Problems of the lambda sensor: symptoms, cost and affected models
We have documented 10 faults of the lambda sensor in 10 engines, affecting 63 models of car in our database. The most important by severity and frequency: faulty catalytic converter and lambda sensors on the 2005-2010 Swift (engine warning light) (1.3, 1.5 and 1.6 gasolina (serie M)), sensor failures: lambda sensor and crankshaft position sensor (TDC) (1.2 8v Fire) and sensors that fail: lambda sensor and temperature sensor (1.4 and 1.6 TU3/TU5).
How it works and why it fails
Lambda sensor
The lambda sensor measures oxygen in the exhaust gases so the ECU can adjust the air-fuel mixture. Engines have one before and one after the catalytic converter. Over time it gets fouled or its heater element fails, and the mixture stops being adjusted properly.
What to do
A faulty lambda sensor usually turns on the engine light and increases fuel consumption. Check the OBD code before replacing it: an exhaust leak or a mixture problem can trigger the same warning. If the sensor is fouled with oil or coolant, the cause is in the engine.
General explanation by MotorFiable. The specific faults of each engine and car, with their sources, are on the linked pages.
Common symptoms
The symptoms that come up most often in the documented faults of the lambda sensor. Open each one to see what other faults cause it.
Problems of the lambda sensor by engine
From most to least important (severity × frequency). Each page details the affected versions and years, symptoms, cost and how to check for it.
- 1Medium severityFrequency: Common1.3, 1.5 and 1.6 gasolina (serie M)Faulty catalytic converter and lambda sensors on the 2005-2010 Swift (engine warning light)On the 2005-2010 Swift the catalytic converter often fails at around 50,000 km according to gebrauchtwagenberater.de, and several 1.6 owners cite the lambda sensor. The warning is the engine light; on the Sport the catalytic converter is integrated with the manifold.
- 2Medium severityFrequency: Occasional1.2 8v FireSensor failures: lambda sensor and crankshaft position sensor (TDC)The 1.2 8v Fire can suffer sensor faults: the lambda sensor (warning light, rough running) and, in the Fiat Punto, the crankshaft position sensor (TDC sensor), linked to misfires. These are minority issues, but they recur across several models with this engine.
- 3Low severityFrequency: Common1.4 and 1.6 TU3/TU5Sensors that fail: lambda sensor and temperature sensorThe lambda sensor and the coolant temperature sensor are, along with the coils, the components most cited as faulty: they cause an unstable idle, the engine warning light coming on or a cooling fan that does not behave normally.Appears at around 25,000 km
- 4Low severityFrequency: Common2.0 and 2.4 VVT-iLambda sensor failure on the 1AZ-FE (RAV4 and Avensis 2.0 VVT-i)Lambda sensors are the part that fails most in the RAV4 2.0 VVTi testimonials (about 20 cases among 75 testimonials) and also appear in those for the Avensis 2.0 VVTi; it is a limited-cost fault, not an engine one.Appears at around 150,000 km
- 5Low severityFrequency: Occasional1.6 DIG-TLambda sensor and other engine sensor failuresAn engine warning light caused by a lambda sensor or other sensor failure is one of the most repeated issues in the owner reviews consulted for this engine, although it is almost always fixed by replacing the sensor, with no damage to the engine.
- 6Low severityFrequency: Occasional1.0/1.2/1.4 EcotecFaulty lambda sensors on the 1.2 and 1.4 petrolOpel's 1.2 and 1.4 petrol engines (Twinport and A series) show faulty lambda sensors on the Corsa C, Corsa D and Astra J. The usual consequence is the engine warning light and a poorer-regulated mixture; it does not affect the mechanics.
- 7Low severityFrequency: Occasional1.4 and 1.6 16vFaulty lambda sensors on the 1.6 16V (K4M)The 1.6 16V K4M (Mégane I, Scénic I, Dacia Duster I) has documented lambda sensors that occasionally fail and trigger the engine warning light. They are replaced without touching the engine and it is not a serious fault.
- 8Low severityFrequency: Occasional1.0 VVT-iFaulty lambda sensor (P0420 code) on the 1.0 VVT-iOn the 1.0 VVT-i (1KR-FE) in the Aygo, C1 and 107/108, the lambda sensor, especially the one upstream of the catalytic converter, is documented as failing at high mileage and leaving code P0420 and the engine warning light. It is a cheap repair and does not damage the engine.
- 9Low severityFrequency: Occasional1.4, 1.6 and 1.8 VVT-iAir mass meter and lambda sensor failuresOn a minority of Corolla, Avensis and Corolla Verso cars with this engine, the air mass meter (MAF sensor) or the lambda sensor gives wrong readings and lights up the engine warning light; it is a relatively simple repair and does not compromise the engine.
- 10Low severityFrequency: Occasional1.4 16v and 1.6 MPI/FSIFaulty lambda sensors on the 1.6 FSIThe 1.6 FSI direct-injection engine (Golf V, Touran) has documented lambda sensor faults that trigger the engine warning light and cause a rough idle. It is a low-severity fault, but it should be fixed to avoid overloading the catalytic converter.
Engines with faults of the lambda sensor
Problems of the lambda sensor by make
Problems of the lambda sensor in your car
1 car has several documented faults of the lambda sensor. Choose yours to see only the ones that affect it, by engine and by year.
Toyota 1
Frequently asked questions
Which engines have the most faults of the lambda sensor?
By severity and frequency, the 1.3, 1.5 and 1.6 gasolina (serie M) (faulty catalytic converter and lambda sensors on the 2005-2010 Swift (engine warning light), medium severity), the 1.2 8v Fire (sensor failures: lambda sensor and crankshaft position sensor (TDC), medium severity), the 1.4 and 1.6 TU3/TU5 (sensors that fail: lambda sensor and temperature sensor, low severity), the 2.0 and 2.4 VVT-i (lambda sensor failure on the 1AZ-FE (RAV4 and Avensis 2.0 VVT-i), low severity), the 1.6 DIG-T (lambda sensor and other engine sensor failures, low severity) and the 1.0/1.2/1.4 Ecotec (faulty lambda sensors on the 1.2 and 1.4 petrol, low severity). In total we have documented 10 engines with faults of the lambda sensor.
What symptoms does a fault of the lambda sensor cause?
The most frequently cited in the documented faults: engine fault warning light (check engine), increase in fuel consumption, gradual loss of power, "pollution control system faulty" message and hard starting or engine will not start.