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C0663Chassis · ABS & brakesGeneric (SAE) code

C0663: Left Rear Wheel Speed Sensor B Intermittent/Erratic

Left Rear Wheel Speed Sensor B Intermittent/Erratic: the signal is intermittent or erratic. Wheel-speed signals feed ABS, ESC, traction control and the speedometer.

Severity
Urgent
Can I drive? Not recommended beyond getting it to a shop.
Typical labor cost
$65–$250 est.
30 min–2 h at an assumed $125/hr · parts extra · use your rate
Most common fix
Connector loose or oxidized
DIY difficulty: Moderate · DIY-friendly
01 —What it means

What C0663 means

C0663 is a generic OBD-II chassis code in the ABS & brakes group.

C
Chassis
0
Generic (SAE)
6
Subsystem group
63
Specific fault
How to read C0663. We group it under ABS & brakes.
Check engine light
Usually on
Emissions-related
No
Limp mode possible
Yes
Drive cycle to clear
Required
Code data: OBDex (CC0)

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02 —Symptoms

Symptoms

What drivers typically notice
  • ABS warning light on
  • ESC/stability control deactivated
  • Possible reduced brake assist
  • Speedometer may behave erratically
Code data: OBDex (CC0)
03 —Causes

Common causes

Ranked from most to least likely
  1. 01Connector loose or oxidizedMost likely
  2. 02Connector with intermittent contact under vibrationLess likely
  3. 03Harness routed against vibrating componentLess likely
Code data: OBDex (CC0)
04 —Severity

Can I drive with C0663?

Urgent

Not recommended beyond getting it to a shop.

This fault can put the vehicle in limp mode with reduced power, which can make merging and passing unsafe. Have it diagnosed as soon as possible.

Why we rate it urgent

  • Can put the vehicle in limp mode (reduced power)
  • Turns on the check engine light
  • Needs a drive cycle to confirm a repair

Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.

Code data: OBDex (CC0)
05 —Diagnosis

How to diagnose C0663

General procedure — follow the service manual for your vehicle
  1. 1

    Confirm the code and save freeze-frame data

    Read the codes with an OBD-II scan tool and note every code, not just C0663. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.

  2. 2

    Fix other faults first

    If other codes are stored, start with power-supply, sensor-circuit and communication codes. They can cause this code as a side effect.

  3. 3

    Check live data

    Watch the related sensor and actuator readings in live data (LR Wheel speed sensor B) and compare them with expected values in the service information for your vehicle.

  4. 4

    Test the likely causes in order

    Start with the most likely cause and work down: Connector loose or oxidized; connector with intermittent contact under vibration; harness routed against vibrating component. Test before replacing parts.

  5. 5

    Check for recalls and service bulletins

    Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.

  6. 6

    Clear the code and verify the repair

    After the repair, clear the code and complete a full drive cycle (cold start, idle, steady highway cruise, deceleration). The code is fixed when the related readiness monitor completes without it returning.

Code data: OBDex (CC0)
06 —Cost

C0663 repair cost estimate

Labor only — set your local shop rate
Labor estimate for C0663
$65–$250
30 min–2 h of labor × $125/hr (assumed rate) · parts extra

Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.

DIY difficulty
Moderate
Good DIY job?
Yes, with a scan tool

Needs a scan tool and some experience with testing.

Code data: OBDex (CC0)
07 —Components

Parts and systems involved

  • LR Wheel speed sensor B
Code data: OBDex (CC0)
09 —FAQ

C0663 FAQ

What does C0663 mean?

C0663 means “Left Rear Wheel Speed Sensor B Intermittent/Erratic”. Left Rear Wheel Speed Sensor B Intermittent/Erratic: the signal is intermittent or erratic. Wheel-speed signals feed ABS, ESC, traction control and the speedometer.

Is C0663 serious? Can I keep driving?

We rate C0663 as urgent severity. Not recommended beyond getting it to a shop. This fault can put the vehicle in limp mode with reduced power, which can make merging and passing unsafe. Have it diagnosed as soon as possible.

What causes C0663?

The most common causes, from most to least likely: Connector loose or oxidized; Connector with intermittent contact under vibration; Harness routed against vibrating component. Test before replacing parts, because several causes can set the same code.

How much does it cost to fix C0663?

Typical labor is about $65–$250 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.

Can I fix C0663 myself?

DIY difficulty is moderate. Many owners can handle it with a scan tool, a multimeter and basic hand tools. Always confirm the cause before buying parts.

Will C0663 clear itself?

Once the fault is fixed, the check engine light usually goes off by itself after the system passes its self-test over several drive cycles. Clearing the code with a scan tool resets readiness monitors, so an inspection station may turn you away until a full drive cycle is completed.

Code data: OBDex (CC0)