What is pre cat lambda sensor?
Many vehicles now feature a pre-cat Lambda Sensor and a post-cat Lambda Sensor. Whilst the pre-cat Lambda Sensor communicates to the ECU regulating the air/fuel ratio; the post-cat Lambda Sensor performs a diagnostic role, monitoring the Catalytic Converter.
What is the use of lambda sensor in the catalytic converter?
Lambda sensors measure the oxygen content in the exhaust gas. If the signals from the control sensor and monitor probe are too similar, this indicates that almost no exhaust gas purification is taking place in the catalytic converter.
How long do lambda sensors last?
around 93,000 miles
The lifetime of a lambda sensor is around 93,000 miles driven. However, this could be shorter depending on numerous factors that can damage it, mainly because of anomalies coming from the engine. Leaks from the exhaust can also damage the probe.
Where is the pre cat and post cat lambda sensor?
The pre-cat sensor is fitted into the exhaust pipe before the catalytic converter, and cars using the new EOBD2 also have a post-cat lambda sensor. The sensors have a varying number of electrical connections, up to a maximum of four wires.
What is the purpose of the lambda sensor test?
Lambda sensor – pre- & post- catalytic converter. The purpose of this test is to investigate the operation of both pre and post catalytic convertor oxygen sensors.
How does a catalytic converter affect a lambda sensor?
Experiment to test the effect of a catalytic converter on the measurements taken with broad-band Lambda sensors: A test engine was instrumented with Motec (PLM) broadband sensor equipment before and after the catalytic converter (boss’s welded into manifold and an additional tailpipe mounted probe as further reference).
What does a pre cat sensor on a catalytic converter do?
A switching voltage on the post-cat sensor indicates that the gases are passing across the catalytic converter’s ceramic monolith without being subjected to chemical change and therefore the cat requires replacing with a known good unit, providing that the pre-cat waveform is within specification. A typical Zirconia lambda sensor has four wires.
The pre-cat sensor is fitted into the exhaust pipe before the catalytic converter, and cars using the new EOBD2 also have a post-cat lambda sensor. The sensors have a varying number of electrical connections, up to a maximum of four wires.
Lambda sensor – pre- & post- catalytic converter. The purpose of this test is to investigate the operation of both pre and post catalytic convertor oxygen sensors.
Experiment to test the effect of a catalytic converter on the measurements taken with broad-band Lambda sensors: A test engine was instrumented with Motec (PLM) broadband sensor equipment before and after the catalytic converter (boss’s welded into manifold and an additional tailpipe mounted probe as further reference).
A switching voltage on the post-cat sensor indicates that the gases are passing across the catalytic converter’s ceramic monolith without being subjected to chemical change and therefore the cat requires replacing with a known good unit, providing that the pre-cat waveform is within specification. A typical Zirconia lambda sensor has four wires.