic Brake Control Module (EBCM) calibration was released that may reduce the effort the customer feels when depressing the brake pedal on a car that has not been operated for an extended period of time. Reprogram the EBCM with updated calibration files using the TIS2WEB Service Programming System (SPS) application. As always, make sure your Tech 2® is updated with the latest software version.
08-05-22-001: Pedal Noise/Buzz, Extra Effort Needed to Depress Brake Pedal After Vehicle Has Not Been Driven for Extended Period of Time (Reprogram Electronic Brake Control Mdoule (EBCM)) - (Mar 18, 2008)
Subject: Pedal Noise/Buzz, Extra Effort Needed to Depress Brake Pedal After Vehicle Has Not Been Driven for Extended Period of Time (Reprogram Electronic Brake Control Module (EBCM))
Models: 2008 Chevrolet HHR SS
--------------------------------------------------------------------------------
Condition
Some customers may comment that after their vehicle has not been operated for an extended period of time, there may be a noise or buzz coming from the brake pedal or extra effort may be needed to depress the brake pedal.
Correction
Important: The following Optimized Hydraulic Brake (OHB) characteristics are considered to be normal and no mechanical parts should be replaced in an effort to change the operation of the system:
• Ratchet sound coming from the brake system during OHB activation.
• Brake pedal movement or pulsation when the OHB is active.
• Increased brake pedal effort under low brake booster vacuum.
• Change in brake pedal effort when OHB is active.
• Frequent brake stops may result in OHB activation.
• High altitude driving may result in OHB activation.
Refer to Corporate Bulletin Number 07-05-22-002 for further information on Optimized Hydraulic Boost Brake System Characteristics.
DO NOT replace the brake vacuum booster, brake vacuum sensor, EBCM or ABS module for this condition.
An Electronic Brake Control Module (EBCM) calibration was released that may reduce the effort the customer feels when depressing the brake pedal on a car that has not been operated for an extended period of time. Reprogram the EBCM with updated calibration files using the TIS2WEB Service Programming System (SPS) application. As always, make sure your Tech 2® is updated with the latest software version.
Last edited by ChevyMgr; 05-13-2008 at 02:01 PM. Reason: correction
05-13-2008, 02:05 PM
#7
Founding Member
Join Date: 11-23-2007
Location: Texas
Posts: 8,210
Here is the other bulletin mention in the prior post?
#07-05-22-002: Information on Optimized Hydraulic Boost Brake System Characteristics - (Jun 4, 2007)
Subject: Information on Optimized Hydraulic Boost Brake System Characteristics
Models: 2008 Pontiac Solstice GXP
2008 Saturn Sky Redline
2008 Opel GT
with 2.0L Engine (VIN X - RPO LNF)
--------------------------------------------------------------------------------
The Optimized Hydraulic Boost (OHB) is a standard feature, included with all 2008 vehicles equipped with the 2.0L (RPO LNF) engine). OHB assists brake operation under low engine vacuum conditions using the ABS system.
If your vehicle has Electronic Stability Control (ESC) and the 2.0L turbocharged engine, it will also have a hydraulic brake boost feature which supplements the power brake system to maintain consistent brake performance under conditions of low brake booster vacuum utilizing the ABS system.
Important: Increased brake pedal effort due to low brake booster vacuum conditions may exist during;
• The initial cold engine start up and the first few brake applies.
• When the vehicle has been parked for extended periods and/or at higher altitudes and restarted.
• Any time the vehicle is started up after a brake booster has been completely bled down (no stored vacuum).
The OHB functions are controlled by the Electronic Stability Control (ESC) Module. The ESC module determines when to activate the OHB.
The following OHB characteristics are considered to be normal:
• Increased brake pedal effort under low brake booster vacuum.
• Change in brake pedal effort when OHB is active.
• Ratchet sound coming from the brake system during OHB activation.
• Frequent brake stops may result in OHB activation.
• High altitude driving may result in OHB activation.
• Brake pedal movement or pulsation when the OHB is active.
Some customers may bring their vehicle back to the dealership commenting on any or all of the above characteristics . The customer may experience brake pedal movement or pulsation accompanied by a change in brake pedal effort when the OHB is active.
Important: Do not attempt to repair or replace any parts for what is considered normal operation of the OHB.
If a condition should exist in which you might not be receiving the intended brake boost, the SVC BRAKE SYSTEM message may be displayed on the DIC.
#07-05-22-002: Information on Optimized Hydraulic Boost Brake System Characteristics - (Jun 4, 2007)
Subject: Information on Optimized Hydraulic Boost Brake System Characteristics
Models: 2008 Pontiac Solstice GXP
2008 Saturn Sky Redline
2008 Opel GT
with 2.0L Engine (VIN X - RPO LNF)
--------------------------------------------------------------------------------
The Optimized Hydraulic Boost (OHB) is a standard feature, included with all 2008 vehicles equipped with the 2.0L (RPO LNF) engine). OHB assists brake operation under low engine vacuum conditions using the ABS system.
If your vehicle has Electronic Stability Control (ESC) and the 2.0L turbocharged engine, it will also have a hydraulic brake boost feature which supplements the power brake system to maintain consistent brake performance under conditions of low brake booster vacuum utilizing the ABS system.
Important: Increased brake pedal effort due to low brake booster vacuum conditions may exist during;
• The initial cold engine start up and the first few brake applies.
• When the vehicle has been parked for extended periods and/or at higher altitudes and restarted.
• Any time the vehicle is started up after a brake booster has been completely bled down (no stored vacuum).
The OHB functions are controlled by the Electronic Stability Control (ESC) Module. The ESC module determines when to activate the OHB.
The following OHB characteristics are considered to be normal:
• Increased brake pedal effort under low brake booster vacuum.
• Change in brake pedal effort when OHB is active.
• Ratchet sound coming from the brake system during OHB activation.
• Frequent brake stops may result in OHB activation.
• High altitude driving may result in OHB activation.
• Brake pedal movement or pulsation when the OHB is active.
Some customers may bring their vehicle back to the dealership commenting on any or all of the above characteristics . The customer may experience brake pedal movement or pulsation accompanied by a change in brake pedal effort when the OHB is active.
Important: Do not attempt to repair or replace any parts for what is considered normal operation of the OHB.
If a condition should exist in which you might not be receiving the intended brake boost, the SVC BRAKE SYSTEM message may be displayed on the DIC.
05-13-2008, 04:33 PM
#9
Senior Member
Join Date: 03-31-2008
Location: So Cal
Posts: 179
It has happened to me too. I know it is low vacuum. In warm up mode the car is diling higher and the turbo is keeping vacuum under ~10psi. This is obviously not optimal for the brake booster and creates this issue. I think there is a reserve/check valve for the vacuum but it may get depleted overnight. Anyone who ever had PDB in a muscle car and put a large lift close LSA bumpstick knows this issue all too well.
