Help needed with ALB system

Hello, Hope im posting in the correct section.

New nsx owner here and i am having some trouble with the ALB/TCS system.

Firstly....when both check lights were on i discovered that the connector for the front left wheel sensor was destroyed. The sensor side pins where just out and hanging. Those red and white wires in the wheel sensor main cable....is there a positive and negative to it ....does it matter which side of the connector. The car side connector is fine.

For that i guessed and i connected it and reset the system by pulling the ALB2,3 fuse. The TCS light remains off now....but while driving the ALB light alone now comes on after a while.

Upon checking this i realized the main ALB 40A fuse was blown. I replaced and it blew again the next time i went out with the car.

If i reversed the terminals on the speed sensor by mistake will this cause this?? if it doesnt matter please advise me where else i can check.

Thank you for any help i get.

It's not the speed sensor, they're just a variable reluctance signal that feeds a variable frequency sine wave into the ABS ECU, I don't think there's a high/low pair. I'm assuming this is the original 91-97? type ABS with the separate pump and solenoid modules? The 40A fuse is only connected to the ABS pump, which might draw up to 35A for a very short time on a normal startup if it's working correctly. It sounds like the pump motor is either frozen or the pump is really gummed up causing the excess current. Do you ever hear a sort of 'chattering' sound when you first start the car before the fuse blows? the pump makes a distinctive and unpleasant sound when it first pressurizes the system, and then cycles again and again and again if it's leaking internally or one of the solenoids is stuck, it might even have overheated and failed if it was allowed to run continuously long enough.

elmnt80 said:

Hello, Hope im posting in the correct section.

New nsx owner here and i am having some trouble with the ALB/TCS system.

Firstly....when both check lights were on i discovered that the connector for the front left wheel sensor was destroyed. The sensor side pins where just out and hanging. Those red and white wires in the wheel sensor main cable....is there a positive and negative to it ....does it matter which side of the connector. The car side connector is fine.

For that i guessed and i connected it and reset the system by pulling the ALB2,3 fuse. The TCS light remains off now....but while driving the ALB light alone now comes on after a while.

Upon checking this i realized the main ALB 40A fuse was blown. I replaced and it blew again the next time i went out with the car.

If i reversed the terminals on the speed sensor by mistake will this cause this?? if it doesnt matter please advise me where else i can check.

Thank you for any help i get.

Click to expand...

First off, the wheel speed sensor problem is not the cause of the 40 A fuse failure. The 40A #30 fuse is only for the ABS unit motor. It has nothing to do with the ABS control unit which the wheel speed sensors are connected to.

The wheel speed sensors are reluctance type sensors and the polarity of the connection can be important. The shape of the waveform that the sensor produces as the toothed wheel passes the sensor will change if the polarity of the winding in the sensor is reversed. It may depend on the software that the ABS controller is using to monitor the wheel speed; but, I would normally expect that reversing the polarity of the sensor would screw the software up leading to error codes. If you have connected it up and the ABS and TCS are not triggering codes for wheel speed sensor problems, you probably lucked out and connected it correctly. If you want to be sure, go to the NSX Prime Wiki page and download the .pdf version of the service manual that applies to your car. Find the wiring diagram for the ABS system and it will show the connections with wire colors to the wheel speed sensors. It also shows the polarity markings on the wheel speed sensors. I would bet that the red wire on the wheel speed sensor is the +.

With respect to your bigger problem, I expect that you have an ABS modulator issue. You didn't specify your model year (rather important if you are going to ask for help); but, I expect that you have an early model year which was known for problems with the ABS modulator. I have a 2000 with the later version modulator so I have no direct experience with the early ABS. I suggest you do a search on the Prime Forum using a descriptor like 'ABS Modulator' or 'ABS Modulator Problems' or 'ABS Modulator Failure'. I think you will find lots of reading material. Also, once you get a copy of the service manual you can go through the diagnostic process for the modulator.

Hey guys..thanks for the replies.

For everyone viewing ...i am sorry for not specifying the model nsx. Slight oversight on my part. Its a 91 NSX 5 spd RHD imported from japan....early chassis number.

On startup i dont hear any strange noises and the ALB check light doesnt come on at all. When i replaced the fuse, it doesnt blow on startup either. Only after driving a short distance away the light comes on ...then i pull over and check the fuse i see it blown.

With regards to the wheel sensor..i have looked at the service manual and i saw the polarity of the car side sensor wire connectors. It does show the red and white on the other side of the connector going to the sensor. I really did go with the assumption the red was +ve and matched to the car side +ve as shown in the manual.

I will definitely look in to the Modulator issues. Where i live there are only about 2 NSX's and no one knows much about them....especially that early ALB system.... so i am really trying on my own with the help of the FSM.

I appreciate any help i get.

I would first check if your ABS pump is running when you connect 12V direct to it. Then you can check if it is running when you bypass the ABS pump relay (see points 1 to 4 here to bypass the relay : http://www.danoland.com/nsxgarage/brakes/abs/abs.htm )

Hello thanks for the reply,

I actually realized i should have done that..last night i did bypass the relay and discovered the pump was stuck. I hear it clicking but not running. As Jimminh said...beacause of this it seems like it pulling way too much amps and blowing the fuse.

Now looking around for a pump rebuild thread.

Thank guys for the input. Much appreciated.

asylum said:

I would first check if your ABS pump is running when you connect 12V direct to it. Then you can check if it is running when you bypass the ABS pump relay (see points 1 to 4 here to bypass the relay : http://www.danoland.com/nsxgarage/brakes/abs/abs.htm )

Click to expand...

I have parts left from a low-mileage system if you're interested. I bought a complete unit just to get the accumulator, so I have the pump and the solenoid body left. Parts came from Ben at Daisey and he said they were from a 24K mile '92. Ben's a solid guy so that would be accurate mileage. PM me if you want to get the pump and we'll work it out.