Symptom
Only happens above a certain speed
Nothing at town speeds, and it appears reliably once you are past a particular point — often a motorway cruise, sometimes an exact number the driver has learned. The threshold itself is the clue. Something that starts at one speed and not another is usually driven by a frequency: a wheel or driveshaft turning fast enough to resonate, an aerodynamic load that only exists above a certain pace, or a control strategy the vehicle switches into. Note the number and whether it depends on engine speed or road speed — changing gear to hold the same road speed at different revs separates those two in a single test.
Also described as: only at motorway speed, above 50, only at high speed, happens on the motorway, only when driving fast, only at freeway speed, happens on the freeway, فقط در سرعت بالا, بالای سرعت مشخص, solo a cierta velocidad, pasa a partir de cierta velocidad, solo en autopista, فقط بعد سرعة معينة, على السرعات العالية فقط, عند تجاوز سرعة محددة
Some causes mean you should stop driving
2 of the 16 codes that produce this symptom indicate a fault where continuing to drive risks damage or is unsafe. If the symptom is sudden or severe, treat it as one of those until a scan says otherwise.
What this usually means
The threshold itself is the clue. Something that starts at one speed and not another is usually driven by a frequency — a wheel or driveshaft turning fast enough to resonate, an aerodynamic load that only exists above a certain pace, or a control strategy the vehicle switches into.
Separate road speed from engine speed in a single test, and it costs nothing: hold the same road speed in a different gear. If the fault follows the road speed, it is wheels, tyres, driveline or aerodynamics. If it follows the engine speed, it is the engine or something driven by it. That one observation removes half the candidates before anything is measured.
Frequency-driven faults are the largest group. A wheel imbalance produces a vibration that grows and fades smoothly over a speed range because it passes through a resonance; a worn driveshaft or a failing wheel bearing rises with speed and does not fade. A vibration that arrives and departs at one particular point rather than growing steadily points at a resonance being excited — a heat shield, an exhaust mounting, a trim panel — or at a torque converter lock-up engaging.
Aerodynamic causes are real and get overlooked. A loose undertray, a badly seated bonnet, a roof bar, or a door seal that has come away all produce noise or buffeting that simply does not exist below the speed where airflow matters.
And some thresholds are the car working. Speed-dependent steering weight, a rear spoiler deploying, active grille shutters closing, and stability strategies that change above a set speed all produce a step change that is designed rather than faulty. Note the number: an exact, repeatable speed is more likely a strategy than a resonance.
Working through it
| What you find | Likely cause | How to confirm it | What fixes it |
|---|---|---|---|
| Follows road speed regardless of gear | Wheels, tyres, driveline or aerodynamics — not the engine | Hold the same road speed in a different gear. Fault unchanged means road speed; fault changed means engine speed. One test, half the candidates gone. | Pursue the road-speed population: balance, bearings, driveshafts, or loose bodywork. |
| Vibration grows and fades smoothly over a speed range | Imbalance passing through a resonance — a wheel, a tyre with a displaced belt, or a driveshaft | Balance the wheels and inspect the tyres for irregular wear. Smooth growth and fade is the imbalance signature. | Balance or renew the wheel or tyre; renew a driveshaft where play is found. |
| Arrives and departs at one particular speed | A resonance being excited — a heat shield, exhaust mounting or trim panel — or a lock-up clutch engaging | Touch-test heat shields and exhaust mountings by hand. If it disappears the instant the brake is touched, it is the torque converter lock-up clutch. | Secure or renew the loose component, or diagnose lock-up as the shudder entry in this vocabulary describes. |
| Noise or buffeting only at motorway speed | Aerodynamic — a loose undertray, a seal that has come away, a badly seated bonnet, or roof bars | Inspect the undertray fixings and door and window seals. Removing roof bars for one journey is a free test. | Refit or renew the tray, seal or fixing. This population has no code and no sensor. |
| An exact, repeatable speed with a step change in behaviour | A control strategy — speed-dependent steering, active aerodynamics, grille shutters, or a stability threshold | The precision is the tell: resonances are approximate, strategies are exact. Check the handbook for what changes at that speed. | No repair unless the strategy is misbehaving. Diagnose the named system rather than chasing a vibration. |
| Warning light or cut-out rather than a vibration | A signal that becomes implausible at speed — a wheel speed sensor with a marginal air gap, or a harness under aerodynamic load | Log all four wheel speeds at the threshold. A dropout at one corner names it; four agreeing points elsewhere. | Renew the sensor or repair the harness. Check the reluctor ring before fitting a sensor. |
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Follows road speed regardless of gear
- Likely cause
- Wheels, tyres, driveline or aerodynamics — not the engine
- How to confirm it
- Hold the same road speed in a different gear. Fault unchanged means road speed; fault changed means engine speed. One test, half the candidates gone.
- What fixes it
- Pursue the road-speed population: balance, bearings, driveshafts, or loose bodywork.
-
Vibration grows and fades smoothly over a speed range
- Likely cause
- Imbalance passing through a resonance — a wheel, a tyre with a displaced belt, or a driveshaft
- How to confirm it
- Balance the wheels and inspect the tyres for irregular wear. Smooth growth and fade is the imbalance signature.
- What fixes it
- Balance or renew the wheel or tyre; renew a driveshaft where play is found.
-
Arrives and departs at one particular speed
- Likely cause
- A resonance being excited — a heat shield, exhaust mounting or trim panel — or a lock-up clutch engaging
- How to confirm it
- Touch-test heat shields and exhaust mountings by hand. If it disappears the instant the brake is touched, it is the torque converter lock-up clutch.
- What fixes it
- Secure or renew the loose component, or diagnose lock-up as the shudder entry in this vocabulary describes.
-
Noise or buffeting only at motorway speed
- Likely cause
- Aerodynamic — a loose undertray, a seal that has come away, a badly seated bonnet, or roof bars
- How to confirm it
- Inspect the undertray fixings and door and window seals. Removing roof bars for one journey is a free test.
- What fixes it
- Refit or renew the tray, seal or fixing. This population has no code and no sensor.
-
An exact, repeatable speed with a step change in behaviour
- Likely cause
- A control strategy — speed-dependent steering, active aerodynamics, grille shutters, or a stability threshold
- How to confirm it
- The precision is the tell: resonances are approximate, strategies are exact. Check the handbook for what changes at that speed.
- What fixes it
- No repair unless the strategy is misbehaving. Diagnose the named system rather than chasing a vibration.
-
Warning light or cut-out rather than a vibration
- Likely cause
- A signal that becomes implausible at speed — a wheel speed sensor with a marginal air gap, or a harness under aerodynamic load
- How to confirm it
- Log all four wheel speeds at the threshold. A dropout at one corner names it; four agreeing points elsewhere.
- What fixes it
- Renew the sensor or repair the harness. Check the reluctor ring before fitting a sensor.
Codes that produce this symptom (16)
Listed with the codes that most typically present this way first — the likeliest place to start.
- C0079 Variable Effort Steering Typical of this code Low
- P0339 Crankshaft Position Sensor A Circuit Intermittent Typical of this code Stop driving Critical
- P05AE Active Grille Air Shutter B Performance/Stuck Off Typical of this code Moderate
- P0635 Power Steering Control Circuit Typical of this code Moderate
- P0734 Gear 4 Incorrect Ratio Typical of this code High
- P0784 4-5 Shift Malfunction Typical of this code High
- P0829 5-6 Shift Malfunction Typical of this code High
- P0CA3 DC/DC Converter Step Up Voltage Performance Typical of this code High
- P2586 Turbocharger Boost Control Position Sensor B Circuit Typical of this code High
- P2587 Turbocharger Boost Control Position Sensor B Circuit Range/Performance Typical of this code High
- P2597 Turbocharger Speed Sensor B Circuit Intermittent Typical of this code Moderate
- P2783 Torque Converter Temperature Too High Typical of this code Stop driving High
- U0130 Lost Communication With Steering Effort Control Module Typical of this code High
- U0243 Lost Communication With Parking Assist Control Module B Typical of this code Moderate
- U0319 Software Incompatibility With Steering Effort Control Module Typical of this code Moderate
- U0645 Lost Communication With Active Air Dam Module Typical of this code Low
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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