1994 Pathfinder - ABS Light ON

[PathinTX]

Hi

91-95 Nissan Pathfinder ABS Control Module 47850 92G00 OEM

https://parts.nissanusa.com/a/Nissan__/89924895__10618284/ANTI-SKID-CONTROL/D21_US_476A.html

 

I do not currently have ABS working on my 1994 Pathfinder 4x4 5-Speed

 

Is possible the ABS Control Module has gone bad

 

Does anyone know where it is located and if there is another possibility

 

Thanks

Robert

N of Dallas

 

Recent New Engine after 300,000+ miles

 

[Slartibartfast]

If the ABS light on the dash is on, the computer thinks something is wrong. The BR section of the service manual (free download from Nicoclub) will walk you through it. I recommend filming the flashing light with your phone so you can play it back, because it's not the most intuitive thing to decode. They can code for several different faults, including the computer. Mine coded for the speed sensor. Looks like the light will also come in if the ABS kicks in when you're in 4WD, and that's normal--it's just confused because the drivetrain is locked together through the transfer case, and the ABS can't unlock the front brakes, so unlocking the rear brakes has no effect.

 

If you can't get a response from the diagnostics plug, I guess it could be the computer, though I would check the fuse, the bulb in the cluster, and the wiring (the service manual has a check for this too) before ordering a replacement. The ABS computer should be under your driver's seat. It's the one with the rounded corners, not the box with the hole in the top (that's the alarm).

 

Also check the brake fluid level in your master cylinder. IIRC the low fluid sensor lights up ABS and BRAKE on the dash, but it's been awhile since I dealt with that one.

 

If the ABS light is not on, what makes you think it's not working? There is not much to this system, and it only works on the rear wheels. There is no pump to pulse the brakes. The service manual talks about noise and pedal vibration, though hell if I know how it would do that without a pump. I suspect they may have copied that text from the manual for a different model that used a more advanced system. The only noise I ever heard from mine was a click when the ABS tested itself.

 

I'm on my second WD21 and have never noticed the ABS kicking in on either of them. I ended up deleting the system while chasing another braking issue and have not noticed any changes in handling.

[Frenchy]

You definitely need to diagnose it. It is a very simple system. You have the controller, the actuator and the speed sensor on the rear axle. Before ordering parts(since they are pricey) you are best to diagnose first

[PathinTX]

Slartibartfast

 

The fluid level is prefect

 

How do I know the ABS is not working

 

Well if I'm going 50 mph and hit the Brakes the Brakes lock and the tires skid - that has never happened - plus i dont feel the clicking in the pedal

 

The ABS light is constantly on -

 

Before this light STAYED on - it would flash right after starting and then the light went off.

 

The ABS yes is only the rear wheels - but it WORKS Great when needed ..

 

 

[Frenchy]

Something to remember about the ABS on these vehicles. With it only being rear wheel ABS you can still lock up your front tires. You won't get any clicking through the brake pedal when it does operate. Even mine doesn't do that. All it does when it is working correctly is lower brake pressure to the rear brakes by whatever amount is needed according to the logic in the controller so the rear tires do not lock up and you have less chance of going into a skid. Thanks to do to help ensure things work correctly is making sure your brake pads rotors and calipers are in great shape along with making sure you bled the entire system including the actuator. Also if you have rear drums instead of rear disc brakes because you don't have an SE sport then good luck on getting that rear wheel ABS to work. Drum breaks are a pain in the ass to work with and make it hard for the rear ABS to do its job.

[PathinTX]

Frenchy

 

You have the controller, the actuator and the speed sensor on the rear axle.

those 3 units are on the rear axle

 

I have a 4x4

 

What do they look like

I dont see anything on the rear axle - or im blind to what im looking for

 

[PathinTX]

• Location: Plano, Texas
• Country: United States
• Model: SE
• Year: 1994

The Fluid level is prefect and there is no air in the system

 

 

Frenchy -  I lived in Telluride for a while  - years ago

Edited February 7 by PathinTX

[PathinTX]

Nissan 25010-74P00 Sensor Assembly-Speed Meter

 

https://www.nissanpartsdeal.com/parts/nissan-sensor-assy-spe~25010-74p00.html

[Frenchy]

Wrong speed sensor. That one is for the speedometer only. Look at your rear axle and you will see it wrapped around the pinion on the axle. It's a pricy thing.

[Frenchy]

Also don't get SE confused with SE Sport. The SE Sport comes with factory LSD Rear Disc Brakes adjustable shocks sun roof fog lights rear tire swing and roof rack. The shocks and brakes are the big notations to the package.

[PathinTX]

Also don't get SE confused with SE Sport.

The SE Sport comes with factory LSD Rear Disc Brakes adjustable shocks sun roof fog lights rear tire swing and roof rack.

The shocks and brakes are the big notations to the package.

 

I have ALL that

 

 

[PathinTX]

Look at your rear axle and you will see it wrapped around the pinion on the axle. It's a pricy thing.

 

https://www.rockauto.com/en/catalog/nissan,1994,pathfinder,3.0l+v6,1211960,brake+&+wheel+hub,abs+wheel+speed+sensor,1912

 

 

 

Now I am wondering if the ABS Wheel Speed Senor is BAD - that is effecting BOTH the ABS ( light on ) and now not working along with the Odometer Not Turning

Edited February 7 by PathinTX

[PathinTX]

Ok

 

I looked

I See the ABS Wheel Speed Senor around the pinion

How the Heck does that thing come off to replace ?

 

Nissan tells me it is :91-95 Nissan Pathfinder ABS Control Module 47850 92G00 OEM

https://parts.nissanusa.com/a/Nissan__/89924895__10618284/ANTI-SKID-CONTROL/D21_US_476A.html

 

 

What does the ABS Wheel Speed Senor - DO ?

What does the ABS Control Module - DO ?

 

[Frenchy]

Before you try to take it off and replace it why don't you do some diagnosis? If you go to Nico club you can get the service manual if you don't have it already. Take your time to go through the diagnosis steps for whatever code you have and you will be able to figure out the exact problem. If you are not confident in your diagnostic abilities I would highly recommend taking it to someone you trust that has very good diagnostic capabilities.

[Slartibartfast]

The ABS light on is good news. That means the computer knows there's a fault, and can tell you what it is. Pull the code and it'll tell you where to look. Otherwise you're just throwing expensive parts at what could be a wiring or even hydraulic fault for all we know. BR section is here.

 

The sensor on the rear axle tells the control module (computer) how fast the rear wheels are spinning. (Well, technically how fast the pinion is spinning.) The control module under the seat watches the sensor, decides when there's a problem, and controls the solenoids in the valve block accordingly. The valve block is bolted to the inside of the passenger's side frame rail, about even with the B pillar IIRC, and has a solenoid to block off the rear brakes from the master cylinder, a solenoid to dump brake pressure from the blocked-off rear circuit, and an accumulator to dump the pressure into. Its design and behavior are spelled out in the BR section of the service manual.

 

IIRC replacing the sensor requires removing the flange for the driveshaft. The PD section should cover it if BR doesn't. And, yeah, that's an expensive damn sensor.

 

Are you sure it's the rears that are locking? When my rear brake circuit wasn't working (long story, stubborn air pocket somewhere), the fronts would lock pretty easily, because they were trying to do all the work. A malfunctioning ABS valve block could block off the rear brakes and cause the same issue. I realized my rears weren't doing anything when I jacked up the back of the truck, put it in drive, and was unable to stop the rear wheels with the pedal.

 

If you're locking your rear brakes on pavement, I need to know what kind of pads you're running, because mine do not grab hard enough to do that.

[PathinTX]

CODES

I do not see a Code for ABS -- Unless this is the ABS Code ( 14 Vehicle Speed Sensor. )

 

For V6:
1. Turn the ignition switch on, but do not start the engine. All of the lights in the dash should be on.

2. For VG30E with slotted switch: Turn the 'diagnostic mode selector' screw on the ECU fully clockwise. The check engine light will go out. Wait 5 seconds, then turn the screw fully counter clockwise.

3. After it blinks both LED's 3 times move the toggle switch back to the on position. After about five seconds it will start to output out the diagnostic codes as with the 4-cylinder ECU. Note each code as it is displayed, the red LED flashing once for 10's, and the green LED flashing once for 1's. Meaning: One red flash and two green flashes means code 12.
 

4. To clear the ECU of any trouble codes, move the switch to the "DIAGNOSTICS" position then back to the "ON" position and turn off the key.

1986.5-1995 Nissan ECU Flash Codes(all engines)
 

11 Crank Angle Sensor/Camshaft Position Sensor.
12 Air Flow Meter/Mass Air Flow Sensor.
13 Engine Coolant Temperature Sensor.

14 Vehicle Speed Sensor.

21 Ignition Signal.

22 Fuel Pump.

23 Idle Switch.
24 Throttle Valve Switch.
25 Idle Speed Control Valve.
28 Cooling Fan Circuit.
31 ECM.
32 EGR Function.
33 Heated Oxygen Sensor.
34 Knock Sensor.
35 Exhaust Gas Temperature Sensor.
36 EGR Control-Back Pressure Transducer.
37 Knock Sensor.
38 Right hand bank Closed Loop (B2).
41 Intake Air Temperature Sensor.
42 Fuel Temperature Sensor.
43 Throttle Position Sensor.
44 ECCS Normal Operation.
45 Injector Leak.
47 Crankshaft Position Sensor.
51 Injector Circuit.
53 Oxygen Sensor.
54 A/T Control.
55 No Malfunction.
63 No. 6 Cylinder Misfire.
64 No. 5 Cylinder Misfire.
65 No. 4 Cylinder Misfire.
66 No. 3 Cylinder Misfire.
67 No. 2 Cylinder Misfire.
68 No. 1 Cylinder Misfire.
71 Random Misfire.
72 TWC Function right hand bank.
73 TWC Function right hand bank.
76 Fuel Injection System Function right hand bank.
77 Rear Heated Oxygen Sensor Circuit.
82 Crankshaft Position Sensor.
84 A/T Diagnosis Communication Line.
85 VTC Solenoid Valve Circuit.
86 Fuel Injection System Function right hand bank.
87 Canister Control Solenoid Valve Circuit.
91 Front Heated Oxygen Sensor Heater Circuit right hand bank.
94 TCC Solenoid Valve.
95 Crankshaft Position Sensor.
98 Engine Coolant Temperature Sensor.
101 Front Heated Oxygen Sensor Heater Circuit right hand bank.
103 Park/Neutral Position Switch Circuit.
105 EGR and EGR Canister Control Solenoid Valve Circuit.
108 Canister Purge Control Valve Circuit

Edited February 8 by PathinTX

[Slartibartfast]

Those are the engine computer codes. You want the ABS codes. Separate computer, different procedure. Spelled out on BR-34 and 35 of the '94 service manual that I linked in my last post.