You’re driving along, everything feels fine, and suddenly the odometer flashes “Er 55.”
Your cruise control stops working, maybe the ABS light flickers on, and now you’re wondering — is my Subaru about to quit on me?
ER 55 on a Subaru (often shown as ER SS) indicates a fault in the ABS wheel-speed sensor or broken sensor wire, meaning the ABS system can’t read wheel speed and needs inspection or sensor replacement.
This guide breaks down what ER 55 really means, why it happens, how to fix it, and what to do if you see it again.
What ER 55 Actually Means
Many Subaru owners think “ER 55” is a random electronic glitch. In reality, it’s shorthand for an error in the wheel-speed sensor circuit, part of the vehicle’s ABS (Anti-Lock Braking System) and traction-control network.
In some models, the display doesn’t clearly show letters, so “ER SS” — short for “Error Sensor System” — can look like “ER 55.” That’s why you’ll find both codes discussed interchangeably in Subaru forums and service manuals.
Here’s the simple version: When one of your wheel-speed sensors stops sending a proper signal, the ABS computer throws up that “ER 55” alert. It’s your car’s way of saying, “Hey, I can’t read speed from one of the wheels — something’s wrong down here.”
Because the ABS and cruise control depend on those sensors, the system shuts them down temporarily. You’ll still have normal braking power, but anti-lock braking and traction control won’t work until the fault is fixed.
Why It Happens — Common Causes Behind the ER 55 Code
The wheel-speed sensors on a Subaru sit close to the wheel hubs. They constantly measure how fast each wheel spins, helping the ABS prevent skidding and keeping traction steady on slippery roads.
Unfortunately, those sensors live in one of the harshest spots on your vehicle — right next to water, dirt, salt, and road debris. Over time, that environment takes a toll.
Here are the most common causes for the ER 55 message:
- Dirty or damaged wheel-speed sensor
- Road grime, mud, or brake dust can block the sensor’s magnetic signal.
- Small impacts, like hitting a pothole or curb, can crack or loosen the sensor.
- Corroded or broken wiring
- Moisture or road salt corrodes the connectors that link the sensor to the ABS module.
- Sometimes the wire simply wears through after years of vibration.
- Wheel-bearing or hub replacement gone slightly off
- If a wheel bearing or brake job disturbed the sensor alignment, it may lose signal.
- Failed ABS module (less common)
- The main ABS control unit rarely fails, but when it does, it can trigger the same error.
- Recent off-road or winter driving
- Deep snow, ice buildup, or muddy trails can temporarily block sensor readings.
Any one of these can cause the system to lose contact with a sensor and light up the error.
How to Diagnose It the Right Way
If you’re mechanically inclined, you can start the troubleshooting process at home. If not, any shop with a proper scan tool can pinpoint the problem in minutes.
Here’s how diagnosis usually goes:
- Visual inspection
- Jack up the car safely and look behind each wheel where the sensor mounts.
- Check for dirt, rust, or broken wires. Sometimes cleaning off mud solves it.
- Check the connectors
- Unplug the sensor harness near the wheel and inspect for corrosion or greenish residue.
- Apply a little dielectric grease when reconnecting.
- Use a proper scanner
- A basic OBD-II reader won’t show ABS faults. You’ll need one that reads ABS codes.
- The scan will tell you which wheel sensor is failing — front left, rear right, etc.
- Verify continuity
- If you have a multimeter, test the sensor’s resistance and wiring continuity.
- A dead or inconsistent reading means the sensor or wiring is bad.
- Clear the code and test drive
- After fixing or cleaning, clear the code with the scanner and drive a short distance.
- If it doesn’t come back, you’re good to go.
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Fixing the ER 55 Problem
1. Cleaning or reconnecting
Sometimes, all it takes is cleaning the sensor tip or reconnecting a loose plug. A buildup of mud or corrosion can interfere with the magnetic signal.
2. Replacing a faulty sensor
If the scan tool identifies one wheel sensor as “no signal,” replacement is usually straightforward:
- Remove the bolt holding it in place (a small hex or 10 mm).
- Gently twist and pull it out — if it’s stuck, don’t force it; soak it with penetrating oil first.
- Install the new sensor and plug in the connector.
Typical cost:
- Sensor part: $60–$120
- Labor: $50–$80 per wheel
3. Wiring repair
If you find damaged wiring, a splice repair or new harness section fixes it. This costs less than a new sensor but requires soldering or crimping the connection properly.
4. ABS module issues
A failing module is rare but expensive — usually $400–$700. Get a second opinion before replacing it; sometimes corrosion at the connector mimics a module failure.
After the issue is fixed, the ER 55 message clears automatically, or you can erase it with a scanner. Drive a short distance and verify that the ABS light stays off.
Is It Safe to Keep Driving?
If the ER 55 code pops up while you’re on the road, you don’t have to pull over immediately — your brakes still work. However, understand what’s missing: the safety net of ABS and traction control.
Without those systems, your wheels can lock under heavy braking or spin on slippery pavement. Drive cautiously, keep extra distance between you and the next car, and avoid sudden stops.
Think of it like driving an older car before ABS existed — functional, but less forgiving.
Preventing ER 55 from Coming Back
Once you’ve fixed it, a little prevention goes a long way.
- Keep the sensor area clean. When washing your car, spray gently around the wheel wells to remove mud and salt.
- Avoid high-pressure spray directly on connectors. It can force water into the plugs.
- Inspect during tire rotations. Ask your shop to check sensor wiring while the wheels are off.
- Seal connections. A dab of dielectric grease keeps out moisture.
- Watch after winter. If you live in a snowy area, rinse the underside regularly to prevent corrosion.
Simple upkeep can keep the system healthy for years.
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Clearing Up Common Misconceptions
A few websites claim ER 55 means a problem with the fuel system or evaporative emissions. That’s incorrect. Subaru’s fuel or vapor-system issues trigger “P” codes (like P0455), not “ER” codes.
Here’s the truth:
| Myth | Reality |
| ER 55 is a fuel-tank pressure issue | It’s an ABS/wheel-speed sensor fault |
| It affects engine performance | It affects traction and braking systems only |
| It requires immediate towing | You can drive cautiously until it’s repaired |
Knowing the difference saves time, stress, and unnecessary parts replacements.
Related Subaru Error Codes
If you’re researching Subaru warning codes, you might also encounter:
- ER 65: Often linked to communication errors within the ABS system.
- P0420: Catalytic converter efficiency below threshold — an engine code.
- ER SS: The same as ER 55, depending on how the display renders it.
Each code points to a specific system, so always use a proper scanner to confirm before replacing parts.
How Mechanics Handle It
When a Subaru rolls into a shop with an ER 55 code, most technicians know exactly where to start. They’ll plug in a Subaru-compatible scanner, check live data from each wheel sensor, and confirm which one isn’t reading.
If it’s just dirty, they’ll clean it. If it’s broken, they’ll replace it — usually within an hour. Good shops test drive the car afterward to ensure the ABS light stays off and that the system activates properly under braking.
For peace of mind, you can ask to see the old sensor. Most have tiny cracks or rust at the tip where water seeped in.
What You’ll Feel When It’s Fixed
The best sign your fix worked is what you don’t feel. No warning lights, no codes, and the cruise control works again.
When you brake hard on loose gravel or wet pavement, you’ll hear and feel the familiar pulsing of the ABS engaging — that’s how you know the system’s alive and well again. Many Subaru owners describe a noticeable improvement in braking confidence once the issue is resolved.
Quick Recap
- ER 55 appears on the odometer when the ABS system detects a wheel-speed sensor fault.
- It disables ABS and traction control until the problem is repaired.
- The most common causes are dirt, corrosion, or a failed sensor.
- Cleaning or replacing the sensor usually clears the code.
- Normal braking still works, but drive carefully until the system’s restored.
What does ER 55 mean on a Subaru Outback
ER 55 on a Subaru Outback means there’s a problem with the ABS wheel-speed sensor or its wiring. It stops the ABS and traction system from working until the sensor is cleaned, fixed, or replaced.
What does ER 55 mean on a Subaru Impreza
If your Subaru Impreza shows ER 55, it means the ABS system can’t read one wheel’s speed. Usually, a damaged or dirty sensor or wire is to blame. Cleaning or replacing it fixes the issue.
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What does ER 55 mean on a Subaru Out
ER 55 on a Subaru Out model appears when the wheel-speed sensor fails to send signals to the ABS system. It’s a common issue caused by dirt, rust, or a broken sensor wire.
What does ER 55 mean on a Subaru Forest
On a Subaru Forester, ER 55 shows an ABS or wheel-speed sensor fault. It’s often due to a dirty or faulty sensor. Your brakes still work, but ABS and traction control stop until repaired.
Subaru Error 55 Reset
To reset Subaru Error 55, repair or replace the bad wheel-speed sensor first. Then, clear the code using a scan tool or disconnect the battery for a few minutes. The warning disappears after fixing.
ER 55 Subaru Outback 2005
In a 2005 Subaru Outback, ER 55 means a wheel-speed sensor is faulty or disconnected. The ABS light often comes on too. Check for damaged wires or replace the sensor to clear the message.
Error 55 Subaru Outback 2006
Error 55 on a 2006 Subaru Outback usually means the ABS sensor isn’t working right. It may be dirty or broken. Cleaning or replacing the sensor and resetting the system usually solves it.
ER 55 Subaru Legacy 2008
If your 2008 Subaru Legacy shows ER 55, the car’s ABS can’t detect a wheel’s speed properly. This happens when a wheel-speed sensor or wire is damaged. Repairing it restores the ABS function.
ABS Light and Error Code 55 and Cruise Control
When the ABS light and Error Code 55 appear together, your Subaru’s ABS system has lost a wheel-speed signal. Cruise control also turns off for safety until the faulty sensor or wiring is repaired.
Subaru Outback ABS Light and ER55 Code
Seeing an ABS light and ER55 on your Subaru Outback means a wheel-speed sensor isn’t working right. It stops the ABS and traction system temporarily. Replacing the damaged sensor usually clears the warning.
Code P0456 Also ER 55 on Dash
If Code P0456 and ER55 appear together, they represent separate issues. P0456 points to a small EVAP leak, while ER55 means a wheel-speed sensor fault. Fixing both restores the car’s performance and safety.
ABS and Error Code 55 or SS
When you see ABS and Error Code 55 or SS, it means your Subaru’s system can’t read wheel speed correctly. The ABS and traction features stop working until the broken or dirty sensor is fixed.
Help with ’05 Outback Error Code ‘ER55’
In a 2005 Subaru Outback, ER55 means the ABS sensor or wire is damaged. The system disables ABS and cruise control as a precaution. Checking and replacing the bad sensor will solve the issue.
Error 55, ABS, Check Engine and Cruise Control
If all these lights appear together, multiple systems are affected. The ABS and cruise issues come from a faulty wheel-speed sensor. The check engine light may show a separate problem needing diagnostic attention.
Er IU (or 1U) and Er 55 on Odometer Screen on 2009 Subaru Outback
On a 2009 Subaru Outback, Er IU or Er 55 both indicate electronic faults. Er 55 points to a bad wheel-speed sensor, while Er IU may signal a display or communication issue within the system.
FAQs
What does ER 55 mean?
ER 55 means your Subaru’s ABS wheel-speed sensor isn’t working properly, causing the ABS and traction systems to stop temporarily.
How to fix EyeSight error Subaru?
Clean the windshield around the cameras, restart the car, and if the EyeSight error stays, have sensors checked or recalibrated.
What is error 55 on a 2006 Subaru?
Error 55 on a 2006 Subaru means a bad or dirty wheel-speed sensor causing ABS and cruise control to turn off.
Why is my Subaru having trouble accelerating?
Your Subaru may struggle to accelerate due to clogged filters, bad spark plugs, dirty sensors, or transmission and fuel issues.
What does response code 55 mean?
Response code 55 means the system detected a fault, often related to sensor failure or communication errors inside the vehicle’s control unit.
How to reset a Subaru transmission control module?
Turn off the car, disconnect the battery for 30 minutes, reconnect it, then drive gently so the system relearns driving patterns.
What is system error 55?
System error 55 usually means a problem with the wheel-speed sensor or its wiring, affecting the ABS and traction systems.
ER 55 code and ABS light on related to airbag recall?
No, the ER 55 code and ABS light aren’t linked to the airbag recall; they’re about the ABS wheel-speed sensor issue.
What does Error 55 mean on 2007 Subaru Outback?
On a 2007 Subaru Outback, Error 55 means the ABS wheel-speed sensor has failed or disconnected, disabling traction and cruise control.
How to fix error code 55 on Subaru Legacy EJ20 engine?
Check and clean the wheel-speed sensors, inspect the wiring, replace any damaged parts, then clear the error using a scan tool.
Conclusion
The ER 55 message on a Subaru isn’t as scary as it looks — it’s simply your car’s way of saying there’s a problem with the ABS wheel-speed sensor or its wiring. While the brakes still work normally, ABS and traction control shut off until the issue is fixed. Most of the time, cleaning or replacing the faulty sensor clears the code quickly.
By keeping your wheel sensors clean, checking wiring during routine maintenance, and addressing warnings early, you can avoid repeated ER 55 alerts. With a quick inspection or repair, your Subaru will be back to smooth, safe driving in no time.