How much does it cost to repair limp mode?

Limp mode or limp home mode, is your car's way of protecting itself from a minor issue causing a lot of damage. It can be triggered by any number of faults or erroneous sensor readings, meaning it can sometimes be difficult to fix.

In this article, we’ll explore the potential costs of repairing whatever is causing the limp mode and how to investigate further.

How much does it cost to repair a car in limp mode?

Repairing a car in limp mode can cost anything from £45 to £2,000+, depending the cause of the problem. Unfortunately, the cause could be one of hundreds of issues.

The first thing to do is have a diagnostic scan done; some garages will charge around £50 as a starting cost to have the fault codes read. This should tell them what the cause of the problem is.

Below are some common causes of limp mode and their associated repair costs.

• Sensors: £45-£120 – a faulty sensor could cause the ECU to put the car into limp mode

• Turbo pipes: £30-£450 – a split or damaged turbo/intercooler hose will cause the car to go into limp mode. Look out for excessive smoke from the exhaust and a whistling sound

• Fuelling: £70-£600 – a blocked or clogged fuel filter or pump, misfuelling, or a clogged injector could

• Misfire: £60-£700+ – a badly misfiring engine is likely to cause the car to go into limp mode, which could be caused by bad spark plugs, coils, other ignition components or major engine issues

• Air flow meter: £50-£550 – an inaccurate or broken air flow meter will mean the engine is incorrectly fuelling, potentially causing limp mode

• Major engine issues: £700-£2,500+ – a broken timing belt, head gasket failure, or other major issue could be the cause

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What is limp mode or limp home mode?

Limp mode is when a car's ECU temporarily limits the power the engine can produce when a fault is present. The fault is likely to be detected by one or more of the sensors on the engine or exhaust.

In general, a car will have 10-20% of its normal power output whilst in limp home mode, allowing you just enough power to get the car to the side of the road safely.

Why do cars go into limp mode?

There are many faults that can cause a car to go into limp mode, ranging from minor sensor faults to blown engines and other major issues. This is done to protect the engine and other components from further damage.

For example, if the car detects a serious misfire, it will engage limp mode to protect the engine and catalytic converter from the effects of over-fuelling.

How to diagnose a car in limp mode

If the car has gone into limp mode, then the ECU will almost certainly have stored the error code. Connecting to the car via the OBD port with a suitable diagnostic tool will enable the codes to be read.

From there, systems can be further investigated, or parts replaced to fix the root cause of the limp mode event. Once parts have been changed or repaired, the car’s ECU can be cleared of fault codes, removing any warning lights on the dashboard. This also means any existing or new faults will be clearly identifiable.

What causes limp home mode?

Many faults can cause limp mode; it can also be caused by a faulty sensor, despite there not being a fault present at all. Below are some common faults that are likely to cause limp mode, though be mindful that this list is far from exhaustive:

• Faulty oxygen (O₂) sensor

• Mass air flow (MAF) or MAP sensor failure

• Throttle position sensor (TPS) or throttle body fault

• Boost leak

• Wastegate actuator or pressure sensor fault

• EGR valve stuck open/closed

• The diesel particulate filter (DPF) or catalytic converter is clogged

• Knock sensor fault

• Crankshaft or camshaft position sensor fault

• Misfire (coil pack or spark plug failure)

• Fuel pump or pressure regulator failure

• Clogged fuel filter or injector

• Coolant temperature sensor fault

• Overheating engine

• Low oil pressure or oil pressure sensor fault

• Transmission fault

• Torque converter fault

• Transmission fluid is low/overheated

• ABS/traction control fault

• ECU/PCM fault

• Wiring or grounding issue

Can you drive in limp mode?

Only to get the car to a safe place, such as a layby or refuge area on a motorway. In limp home mode, the car will have too little power to drive on the road safely, making roundabouts and junctions very dangerous.

Have the fault repaired with Bumper

Whether the underlying issue is an inexpensive sensor or a major engine issue, it can often mount up to a large repair bill, accounting for diagnostics, parts and labour.

This is where Bumper's car repair loans can help. Choose from hundreds of nationwide garages and spread out your car repair payments.

Author - Joseph Law

Joseph has been writing about cars for over eight years and writing for Bumper for over three, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.