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leomd
Member
Date registered: Nov 2013
Location: Miami, Florida
Vehicle(s): 2002 G500-Bessie
Posts: 33
| 2003 G55 Intermittent ESP/BRAKE light
Im having an issue trying to diagnose a intermittent ESP/Brake light warning. I have replaced the stop lamp swith at the pedal which solved my locking transmission while in park issue but I still seem to get an intermittant ESP/BRAKE warning when driving. It usually clears itslef upon restart and will sometime occur at the beginning of a drive or until the end or never at all. It feels like the warning happens more often during city driving rather than highway driving.
The other night I went through the entire history of the car and saw 2 intersting invoice details during 2010 from the previous owner:
10/21/2010 - ESP Light on - C1201-004 a7/7s1 BAS Release Switch Plausability. (Indy mechanic diagnosis invoice with no repair)
12/30/2010 - Perfomed SDS Test: found code C1204-004 Perf Guide Test, found stop lamp switch inside brake boster to be faulty. cust declined work at this time. (From MB FLL dealership)
When I took ownership of the car in January 2014 I also cleared a OBD2 code that indicated the rear left speed sensor was in error, but since clearing this it has not come back.
Im not sure how to move forward on this as it could either be a speed sensor or brake issue - any ideas thought would be greatly appreciated. Thanks in advance for any help or ideas.
Leo
Edited by leomd 9/10/2014 5:26 PM
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djdinaz
Extreme Veteran
Date registered: Jun 2007
Location: Arizona
Vehicle(s): 03 G55
Posts: 439
| RE: 2003 G55 Intermittent ESP/BRAKE light
I'd suggest finding an indy w/ an SDS (Star Diagnostic System) and have them run through the diagnostic tests for the ABS control units.
The two errors, both brake related, center around the sensors and control units on (and in) the brake booster itself.
The A7/7s1 release switch is buried inside the brake booster. It works in conjunction w/ the BAS control unit, and the A7/7y1 solenoid valve. In an emergency stop, the BAS solenoid valve A7/7y1 opens, allowing immediate full boost of braking power.
If it is indeed the A7/7s1 (or 7y1), then your brake booster needs to be changed. The part, though not unique to the G, is used on the SL's as well, and is very pricey (1K+), which is why you'd want to at least have an indy validate that the problem is definitely that switch before undertaking the endeavor.
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CAO
Date registered: Nov 2007
Location: Ellensburg, WA
Vehicle(s): '13 G550 (G #5)
| RE: 2003 G55 Intermittent ESP/BRAKE light
I had the same issue on a 2002, ended up being being the directional unit in the steering column. Not the only item it could be, but one possibility.
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leomd
Member
Date registered: Nov 2013
Location: Miami, Florida
Vehicle(s): 2002 G500-Bessie
Posts: 33
| RE: 2003 G55 Intermittent ESP/BRAKE light
Thanks DJ for that excellent description and graphic - very helpful indeed.
I will purchase a Star diagnostic system from ebay since I have two of these beasts sitting in my garage. Most of the decent local Indy's here in Miami charge rates close to that of dealerships.
I was fearing the booster would have to be replaced, and with my luck that is most likely the culprit as indicated from the prior tests. Either way you are right I need to electronically diagnose to make certain then buy a new booster and and swap it out.
Do you think dirty barke fluid could be causing the issue? Would it be worth the expense to flush the system before embarking on replacement? My brake fluid has not been changed since 2009 (1 year prior to when the PO had those errors checked end of 2010). I have noticed the intermmitent warning is becoming more frequent with time.
Thanks again for the great help. |
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| RE: 2003 G55 Intermittent ESP/BRAKE light
leomd - 9/13/2014 11:04 AM
I will purchase a Star diagnostic system from ebay since I have two of these beasts sitting in my garage.
Just be forewarned if one of your potential sources has an AmandaHall email address. I was scammed to the tune of a couple of hundred bucks by her. Ymmv, but be forewarned. |
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djdinaz
Extreme Veteran
Date registered: Jun 2007
Location: Arizona
Vehicle(s): 03 G55
Posts: 439
| RE: 2003 G55 Intermittent ESP/BRAKE light
I don't think dirty fluid would cause the issue.. but.. a brake fluid change never hurts.
Another thing to look at would be dirty wiring. If how you describe it as being intermittent, I'd first clean/reseat/check the wiring harness that plugs into the booster. It's exposed to the elements under the hood, looking at A7/7 under my relatively clean engine bay, it looks dirty and exposed.
That connector is a 6 wire plug, with pins 1,5, & 2 running to A7/7s1 (solenoid) and 3 & 4 to A7/7y1.
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leomd
Member
Date registered: Nov 2013
Location: Miami, Florida
Vehicle(s): 2002 G500-Bessie
Posts: 33
| RE: 2003 G55 Intermittent ESP/BRAKE light
Excellent idea - will do a clean/check/reseat today. I cant get over how clean your engine/bay is - I guess I have some engine detailing ahead of me. Also, my fluid is many shades darker than yours - looks like a fluid change will be next :-)
Thanks Dutch on the ebay headsup - I will do my homework before buying.
Thanks guys!
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djdinaz
Extreme Veteran
Date registered: Jun 2007
Location: Arizona
Vehicle(s): 03 G55
Posts: 439
| RE: 2003 G55 Intermittent ESP/BRAKE light
I cant get over how clean your engine/bay is
I wish mine was that clean too.
That pic is from MB's WEB ETM (Star Finder).. more than likely from a truck that's never been driven. |
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leomd
Member
Date registered: Nov 2013
Location: Miami, Florida
Vehicle(s): 2002 G500-Bessie
Posts: 33
| RE: 2003 G55 Intermittent ESP/BRAKE light
SUCCESS!
As the weeks went by the error light came on almost all the time, especially after first hitting the brake pedal upon start-up. Upon seeing that the code was realted to braking I realized 100% it was not a speed sensor and most definetly related to an electric swtich.
I eneded up not purchasing a diagnotic system or having it diagnosed as I hate to spend unnecessary money and am generally cheap :-). Since I had studied the PO's records that showed that 2 independant visits found an error in the microswitch of the booster I decided it was fair to assume that the Booster was the culprit.
And so I began the journey to find a replacement booster at a reasonable cost. I found that OEM MB part has a list price of $ 1,420.00 and was still priced at $ 994.00 at my favorite online discount MB dealer Husker Automotive. I found reconditioned units online for around $350.00 + core deposit. I still was not happy with those prices so I did further research and found a OEM great condition low mileage part from a 2001 SL. I made an offer to the seller on ebay and managed to get the part for only $60.00 - woo hoo score!
The part was clean, looked almost new and installed in about 30 minutes. Although I havent had a chance to fully bleed the system (had to crack open the lines to remove master cylinder) I took it for a short test drive and the error codes are all GONE. Suprisingly the brakes work very well considering there is air in the sytem. As suspected one of the microswitches in the booster must have gone bad. Im not sure which feeling is better, having my G55 fixed or having it fixed for only $60 when a dealership would have charged me upwards of $3000!
Part numbers for anyone going through this:
The latest current part number for the booster is A005-430-00-930. This is same as below #'s but supersedes them.
The unit I pulled out of my 03 G55 had part number A005-430-36-30 and was labeled as being made by TRW.
The unit I was sent from a 2001 SL had part number on it A004-430-42-30 and is made/labeled by Lucas.
Big special THANK YOU to djdinaz for pointing out the two booster microswtiches and also giving me the idea of chasing down an SL part! As always this forum is an invaluable asset.
Edited by leomd 10/16/2014 1:25 PM
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H1LM002G55
Expert
Date registered: Mar 2010
Location: S Florida / Geneva / Jeddah
Vehicle(s): 500 GE, G55, LM002, H1
Posts: 1796
| Re: 2003 G55 Intermittent ESP/BRAKE light
Had the ESP Warning issue on my 2003 G55 in the past also. It would usually occur when taking a curve on an on-ramp to get on a highway. Seems to be pretty common on early MBUSA trucks...(2002-2005 models). |
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