2008-2013 Infiniti EX35 ABS Light On: Common Causes and Fixes

By Core Brake Parts Tech Team — Circleville, OH warehouse

An ABS light that stays on in a 2008-2013 Infiniti EX35 means the ABS computer found a fault during its self-test or while driving and switched anti-lock braking off. Normal braking still works, but without anti-lock help. On this crossover the most common causes are a wheel speed sensor or its wiring, a dirty or damaged sensor ring, a worn wheel bearing, or low brake fluid, and a scan tool that reads ABS codes will tell you which wheel or circuit to look at first.

How the ABS and VDC system works on the EX35

According to the EX35 owner's manual, the ABS detects the rotation speed at each wheel and varies brake fluid pressure so no wheel locks and slides. The system is made up of electronic sensors, electric pumps, hydraulic solenoids and a computer. Every time you start the engine and move off at low speed, forward or reverse, the computer runs a self-test. You may hear a clunk or feel a pulse in the pedal during that test, and the manual says that is normal.

If the computer senses a malfunction, it turns the ABS off and lights the ABS warning light. The manual also notes that ABS only operates once the car is moving above a slow walking-to-jogging pace, so some faults do not show until the car is rolling.

The same wheel speed signals feed the Vehicle Dynamic Control (VDC) system, which uses individual-wheel braking and engine output to control wheel slip, understeer and oversteer. That is why an EX35 with a wheel speed problem often shows several lights together: ABS, the VDC warning light, and sometimes the brake warning light. A flashing VDC light on a slippery road is the system working. A VDC light that stays on means VDC has gone into fail-safe and switched itself off.

Reading the warning lights: which combination means what

The manual is blunt about the red brake light: if the fluid is below the MIN mark, do not drive until the brake system has been checked, and low fluid can increase stopping distance and pedal travel.

Most common causes of an EX35 ABS light

1. Wheel speed sensor or wiring

Each wheel has a speed sensor reading a toothed tone ring or a magnetic encoder that turns with the hub. MOTOR magazine explains that passive sensors generate their own AC signal whose frequency and strength rise with wheel speed, while active sensors are powered by the control unit and send a digital signal. Delphi lists the usual failures: dirt and brake dust on the sensor tip, wiring damaged by vibration, internal short circuits, and damage done during other brake work. On a car in this age range, a harness chafed against a suspension part or a corroded connector at the wheel is as likely as the sensor itself.

2. Dirty or damaged tone ring or encoder

The ring the sensor reads can pick up rust scale, metallic filings and grime. MOTOR notes that warped or chipped tone rings and rust that changes the sensor gap all corrupt the signal, and passive sensors in particular can cause false ABS activation at low speed. If you feel the ABS pulse the pedal at a crawl on dry pavement, suspect a signal problem at one wheel.

3. Worn wheel bearing

Both MOTOR and Delphi point to wheel bearing play as a cause. When a bearing wears, the ring moves relative to the sensor, the gap changes and the signal drops out. A hum or growl that changes with road speed plus an ABS code for that corner is a strong hint. On many modern designs the magnetic encoder is built into the bearing seal, so the fix is a hub or bearing, not a sensor.

4. Low brake fluid or a hydraulic problem

The EX35 uses DOT 3 brake fluid per its owner's manual (Genuine NISSAN Super Heavy Duty Brake Fluid or equivalent DOT 3). Fluid drops slowly as pads wear because the caliper pistons sit further out. A sudden drop means a leak at a line, hose, caliper or the master cylinder. If you top up and the fluid disappears again, the manual says to have the system checked. See our brake lines and brake hoses if you find a weeping line.

5. Mismatched tires on AWD models

For AWD EX35s the manual says to always use tires of the same type, size, brand, construction and tread pattern on all four wheels, and warns that a circumference difference between axles can damage the drivetrain. Mismatched tires also make one axle turn at a different speed than the other, which wheel-speed-based systems can read as slip. It will not always set a code, but rule it out before buying sensors.

6. ABS actuator or control unit

The pump and valve block can fail, but it is the least common cause and the most expensive guess. Condemn it only after the codes and wiring checks point there. NHTSA's recall records list no ABS or brake system recall for the EX35, so a failed actuator on this model is a repair, not a free recall fix.

How to diagnose it step by step

1. Check the fluid first. Look at the reservoir with the car level. If it is below MIN, find out why before anything else.
2. Read ABS codes. A basic engine code reader often cannot see the ABS module. Use a scan tool that reads chassis or ABS codes. The code usually names a specific wheel sensor or circuit.
3. Watch live wheel speeds. Delphi recommends recording fault codes and checking signals with diagnostic tools. On a test drive, all four wheel speeds should track together; one that drops out or reads erratically is your suspect corner.
4. Inspect that corner. Look at the connector and the harness along the strut and knuckle for chafing, corrosion or a broken clip. Remove the sensor and clean the tip and its bore.
5. Check the bearing. With the wheel off the ground, rock it top to bottom and spin it to listen for roughness.
6. Clear codes and re-test. The ABS light may stay on until the self-test passes on the next drive.

Brake work that causes or cures an ABS light

Delphi lists damage during other brake service as a common cause of sensor failure. On the EX35 the sensor wiring runs close to the caliper and hose. When you replace pads or rotors, unclip and route the harness out of the way, never let the caliper hang on the hose or the sensor lead, and make sure nothing contacts the sensor when the new rotor goes on.

The ABS light will not come on just because pads are worn. The EX35 manual describes an audible pad wear warning instead: a high-pitched scraping sound, first only when braking, then all the time as wear continues. If you hear that, plan pads and inspect the rotors at the same time.

For the 2008-2013 EX35 we carry front pads such as EBC Redstuff ceramic front pads (DP31671C) and EBC Greenstuff front pads (DP21671), rear pads like EBC Redstuff ceramic rear pads (DP31955C), and slotted rotors including the EBC GD Sport front rotor set (GD7218) and EBC USR rear rotors (USR7351). Browse all brake pads and brake rotors.

How hard is the fix?

Cleaning a sensor or repairing a connector is an easy driveway job with basic tools. Replacing a wheel speed sensor is usually moderate; the hard part is a sensor seized in its bore, which needs penetrating oil and patience. A hub or bearing replacement is a bigger job, and on AWD models the front involves the axle nut and drive shaft. Anything in the ABS actuator, or bleeding the system after hydraulic work that let air reach the actuator, is best left to a shop with a scan tool that can run the ABS bleed routine. Tighten all fasteners to the values in the factory service manual.

Frequently Asked Questions

Is it safe to drive my EX35 with the ABS light on?

The owner's manual says the brakes work normally without anti-lock assistance, so you can drive carefully to get it diagnosed. Expect the wheels to lock in a panic stop on wet or icy roads. If the red brake light is also on or the fluid is below MIN, do not drive it.

Why are the ABS, VDC and SLIP lights all on at once?

VDC and traction control rely on the same wheel speed data as the ABS. When the ABS computer sees a sensor fault it shuts the related systems down, so one bad sensor usually lights several warnings.

Will new brake pads turn off the ABS light?

Not by themselves. Worn pads trigger a scraping wear warning, not the ABS light. Low fluid from worn pads can light the red brake warning, so check the level, and make sure the sensor wiring was not disturbed during the job.

What brake fluid does the EX35 use?

DOT 3, per the owner's manual: Genuine NISSAN Super Heavy Duty Brake Fluid or an equivalent DOT 3 fluid from a sealed container.

Can a bad wheel bearing cause an ABS light?

Yes. Bearing play lets the tone ring or encoder move away from the sensor and the signal drops out. If the ABS code points to one corner and that wheel hums or has play, replace the bearing or hub.

Sources

1. 2011 Infiniti EX35 Owner's Manual - ABS and VDC warning light meanings, ABS self-test, DOT 3 brake fluid, pad wear warning, AWD tire matching
2. NHTSA recall records for the Infiniti EX35 - no ABS or brake system recall listed for the EX35
3. Delphi Technologies: Making sense of your sensors - ABS sensor - wheel speed sensor function, failure causes and diagnosis
4. MOTOR: Brake Shop - Wheel Speed Sensors - passive vs active sensors, air gap, tone ring and bearing faults