Is it safe to drive with the power steering warning light on?

You keep control of the car, but it becomes hard work. On the electric power steering systems fitted to ordinary road cars there is still a mechanical connection between the steering wheel and the road wheels, so losing assistance makes the steering very heavy rather than making it stop working. The practical risk is that you cannot turn quickly enough in an emergency, and parking becomes a real effort. Drive straight to a garage, avoid busy manoeuvring, and do not plan a long journey on it.

Why is my steering heavy at low speed but normal at high speed?

Because that is how much assistance the system was providing at each speed. Power steering deliberately gives a lot of help at parking speeds, where you are turning the wheel a long way against stationary tyres, and very little at motorway speed, where light steering would feel nervous. When the assistance fails you lose the large amount at low speed and almost nothing at high speed, so the car feels near normal on the open road and immovable in a car park.

Can a weak battery cause an electric power steering fault?

Yes, and it is worth ruling out before spending on a column. The steering motor draws a substantial current, particularly during parking manoeuvres, and the system monitors its supply voltage closely. If the battery is tired or the alternator is not keeping up, the voltage sags when the motor pulls hard and the module shuts the assistance down to protect itself and the battery. Cars showing intermittent heavy steering on cold mornings are very often describing a battery problem rather than a steering one.

Will an EPS fault fail an MOT?

Yes. An electric power steering warning lamp indicating a malfunction is a major defect, recorded 205 times in the DVSA data this site holds. The number is small because relatively few cars with electric steering are old enough for it to appear often, not because the rule is lenient. The tester also checks steering effort and free play by hand, so steering that has become notably heavy may draw scrutiny in its own right.

Chassis code · standard

C0720Electric power steering torque sensor fault

Standard definition: Electric Power Steering Torque Sensor Circuit

Last updated 27 July 2026

Quick answer

The sensor that measures how hard you are turning the steering wheel has failed or lost its signal. Without it the system cannot decide how much help to give, so it withdraws assistance and the steering becomes very heavy.

How the car works this out

Electric power steering works by measuring the twist you apply to the steering column through a torque sensor, and driving a motor to match. That sensor is the system's primary input, so it is monitored closely: the module checks its supply, its signal range, and on most systems it uses two independent sensing elements and compares them. C0720 is set when the signal is missing, out of range, or the two elements disagree. Since applying assistance based on a wrong torque reading could steer the car by itself, the module's response is to shut the assistance off completely — an intentional fail-safe, not a further failure.

What you might notice

Steering suddenly becoming very heavy, worst at parking speeds and almost normal at motorway speed
Power steering warning lamp on, often in red or amber depending on the car
Assistance returning after switching the ignition off and on, then disappearing again
A clicking or notchy feel through the wheel
Stability control lamp on as well on some cars

What causes it

Most likely first. A code names the check that failed, not the part that failed it, so more than one of these can produce the same number.

1A failed torque sensor within the steering column assemblyCommon
2Moisture ingress into the column unit, often from a leaking windscreen seal, a blocked scuttle drain or a wet footwellCommon
How to check: Check the driver's footwell carpet for damp and look for evidence of water tracking down the column. Water is a very common killer of column-mounted electronics.
3A corroded or disturbed connector at the column, sometimes after airbag, stereo or dashboard workPossible
4Low system voltage, which makes electric steering drop out because the motor draws a heavy currentPossible
How to check: Have the battery load tested and the charging voltage measured. Electric steering is one of the first things to fail on a car with a tired battery.
5A fault within the steering control module that reads the sensorPossible
6Damage from a kerb strike or an accident affecting the columnLess common

What to do about it

1Understand what you have lost before you drive. The steering still works mechanically; it is the assistance that has gone, so the car is heavy rather than uncontrollable. Parking and slow manoeuvres are where you will notice it most.
2Have the battery and charging system checked first. Electric steering draws a lot of current and is quick to shut down on a weak supply, and that is far cheaper to fix than a column.
3Look for water. Damp carpets, a blocked scuttle drain or a leaking windscreen seal are common causes and will destroy a replacement unit as surely as they destroyed the first.
4Ask whether the torque sensor is available separately. On some systems it is, and on others the whole column or steering rack assembly is the only option, which is one of the dearer repairs on the car.
5Expect the replacement to need coding and calibrating to the car.

Can you keep driving?

Only to a garage

On the electric steering systems fitted to ordinary cars, the mechanical connection between the wheel and the road wheels remains, so you keep full control — the steering simply becomes very heavy, as it would on an old car without power steering. The danger is not loss of control but loss of speed of response: manoeuvring in a car park, making a sudden avoiding movement or reacting to something at a junction all take much more effort and time. Drive it directly to a garage and take it steadily.

Will it fail an MOT?

An electric power steering warning lamp indicating a malfunction is a major defect, with 205 recorded failures in the DVSA data behind this site. That figure is strikingly low next to the braking and airbag lamps, and the reason is simply age: electric steering is a relatively recent fitment and the population of cars old enough to be caught by it is still small. It will grow. Separately, the tester assesses the steering for excessive effort, free play and component condition, so a fault heavy enough to change how the steering behaves may attract attention beyond the lamp itself.

The light this turns on

Power steering warning lightThe power steering system has reported a fault and the assistance may be reduced or switched off entirely. You have not lost steering — there is still a mechanical link from the wheel to the road wheels — but the car will feel heavy, and heaviest of all at parking speeds where you need the help most.

Common questions

Is it safe to drive with the power steering warning light on?: You keep control of the car, but it becomes hard work. On the electric power steering systems fitted to ordinary road cars there is still a mechanical connection between the steering wheel and the road wheels, so losing assistance makes the steering very heavy rather than making it stop working. The practical risk is that you cannot turn quickly enough in an emergency, and parking becomes a real effort. Drive straight to a garage, avoid busy manoeuvring, and do not plan a long journey on it.
Why is my steering heavy at low speed but normal at high speed?: Because that is how much assistance the system was providing at each speed. Power steering deliberately gives a lot of help at parking speeds, where you are turning the wheel a long way against stationary tyres, and very little at motorway speed, where light steering would feel nervous. When the assistance fails you lose the large amount at low speed and almost nothing at high speed, so the car feels near normal on the open road and immovable in a car park.
Can a weak battery cause an electric power steering fault?: Yes, and it is worth ruling out before spending on a column. The steering motor draws a substantial current, particularly during parking manoeuvres, and the system monitors its supply voltage closely. If the battery is tired or the alternator is not keeping up, the voltage sags when the motor pulls hard and the module shuts the assistance down to protect itself and the battery. Cars showing intermittent heavy steering on cold mornings are very often describing a battery problem rather than a steering one.
Will an EPS fault fail an MOT?: Yes. An electric power steering warning lamp indicating a malfunction is a major defect, recorded 205 times in the DVSA data this site holds. The number is small because relatively few cars with electric steering are old enough for it to appear often, not because the rule is lenient. The tester also checks steering effort and free play by hand, so steering that has become notably heavy may draw scrutiny in its own right.

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