Finding the cause of car problems
Computer diagnostics
Has the Check Engine light come on? Is your car hard to start, jerking or behaving differently? Computer diagnostics helps us find where to look for the problem. We check fault messages and how the available systems are working, explain what we find and discuss the next step.
Thematic AI illustration
A warning light has come on
We investigate why the car is showing a warning and where to start looking.
You're buying a used car
We review the available faults and control-unit data. This is helpful, but it cannot reveal the car's entire history.
Before software updates or tuning
We check for existing problems that could interfere with programming.
The problem comes and goes
Stored faults may show what happened. Sometimes we need the fault to happen again to investigate it.
You don't want to replace parts at random
We check whether an expensive component is really faulty or the problem lies in its power or connections.
You want to check the car's condition
We review the warnings and readings your model makes available and explain what they mean.
- 01
Listen and find out what's happening
Tell us when the problem started and how the car behaves. We connect a diagnostic scanner to check available faults in the engine, transmission and other systems.
Show example
CHECKING THE SYSTEMS$ CHECK DEMONSTRATION> ENGINE .......... CHECK> GEARBOX ......... IF FITTED> BRAKES .......... IF AVAILABLE> AIRBAGS ......... IF FITTED$ illustration, not your car's resultsroot@diag-lab:~$ ▌CHECKING THE SYSTEMS$ CHECK DEMONSTRATION> ENGINE .......... CHECK> GEARBOX ......... IF FITTED> BRAKES .......... IF AVAILABLE> AIRBAGS ......... IF FITTED$ illustration, not your car's resultsroot@diag-lab:~$ ▌ - 02
See how the car is working
The scanner displays available readings from the engine and other systems while they run. If needed, we also use instruments to check electrical signals.
Show example
HOW WE CHECK ELECTRICAL SIGNALS5 V/div2 ms/div> EQUIPMENT DEMONSTRATION, NOT A MEASUREMENT OF YOUR CAR
HOW WE CHECK ELECTRICAL SIGNALS5 V/div2 ms/div> EQUIPMENT DEMONSTRATION, NOT A MEASUREMENT OF YOUR CAR
- 03
Check power and connections
If a control unit stops responding or works intermittently, we check its power, fuses, wires and connections. Sometimes a poor connection is the cause, not an expensive control unit.
Show example
WHAT WE MAY NEED TO CHECKPower to the unitMEASUREGround connectionCHECKRelays and wiringCHECKFusesCHECKWHAT WE MAY NEED TO CHECKPower to the unitMEASUREGround connectionCHECKRelays and wiringCHECKFusesCHECK - 04
Look for the cause, not just a fault code
We compare symptoms, fault messages and measurements. A fault code is a clue, but it does not always mean the named component needs replacing.
Show example
FINDING THE CAUSE$ FINDING THE CAUSE> CUSTOMER CONCERN ... REVIEW> FAULT MESSAGES .... COMPARE> FURTHER CHECKS .... AS NEEDED$ example process, not a diagnosisroot@diag-lab:~$ ▌FINDING THE CAUSE$ FINDING THE CAUSE> CUSTOMER CONCERN ... REVIEW> FAULT MESSAGES .... COMPARE> FURTHER CHECKS .... AS NEEDED$ example process, not a diagnosisroot@diag-lab:~$ ▌ - 05
Explain what we found
We explain what we checked, what was unusual and what we recommend next. If more testing or repairs are needed, we discuss them separately.
Show example
WHAT YOU'LL KNOW AFTER THE CHECK[01] WHAT WAS CHECKED
[02] WHAT WE FOUND
[03] RECOMMENDED NEXT STEPS
WHAT YOU'LL KNOW AFTER THE CHECK[01] WHAT WAS CHECKED
[02] WHAT WE FOUND
[03] RECOMMENDED NEXT STEPS
CURRENT READINGS show values sent by the car while it runs. Fault messages are usually stored in memory, while current sensor readings can be watched during the inspection.
We compare readings with the expected values for your particular model. A single number rarely identifies the faulty part.
We may also see SAVED FAULT DETAILS — information about the conditions when a fault occurred, if the car saved it.
For example, a rough-running engine might have an air leak, a fuel delivery problem or a faulty sensor. We investigate likely causes rather than choosing a replacement part from one reading.
Check whether the engine idles smoothly.
Check whether the engine warms up normally.
Review readings if the engine runs roughly.
Check whether the engine is receiving the right airflow.
Readings can help assess fuel-system operation.
Check whether the engine is compensating for a mixture problem.
Check pressure under suitable running conditions.
See how the engine responds to load.
Check the response when the accelerator is pressed.
If available, assess its temperature and operation.
EXAMPLE READINGS — NOT MEASUREMENTS FROM YOUR VEHICLE
Get in touch if
- Check Engine or another warning light comes on
- Your car suddenly uses more fuel
- The engine runs roughly, misfires or jerks
- The automatic gearbox shifts with jolts
- The car accelerates poorly or loses power
- Safety-system warnings appear after an accident
- You are looking at a used car
- You are planning tuning or a software update
What we do during the visit
- Discuss the problem and scan available systems
- Read fault messages and their available details
- Check live readings from relevant systems
- Examine power or wiring when indicated
- Recommend further measurements if needed
- Explain the findings and next steps
A code does not always mean a broken part
The issue may be wiring, power supply or another part of the system.
Some faults only appear occasionally
It may take a check under the conditions where the problem occurs.
A poor connection can cause several faults
We check power and connections before recommending expensive replacement parts.
Not every car provides the same information
Available tests vary by model and equipment.
Old faults may not be current problems
We check whether stored messages are relevant to today's symptoms.
A firm answer isn't always possible immediately
If more evidence is needed, we agree the next investigation instead of guessing.
// SUMMARY: If we cannot confirm the cause in one visit, we explain which further checks would help and why. Extra work is priced separately.
Standard computer diagnostics covers the agreed checks. If we need dismantling, additional measurements or repairs, we'll explain the work and agree the cost first.
Other AUTOLAB services
Ready to start the job?
Describe the problem in the contact form — we reply within a day.