BRAKE light and Anti lock light have lit up, where to look first?

comquat1 · 31 October 2017

My car has sat for a couple weeks now not being driven and today when I took it to run an errand I noticed the brake light was lit up on the dash. I didn't notice it until I had pulled out of my cul de sac and once I got about 1/2 a mile down the road the anti lock brake light went on. The whole time the car drove fine and braked but clearly something isn't right. What's the first thing to start looking at? Anyone seen this before?

jwmelvin · 1 November 2017

Start with pulling the ABS code by shorting the service connector.

comquat1 · 1 November 2017

jwmelvin said:
Start with pulling the ABS code by shorting the service connector.

How do you do that??? How do you read codes on these pre-odbII cars?

jwmelvin · 1 November 2017

comquat1 said:
How do you do that??? How do you read codes on these pre-odbII cars?

The service connector is the blue two-pin connector just above the passenger’s feet. Short the two pins with an unbent paper clip or short piece of wire. Then turn the ignition on and watch the dash lights. The service manual helps you decode them. The ABS light should report ABS codes (I’ve only owned NA2 cars but I believe all this applies to OBD1).

comquat1 · 1 November 2017

jwmelvin said:
The service connector is the blue two-pin connector just above the passenger’s feet. Short the two pins with an unbent paper clip or short piece of wire. Then turn the ignition on and watch the dash lights. The service manual helps you decode them. The ABS light should report ABS codes (I’ve only owned NA2 cars but I believe all this applies to OBD1).

Thanks, I'll try to get to that in the next couple days.

comquat1 · 1 November 2017

Talked to service writer this morning. He’s thinking it may be a wheel speed sensor. I can’t get it in for a week so I have a little time to see if I can diagnose this myself. Any help on how to see if you have a faulty speed sensor? I know enough to only be dangerous.

Sent from my iPhone using Tapatalk

Arkaid · 1 November 2017

comquat1 said:
Talked to service writer this morning. He’s thinking it may be a wheel speed sensor. I can’t get it in for a week so I have a little time to see if I can diagnose this myself. Any help on how to see if you have a faulty speed sensor? I know enough to only be dangerous.

Sent from my iPhone using Tapatalk

As jwmelvin said, short the pins on the service connector by bridging them together and see what codes pop up. Each corner WSS has a different code. Larry highlights them in the below:

http://www.nsxprime.com/forum/showt...Lights-Come-On-Together?highlight=TCFC Signal

Though I thought that usually if it was a WSS, you'd be seeing the TCS and ABS lights as Hugh had seen. In any case, check the codes and see what shows up.

Larry Bastanza · 1 November 2017

As mentioned above a wheel speed sensor failure would also light the TCS light, both systems use the same sensors. I am thinking your ABS system needs a flush and bleed. Did you hear the ABS pump running for 2 minutes?

nsxspdfreak · 1 November 2017

Here is a link to instructions on reading codes. http://www.nsxcb.co.uk/showthread.php?9229-How-to-read-the-error-code

Here are the codes for the ABS light.
 1 - ABS pump motor over-run
1 2 ABS pump motor
1 3 high pressure leakage
1 4 pressure switch
1 8 high pressure system
2 1 parking brake
3 1 pulser RF
3 2 pulser LF
3 4 pulser RR
3 8 pulser LR
3 12 different diameter tires
4 1 wheel sensor RF
4 2 wheel sensor LF
4 4 wheel sensor RR
4 8 wheel sensor LR
5 - rear wheel lock - R/L
5 4 rear wheel lock - R
5 8 rear wheel lock - L
6 - fail-safe relay - F/R
6 1 fail-safe relay - F
6 4 fail-safe relay - R
7 1 solenoid - RF
7 2 solenoid - LF
7 4 solenoid - R
8 1 ABS function
8 2 CPU comparison
8 4 IC self-check

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w

unctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w

oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w

ontGrowAutofit/> <w:SplitPgBreakAndParaMark/> <w:EnableOpenTypeKerning/> <w

ontFlipMirrorIndents/> <w:OverrideTableStyleHps/> </w:Compatibility> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]-->

Old Guy · 1 November 2017

comquat1 said:
My car has sat for a couple weeks now not being driven and today when I took it to run an errand I noticed the brake light was lit up on the dash. I didn't notice it until I had pulled out of my cul de sac and once I got about 1/2 a mile down the road the anti lock brake light went on. The whole time the car drove fine and braked but clearly something isn't right. What's the first thing to start looking at? Anyone seen this before?

So, brake system warning light lit up and ABS light on? As far as I can tell, there are only two things that cause the brake system warning light to come on. The parking brake is applied or the brake fluid is low. If the parking brake is applied (or the ABS 'thinks' that the parking brake is applied because of a ground fault) and you drive the car for more than 30 seconds this will cause the ABS system to generate an error code. If you retrieve the ABS error code and you get a code 2* that confirms that the issue is originating with the parking brake. Since the brake warning light was on and the ABS light came on about 1/2 mile later I suggest that the problem could be:

1 - the parking brake is on or partially applied or the parking brake switch is out of adjustment.
2 - the brake reservoir fluid switch appears to be connected in parallel with the parking brake switch so I think low fluid in the brake reservoir could trigger exactly the same symptoms.
3 - you have a chaffed wire in the brake warning circuit that is grounding and causing the warning lights to come on.

Pull the error code to confirm that it is code 2*. Then check the brake reservoir level first just because it is the easiest thing to check. After that look into the parking brake switch. With luck it will not be a wiring problem.

* Nsxspdfreak provided an ABS code list that identifies a different code (2-1) for the parking brake. I got my error code from the 1991 service manual which just lists a main code of 2 and no sub code. His codes may be from a later model year or there might be an error in the 1991 service manual or I just don't know how to read. Larry B might be able to confirm the correct error code for the 1991 system - parking brake error.

comquat1 · 1 November 2017

Larry Bastanza said:
As mentioned above a wheel speed sensor failure would also light the TCS light, both systems use the same sensors. I am thinking your ABS system needs a flush and bleed. Did you hear the ABS pump running for 2 minutes?

I believe my traction control isn’t connected. I had my abs rebuilt a year ago with the seal kit that was offered here on prime.

Is this the plug I’m looking for to short out?

Sent from my iPhone using Tapatalk

comquat1 · 1 November 2017

One additional note, call me crazy on this but I have felt my parking brake had a lot of play before it would click initially as I pulled it up. For example I could be driving and lift the handle just a little bit and I could make the brake light go on. When I would do this I swear I hear an “electrical click” when it would go on. I now do no hear it when I slightly pull up I the handle. Is that because the light is always engaged? Just throwing more info onto the burn pile, no idea if it’s relevant. I’m going to see if I can pull that code tonight. I’m assuming in my pic above I short out the male plug?

Sent from my iPhone using Tapatalk

jwmelvin · 1 November 2017

[MENTION=6369]comquat1[/MENTION] yes that’s the plug

comquat1 · 1 November 2017

https://youtu.be/KeuP8XkOPQg

Sent from my iPhone using Tapatalk

comquat1 · 1 November 2017

Looks like 3 long blinks and 6 short?

Sent from my iPhone using Tapatalk

comquat1 · 1 November 2017

Did this a second time and got the same blinks. https://youtu.be/-2LGZgtk7C4

Sent from my iPhone using Tapatalk

jwmelvin · 2 November 2017

That’s your CEL blinking a 3-6. The ABS light appears to blink a 2.

comquat1 · 2 November 2017

jwmelvin said:
That’s your CEL blinking a 3-6. The ABS light appears to blink a 2.

I missed that.... goodness sakes... So it would be pointing at parking brake?

jwmelvin · 2 November 2017

comquat1 said:
I missed that.... goodness sakes... So it would be pointing at parking brake?

Yes, looks that way. I’d pull the center console to get access to the connector for the parking-brake switch and see if you can deal with it there.

jwmelvin · 2 November 2017

You did check brake fluid already right ?

comquat1 · 2 November 2017

jwmelvin said:
You did check brake fluid already right ?

I'll pull the console tomorrow night... and I didn't pop the hood tonight, just had a few min to pull the code quick.

jwmelvin · 2 November 2017

comquat1 said:
I'll pull the console tomorrow night... and I didn't pop the hood tonight, just had a few min to pull the code quick.

You might be able to get the access you need to the handbrake-switch connector just by removing the storage box. I forget where the wire is but remember it being right at the back of the console.

Old Guy · 2 November 2017

Definitely a code 2 on the ABS.

You can check for a ground on the parking brake circuit from the wiring connections at the float switch on the master cylinder. However, rather than do that, check the fluid in the master cylinder and disconnect the MC float switch - rules out a problem with a wonky float switch. If the brake system warning light is still on with the float switch disconnected that pretty much guarantees that the problem is with the parking brake lever mechanism / parking brake switch or adjustment of same. If that is the case you might as well start the dive into the center console. Its been too long since I pulled the console to clean my aspirator fan so I can't remember the details for removal - best to consult the service manual.

nsxspdfreak · 2 November 2017

Old Guy said:
So, brake system warning light lit up and ABS light on? As far as I can tell, there are only two things that cause the brake system warning light to come on. The parking brake is applied or the brake fluid is low. If the parking brake is applied (or the ABS 'thinks' that the parking brake is applied because of a ground fault) and you drive the car for more than 30 seconds this will cause the ABS system to generate an error code. If you retrieve the ABS error code and you get a code 2* that confirms that the issue is originating with the parking brake. Since the brake warning light was on and the ABS light came on about 1/2 mile later I suggest that the problem could be:

1 - the parking brake is on or partially applied or the parking brake switch is out of adjustment.
2 - the brake reservoir fluid switch appears to be connected in parallel with the parking brake switch so I think low fluid in the brake reservoir could trigger exactly the same symptoms.
3 - you have a chaffed wire in the brake warning circuit that is grounding and causing the warning lights to come on.

Pull the error code to confirm that it is code 2*. Then check the brake reservoir level first just because it is the easiest thing to check. After that look into the parking brake switch. With luck it will not be a wiring problem.

* Nsxspdfreak provided an ABS code list that identifies a different code (2-1) for the parking brake. I got my error code from the 1991 service manual which just lists a main code of 2 and no sub code. His codes may be from a later model year or there might be an error in the 1991 service manual or I just don't know how to read. Larry B might be able to confirm the correct error code for the 1991 system - parking brake error.

Sorry for the late response, but I see that you finally realized that the ABS light flashes it's own codes independent of the CEL. So I never have to jumper the OBD1 plug again I purchased the matching female connector and wired it to a micro toggle switch mounted inside the glove box. This way all I have to do is flip the switch to read the codes.

comquat1 · 2 November 2017

Old Guy said:
Definitely a code 2 on the ABS.

You can check for a ground on the parking brake circuit from the wiring connections at the float switch on the master cylinder. However, rather than do that, check the fluid in the master cylinder and disconnect the MC float switch - rules out a problem with a wonky float switch. If the brake system warning light is still on with the float switch disconnected that pretty much guarantees that the problem is with the parking brake lever mechanism / parking brake switch or adjustment of same. If that is the case you might as well start the dive into the center console. Its been too long since I pulled the console to clean my aspirator fan so I can't remember the details for removal - best to consult the service manual.

Ok, so I got into things tonight again, MC was at the bottom line so I added some brake fluid. That did not get the light to go out when I started the car. I’m assuming the two wires the go to the MC cap are the float switch? I can’t figure out how to disconnect that as I see each wire is covered by a rubber boot about six inches from the cap but those appear to be fixed connections under there (do they pull apart? I don’t want to break anything).

I also took the console apart and am wondering if I have a switch gone bad. Is there any way of testing that switch?

Sent from my iPhone using Tapatalk

BRAKE light and Anti lock light have lit up, where to look first?

Similar threads