2008-2015 Infiniti G37 ABS Light On: Common Causes and Fixes

By Core Brake Parts Tech Team — Circleville, OH warehouse

When the ABS light stays on in a 2008-2015 Infiniti G37, the anti-lock system has found a fault and switched itself off. Your normal brakes still work, but the wheels can lock in a panic stop and stability control is usually disabled too. On this car the most common culprits are a wheel speed sensor, its wiring or connector, or a damaged tone ring, and a scan tool reading of the stored code tells you which corner to look at.

How the ABS System on the G37 Works

Infiniti's factory specification sheet for the G37 lists a 4-wheel, 4-channel, 4-sensor Anti-lock Braking System, with Electronic Brake force Distribution (EBD) and Brake Assist as standard, and Vehicle Dynamic Control (VDC) standard on every version. In plain terms: each wheel has its own speed sensor and its own hydraulic channel in the ABS actuator, so the control unit can release and reapply pressure at one wheel without touching the other three.

The wheel speed sensors are the eyes of the whole system. VDC, traction control and EBD all read the same four signals. That is why a single bad sensor on a G37 very often lights up more than one lamp: ABS, and with it the VDC OFF and SLIP indicators. Seeing all three together does not mean three separate failures. It usually means one input the whole stability system depends on has gone bad.

Sport-package cars carry larger brakes: the same spec sheet lists 14.0-inch front and 13.8-inch rear rotors with 4-piston front and 2-piston rear calipers. The ABS hardware and the diagnosis are the same on standard and Sport brakes.

ABS Light vs Brake Light: Know Which One You Have

Low brake fluid is worth ruling out first because it is free to check. The fluid level drops slowly as pads wear, since the caliper pistons move outward and take fluid with them. If the reservoir is low and the pads are thick, you have a leak, and that needs attention before anything else.

Common Causes of an ABS Light on the G37

Wheel speed sensor or its wiring

This is the most frequent cause on any ABS car. As Brake and Front End explains, the system sets a fault when it loses a sensor signal (an open or shorted circuit) or when one sensor reads significantly differently from the others. Broken wires and corroded connectors are the most common problems, and the harness on each corner flexes with every suspension movement for years. On a G37 that has had recent brake, hub or suspension work, check first that the sensor harness was not stretched, pinched or left unclipped.

Debris on the sensor tip

Wheel speed sensors are magnetic. Metallic brake dust and rust flakes stick to the tip and weaken the signal. Pulling the sensor, cleaning the tip and the bore, and reinstalling it fixes more ABS lights than people expect.

Tone ring damage or rust

The sensor reads a toothed ring that turns with the wheel. Chipped, cracked or rust-swollen teeth distort the signal, and AA1Car notes that even small variations in tooth height can cause trouble. Rust is worst on cars driven through salted winters.

Worn wheel bearing

The sensor needs a steady air gap to the tone ring. According to AA1Car and Brake and Front End, typical gaps run from about 0.016 to 0.050 inch, and a loose or worn bearing lets the ring wobble, varying that gap and producing an erratic signal. If one corner also growls or hums at speed, suspect the bearing and hub, not the sensor.

Mismatched tire sizes

Brake and Front End points out that mismatched tire diameters change wheel speed readings and can upset ABS and traction control. A single replaced tire with a different size or much more tread than the other three can be enough on some cars. On the G37, remember that Sport and some other trims use different front and rear wheel widths, so replace tires in matched sets.

Steering angle sensor or ABS actuator

VDC also relies on a steering angle sensor. After an alignment, steering work or a battery disconnect, that sensor may need a calibration with a scan tool, and until then VDC OFF and SLIP can stay lit. Less commonly, the fault is inside the ABS actuator and control unit itself, which is a dealer or specialist repair.

How to Diagnose It

1. Check the basics. Brake fluid level, parking brake fully released, all four tires the same size and properly inflated.
2. Read the codes. A generic engine-code reader will not see ABS codes. You need a scan tool that reads the ABS/VDC module. The code will name the circuit or the corner.
3. Watch live data. With the scan tool showing all four wheel speeds, drive slowly in a straight line. A sensor that reads zero, drops out, or disagrees with the other three is your suspect. Brake and Front End notes that many newer systems flag a sensor that differs by as little as 3 to 5 mph.
4. Inspect the corner. Look at the harness, the connector, the sensor tip and the tone ring. Clean the tip and check for play in the wheel bearing.
5. Test before you buy. Sensor testing methods differ between passive and active sensors, so follow the procedure in the factory service manual rather than guessing from a resistance number meant for another car.

The Fix, and What to Do While You Are In There

A wheel speed sensor is usually one bolt and one connector, and on most G37 corners it is a driveway job once the wheel is off. A hub or bearing replacement is bigger: the caliper and rotor come off first, which makes it the natural time to look hard at your brakes. If the pads are near their wear limit or the rotors are grooved or warped, do them in the same visit so you only pay for that labor once.

For the G37 we carry fitment-matched pads, including the EBC Bluestuff NDX front brake pad set for the 2008-2015 G37, the matching EBC Bluestuff NDX rear pads for the G37, and the Hawk HPS front pad set for 2009-2012 G37 Sport models with the larger Sport brakes. You can also browse all brake pads, brake rotors and brake hardware kits.

After any repair, clear the codes and road test. The ABS light should go out once the system sees good signals from all four wheels. If it comes straight back, the code will point you to what is left.

Is There a Recall for the G37 ABS Light?

Infiniti's ABS actuator safety recall, which involves a pump seal that can leak and a risk of an electrical short, applies to the 2017 QX60, not the G37. That said, any open recall is tied to your VIN, so it only takes a minute to enter yours on Infiniti's official recall lookup and on NHTSA's site to be sure nothing is outstanding on your car.

Frequently Asked Questions

Is it safe to drive my G37 with the ABS light on?

With only the ABS light on, the base brakes still work, but the wheels can lock in a hard stop and VDC is usually off. Drive gently, leave extra following distance, and get it diagnosed soon. If the red brake light is also on or the pedal feels different, stop driving and have it inspected.

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

VDC and traction control use the same wheel speed signals as ABS. When one of those inputs fails, the stability systems shut down along with ABS, so one fault usually lights all three.

Can new brake pads or rotors cause the ABS light?

The parts themselves do not, but the work can. A sensor harness left unclipped, stretched or pinched during a brake job is a common cause. Check the wiring on the corner that was serviced first.

Will disconnecting the battery clear the ABS light?

It may turn the lamp off temporarily, but if the fault is still there it will return, and a battery disconnect can make the steering angle sensor need recalibrating. Fix the cause, then clear the code with a scan tool.

Do I need to replace all four wheel speed sensors?

No. The system monitors each wheel separately, and the code and live data show which one is at fault. Replace only the sensor that tests bad.

Sources

1. Infiniti 2009 G37 Sedan Technical Specifications - 4-wheel/4-channel/4-sensor ABS, EBD, Brake Assist and VDC standard; Sport brake rotor sizes and caliper pistons
2. Brake and Front End: Diagnosing Wheel Speed Sensors - what sets an ABS fault, wiring and contamination failures, 3-5 mph mismatch threshold, tire size effects
3. AA1Car: Diagnosing ABS Wheel Speed Sensors - air gap range, tone ring damage, wheel bearing effects on sensor signal
4. Infiniti USA: ABS Actuator Safety Recall - recall scope (2017 QX60), defect description and remedy