ABS Light

[rather_b_boatin]

Does anyone know what would cause the ABS light to come on the dash? How to read the code that trips it? The light came on, I topped off the fluid level (it was a little low). Checked all relays and fuses, then the the pad wear, all pads had over 50% meat on them. Disconnected the batter for 5 minutes and I've still got the light?!!

[BeZerK2112]

The best thing to do for that would be to hook it up and check the code.

When i was haveing ABS problems it was my own fault from not tieing my wheel senor wire up properly and it rubbed on the CV boot until the wires crossed and threw the light every time I started the car, throwing a bad sensor code. I would check your wheel sensors first, but hooking it up and getting the code could tell you that.

Auto zone has computers to help you diegnose codes. Good luck!

[Nahkapohjola]

Open each sensor connector (near each wheel), then ABS box connector. Clean, add contact grease. ABS connectrors are cheap tinned ones (3gen) and the tin 'escapes' from under the pins causing bad contact. Solution: move connector 1mm.
Should help...

see http://www.cardomain.com/ride/748507/14

ABS connector see: http://www.cardomain.com/ride/748507/18

[rather_b_boatin]

Checked all 4 sensors and connectors, fusible links, and fuses. Shot contact cleaner in all connectors. No avail, still have ABS light. Does anyone else have any other suggestions? Should I take the wheels off and check the trigger wheel? Would I have to remove the brake discs for that? Thanks in advance for any help.

[sparkeykev]

Originally Posted by rather_b_boatin

Does anyone know what would cause the ABS light to come on the dash? How to read the code that trips it? The light came on, I topped off the fluid level (it was a little low). Checked all relays and fuses, then the the pad wear, all pads had over 50% meat on them. Disconnected the batter for 5 minutes and I've still got the light?!!

this site will tell you how to acess codes and what codes are
http://www.auto-diagnostic-codes.com/

[Nahkapohjola]

The error code may give indication, possibly even correct guess. Most probable cause (in this order) are: connector oxidation, low supply voltage (at ABS computer), broken wire/sensor. Measure /compare each sensor wire resistance.

see http://www.cardomain.com/ride/748507/18

[rather_b_boatin]

Thanks for all the advice. Tried the website and, unfortunately, one of the pins (on the obd 2 connector, #15) it said to jumper had no harness wire attached. I'll try the resistance test when I have more time (vacation this week) and post how I make out.

[rather_b_boatin]

Okay, the fronts checked out at 1.26k ohms each and rears 39.8k ohms each. I'm not sure if that normal but it is consistant between the 2 sets. Gotta keep digging I think.

[Nahkapohjola]

I guess the front readings are ok ... all should give equal reading (when measured from connector attached to sensor wire, about one foot from wheel).

[rather_b_boatin]

So the rears both (even though equal) sound a little high? Maybe worth going to autozone and seeing if that resistance matches a new one.

[Nahkapohjola]

All should be equal.

When there are two wires into a sensor, theres a coil w/o any electronics (then resistance reading has a meaning). If there are three or more wires, the sensor itself can contain electronics (resistance reading may be irrelevant).

Try to get the codes...

Whats the maxima model? On 1993-94 models, drive the vehicle over 20 mph (32 km/h) for at least one minute. With the engine running, inspect the LED on the control unit. The codes will appear as flashes of the LED.

On 1995-98 models, drive the vehicle over 20 mph (32 km/h) for at least one minute. Turn the ignition OFF. Ground the 4 terminal of the data link connector under the dashboard, then turn the ignition ON. The codes will appear as flashes of the ABS lamp on the dashboard. To see code list & later models; follow the links on page http://www.cardomain.com/ride/748507/21

[rather_b_boatin]

Thanks for the advice. I found out that the fronts and rears (sensors) do have different part #'s-possibly diff. resistance? Hub diameter is smaller on rear than front. (diff. coil to p/u pulse from smaller trigger wheel) I can't find a speck on what that resistance should be, leads me to beleive big Nissan dealer secret you'll never know?? Having horrible luck trying to pull the code myself. It seems no over the counter diagnostic tool that me or you can purchase will reveal the code. Wife's Max is a 2001 and does not have the LED, box, or a "ground out" terminal (that I know of) to flash ABS light. I followed the instructions to a tee on an earlier post with a website link (car domain did not cover 2001) to jumper 2 terminals, but 1 terminal it said to jumper was not a live wire on DTC link. Hate to pay our local CROOK dealer to read ($100) it but seems I'm running out of options...

[Nahkapohjola]

Check your PM

This may be good? http://www.scangauge.com/

[Nahkapohjola]

Few issues copied from 2k2 Maxima FSM Brake-section:

Wheel Sensors, FSM BR-40:
- For M/T models:
The sensor unit consists of a gear-shaped sensor rotor and a sensor
element. The element contains a bar magnet around which a
coil is wound. The sensor is installed on the back side of the brake
rotor. Sine-wave current is generated by the sensor as the wheel
rotates. The frequency and voltage increase(s) as the rotating
speed increases.
- For A/T models:
The front sensor units consist of a gear-shaped sensor rotor and a
sensor element. The element contains a magnet and IC. The front
wheel sensors are installed on the front of the wheel knuckles. As
the wheel rotates, the sensor generates a square-wave signal. The
frequency increase as the wheel speed increase.



See self Diagnostics with Nissan Consult-II
from FSM BR-48 forward


Sensor resistance testing:

from BR-62 forward
CHECK WHEEL SENSOR CIRCUIT FOR M/T MODELS
1. Disconnect control unit connector.
2. Check resistance between control unit harness connector E9 terminals.
Front RH wheel
Terminals 10 (B/W) and 25 (OR)
Front LH wheel
Terminals 8 (G) and 23 (R/B)
Rear RH wheel
Terminals 14 (B) and 29 (W)
Rear LH wheel
Terminals 12 (R/W) and 27 (L/W)
Resistance: 0.8 - 1.85 kW

CHECK WHEEL SENSOR CIRCUIT FOR A/T MODELS
1. Disconnect control unit connector.
2. Check resistance between control unit connector terminals.
Front RH wheel
Terminals 9 (B/W) and 24 (L/OR)
Front LH wheel
Terminals 7 (G) and 22 (R/B)
Rear RH wheel
Terminals 28 (W) and 13 (B)
Rear LH wheel
Terminals 26 (L/W) and 11 (R/W)
Resistance: 0.8 - 1.85 kW

Check resistance of each sensor. (See NOTE.)
Resistance: 0.8 - 1.85 kW (For M/T model)
I Check signal from sensors by “Simple oscilloscope” function of CONSULT-II (For A/T model) (Scale: 0.2 V/Div, 20
ms/Div)

Check clearance between sensor and rotor.
Clearance:
Front
0.273 - 0.925 mm (0.0107 - 0.0364 in)
Rear
0.385 - 0.973 mm (0.0152 - 0.0383 in)

Voltage supply to wheel sensor -checkup (if ok, then ABS ctrl logic is functional up to a point...)
1. Disconnect wheel sensor connector.
2. Check voltage between body side terminal of wheel sensor connectors and body ground. Ok if voltage more than 8V.

[Nahkapohjola]

Originally Posted by Nahkapohjola

"...Resistance: 0.8 - 1.85 kW..."

FYI: that hillaryous txt is authentic copy from the Nissan manual... should be kΩ ... hopefully those values are correct?! 0.8 - 1.85 kΩ