C003A

Not individually documented

C003A is a standardised code, but it is not one of the codes with a single agreed description. Rather than guess at a meaning, this page gives what its structure genuinely tells you and what we see when it turns up in real work.

What the code tells you on its own

System
Chassis

Braking, ABS/ESP, steering, suspension and wheel-speed sensing.

Failure type byte, when the tool sends one
07 (Mechanical failure)

Scan tools report the same fault as C003A and as C003Axx, where xx is a sub-type. They are one fault, and whether the sub-type appears at all depends on the tool and the protocol rather than on the car.

Diagnostics

What we see when C003A turns up

Measured across the diagnostics run through Wrenchlane, not taken from a reference table. Figures as of 2026-10-06.

Diagnostics
2

July 2026 to August 2026

Separate workshops
2

Not one shop meeting it repeatedly

Arrived code only
0%

No symptom description entered at all

Most common marque
Volvo

Where we have seen it most

These are counts from our own work, not a claim about how common the fault is across all vehicles. They describe what independent workshops brought to us, which is a narrower and more specific thing.

FAQ

Frequently asked questions

How do I run a diagnosis?

Select the vehicle on Start, click the Diagnostic card and choose New diagnostic. Fill in the description, the error codes and the mileage, then click Analyze.

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Do I have to type the codes from my scan tool?

No. Click the camera button next to Error codes and take or choose a photo of the scan tool's screen; WrenchLane reads the codes and their descriptions into the form. You can also speak them with the microphone.

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Are the public fault code pages built from my diagnostics?

They use diagnostics run in WrenchLane, with no workshop, customer, registration number or VIN shown. Each fault code page shows how often the code was seen and in how many workshops.

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Run C003A against the car in front of you

Enter the code and the symptoms and get ranked probable causes for that specific vehicle, with the checks in the order worth doing them. Free account, no card.