Brake & Interlock Warning Lights coming on.
03-22-2003, 12:24 PM
#1
1st Gear
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Join Date: Mar 2003
Location: Dartmouth Nova Scotia
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Brake & Interlock Warning Lights coming on.
Hello
I have been searching the web for clues on why my Brake Pressure /
Brake Fluid warning light and the Interlock warning lights will come on.
My car is a 1991 C4 with 70,000kms on it and I first noticed the lights
coming on when I had installed a new pair of tires on the rear of the
car which I purchased from a friend at the end of the season a year and
a half ago. He had only about 500km's on the tires but my front tires
were down to the wear bars. I thought the light came on because of the
difference in wear between the 2 pairs of tires but nice it was late in
the year and the car was going away for storage I did not worry about
it.
Last spring I put a new set of tires on the front and after an early
puncture of a rear tire I replaced the rear 2 Potenza S3's to match the
front.
During the warm summer months the light would not come on but once
Sept. came around the lights would come on again.
Sometimes I could be just sitting and the lights would come on or I
could be driving along and an hour or so later the lights would come on.
No warning buzzer , but the acknowledge light would come on.
I had the car in with the lights on to the dealer and he would hook up
his hand held to see if any faults were in but nothing concerning my
lights. They then re-routed my grounding strap and again no help.
Do you have any ideas for me as they would be much appreciated. Thank
you . - Jody Crane
I have been searching the web for clues on why my Brake Pressure /
Brake Fluid warning light and the Interlock warning lights will come on.
My car is a 1991 C4 with 70,000kms on it and I first noticed the lights
coming on when I had installed a new pair of tires on the rear of the
car which I purchased from a friend at the end of the season a year and
a half ago. He had only about 500km's on the tires but my front tires
were down to the wear bars. I thought the light came on because of the
difference in wear between the 2 pairs of tires but nice it was late in
the year and the car was going away for storage I did not worry about
it.
Last spring I put a new set of tires on the front and after an early
puncture of a rear tire I replaced the rear 2 Potenza S3's to match the
front.
During the warm summer months the light would not come on but once
Sept. came around the lights would come on again.
Sometimes I could be just sitting and the lights would come on or I
could be driving along and an hour or so later the lights would come on.
No warning buzzer , but the acknowledge light would come on.
I had the car in with the lights on to the dealer and he would hook up
his hand held to see if any faults were in but nothing concerning my
lights. They then re-routed my grounding strap and again no help.
Do you have any ideas for me as they would be much appreciated. Thank
you . - Jody Crane
03-23-2003, 09:47 AM
#2
Addict
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Lead Rennlist
Technical Advisor
Rennlist
Lifetime Member
Dear Jody,
Firstly there are a number of places to check out this problem. The rennlist technical section has quite a document on the opeation of this system. This question and fixes are found in the archives.
The first warning lights combination you have is directly related to brake boost pressure. You are loosing pressure which means it is dropping below 102 bar OR your pressure switch on the brake boost hydraulic pump is playing up.
The second warning lights combination you mention (no warn horn) means your brake fluid level is incorrect.
So the first job is to top up the brake fluid level. This cannot be done by just looking at the fluid level. You must start the the engine (to avoid battery drain) and let the hydraulic pump run until is cuts out. This is the time you check the fluid level.
If topping the fluid up does not work you need to check the connectors of the brake fluid level sensor on the brake fluid reservoir.
This is not a grounding issue. The master warn and the warn horn are telling you that the system warn priority system is activated.
Summary:
Warn lights tell you there is problem. With the warn horn it means a serious problem.
I would also ask you when you last checked your brake fluid level? When did you last change the fluid? Have you looked for a brake fluid leak? I would recommend you check for evidence of brake fluid loss in the front area of the luggage compartment.
Ciao,
Adrian
911C4
Firstly there are a number of places to check out this problem. The rennlist technical section has quite a document on the opeation of this system. This question and fixes are found in the archives.
The first warning lights combination you have is directly related to brake boost pressure. You are loosing pressure which means it is dropping below 102 bar OR your pressure switch on the brake boost hydraulic pump is playing up.
The second warning lights combination you mention (no warn horn) means your brake fluid level is incorrect.
So the first job is to top up the brake fluid level. This cannot be done by just looking at the fluid level. You must start the the engine (to avoid battery drain) and let the hydraulic pump run until is cuts out. This is the time you check the fluid level.
If topping the fluid up does not work you need to check the connectors of the brake fluid level sensor on the brake fluid reservoir.
This is not a grounding issue. The master warn and the warn horn are telling you that the system warn priority system is activated.
Summary:
Warn lights tell you there is problem. With the warn horn it means a serious problem.
I would also ask you when you last checked your brake fluid level? When did you last change the fluid? Have you looked for a brake fluid leak? I would recommend you check for evidence of brake fluid loss in the front area of the luggage compartment.
Ciao,
Adrian
911C4
