Mobile Car Diagnostics Reading — OBD2 Fault Code Reading
A warning light, rough running engine or intermittent fault needs proper diagnosis — not guesswork. We carry professional-grade diagnostic equipment to your home or workplace in Reading and Berkshire, scan every module, read live data, and give you a plain-English explanation of what is wrong and what it will cost to fix.
What Diagnostics Covers
Engine Management System
The engine control unit (ECU) monitors hundreds of sensors and stores fault codes when readings fall outside expected ranges. Common codes include:
- P0300–P0308 — Engine misfire (specific to cylinder or random)
- P0171 / P0174 — System lean (intake leak, MAF sensor fault, fuel pressure)
- P0420 — Catalytic converter efficiency below threshold
- P0101 — Mass air flow sensor performance
- P0113 / P0118 — Intake air or coolant temperature sensor faults
We read the code, check the freeze frame data (conditions when it triggered), and measure live sensor readings to confirm the root cause.
ABS and Brake System Modules
ABS faults are not readable by standard OBD2 scanners. We access the ABS module directly to read wheel speed sensor faults, hydraulic unit codes and pump motor issues.
Airbag and SRS System
An airbag warning light means the supplemental restraint system has a stored fault. This cannot be cleared without finding and resolving the underlying cause — an airbag that has been partially deployed, a faulty clock spring, seat belt pre-tensioner fault or impact sensor.
Transmission
Automatic gearbox faults — harsh shifting, stuck in limp mode, gear ratio errors — are diagnosed via live transmission data including fluid temperature, solenoid operation and torque converter lockup.
TPMS (Tyre Pressure Monitoring)
TPMS faults can indicate a flat tyre, a faulty sensor or a sensor that needs reprogramming after a tyre change. We read the system and identify which sensor is causing the fault.
Live Data Analysis
Fault codes are a starting point, not a final answer. Many faults only become clear when reading live sensor data with the engine running:
- Oxygen sensor switching frequency and voltage
- Fuel trim short-term and long-term values
- Ignition timing and knock retard
- Idle control valve position
- Throttle body response
For intermittent faults, we can log data during a test drive and replay the recording to find the moment the fault occurs.
Diagnostic Pricing
| Service | Price |
|---|---|
| Full multi-system scan + report | from £45 |
| Scan + live data analysis + written report | from £65 |
| Diagnostic + repair (fault fixed same visit) | Labour quoted before work starts |
The diagnostic fee is credited against any repair carried out during the same visit.
After the Diagnostic
We provide a written report listing every fault code found, its plain-English meaning, our assessment of the likely cause, and our recommendation. You choose whether to proceed with the repair — there is no obligation.
Call 07305 523333 or use the contact form to book a diagnostic visit anywhere in Reading or Berkshire.
Areas we cover
- Mobile mechanic in Reading
- Mobile mechanic in Wokingham
- Mobile mechanic in Newbury
- Mobile mechanic in Basingstoke
- Mobile mechanic in Bracknell
- Mobile mechanic in Tilehurst
- Mobile mechanic in Caversham
- Mobile mechanic in Earley
- Mobile mechanic in Woodley
- Mobile mechanic in Henley-on-Thames
- Mobile mechanic in Twyford
- Mobile mechanic in Thatcham
Frequently asked questions
What does a car diagnostic check cover? +
A professional car diagnostic scan reads fault codes from the engine, gearbox, ABS, airbag and body control modules. We also analyse live sensor data — oxygen sensors, fuel trims, misfire counters, MAF readings — to pinpoint the root cause, not just the symptom.
Is a diagnostic scan the same as clearing fault codes? +
No. Clearing codes without diagnosis is not a repair — the underlying fault remains and the code will return. We carry out a full analysis of what triggered the code and the relevant live data before recommending any repair.
My warning light came on but the car drives fine — should I still get a diagnostic? +
Yes. Many fault codes are stored before a problem becomes driveable. An engine management light for an oxygen sensor fault, for example, may not affect driveability immediately but will worsen fuel economy and eventually cause catalytic converter damage if left.
Which diagnostic tool do you use? +
We use a professional-grade multi-system scanner (Autel or Launch) that accesses all modules — not just the OBD2 port that generic Bluetooth readers use. This means we can read ABS, airbag, transmission, TPMS and body control faults that consumer tools miss.