Sensor Testing
Also called sensor checking
Sensor testing measures what a sensor is actually reporting and compares it against what it should be reporting under the same conditions. It covers oxygen, airflow, temperature, position, pressure and speed sensors. The point is to separate three different causes that all set the same code: a failed sensor, a wiring or connector fault, and a sensor correctly reporting a real problem elsewhere. Testing is a diagnosis. It will not fix anything, but it stops good parts being replaced.
Signs you need this
- A fault code naming a sensor, especially one already replaced once
- Rough running, poor economy or hesitation with no obvious cause
- A gauge or reading on the dashboard that is clearly wrong
- The car starts then stalls, or runs badly only when hot or cold
- A repair elsewhere replaced a sensor and the fault came back
Not all of these have to be present, and one of them on its own can mean something else entirely. That is what the diagnosis is for.
What the job includes
- Live data captured for the suspect sensor during a road test
- Supply voltage, earth and signal measured at the sensor connector
- Signal waveform checked where the sensor type requires it
- Comparison against specification or against a matching sensor on the same engine
- Connector and wiring inspected for corrosion, chafing and pin tension
- Written finding stating whether the sensor, the wiring, or the condition is at fault
How we do it
Establish the expected value
We look up what this sensor should read for your engine at the temperature, load and speed being tested.
Capture live readings
Data is logged during a road test, since many sensors only drift out of range under load or heat.
Test the circuit
Supply, earth and signal are measured at the connector to separate a sensor fault from a wiring fault.
Compare and verify
Readings are compared against specification or a matching sensor, which exposes a sensor drifting without setting a code.
State the finding
You are told which of the three causes applies, with the measured evidence, and what the repair would involve.
How we work
The same on every job, which is why we can write it down.
Diagnosis before quote
We find the fault first. A price given over the phone for a noise nobody has heard is a guess.
The price is agreed first
You approve the work and the cost before a spanner is picked up. Extra work means another call.
Parts you can check
We tell you whether a part is genuine, OEM, aftermarket or used, and what each one costs.
Old parts returned
Ask and we will hand back whatever we replaced. It is the simplest proof that the job was done.
Book sensor testing
Fill this in and a person will call you back to confirm the time and the price. Only your name and one way to reach you are required.
You send this
Takes a minute. No payment, no obligation.
We call you
To confirm the car, the time and the location.
Tell us the car and the symptom
We will arrange a mechanic at your location, or a slot at the nearest workshop. No payment until the price is agreed.