Diagnostic Functions

This is the exact OEM manual section for the path above. Use the breadcrumb to move up or down the tree until you reach the precise year, make, model, and subsystem you need.

Need a step-by-step guide?

Get an AI-powered repair guide with parts lists, cost estimates, and clear instructions for your 2004 Volvo.

AI Repair Guides





Transmission control module (TCM) diagnostic functions

General




The control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system. This system continuously monitors its own system and the input and output signals.

Diagnostic trouble codes (DTCs)
The control module will store a diagnostic trouble code (DTC) if it detects a fault. If a fault disappears for any reason after the diagnostic trouble code (DTC) has been permanently stored in the control module, information about the fault remains stored in the control module.

Reading and erasing diagnostic trouble codes (DTCs)
Stored diagnostic trouble codes (DTCs) can be read off and erased using this function.
Diagnostic trouble codes (DTCs) can only be erased when all diagnostic trouble codes (DTCs) have been read at least once.

Reading off input and output signals
Using this function, the status of the control module input and output signals can be continuously read off.
For further information about parameters, see Description of parameters Description of Parameters.

Activating components
This function allows components to be activated so that their functions can be checked.
For further information about activations, see Description of activations Description of Activations.

Reading off the control module identification
VIDA identifies the control modules by reading off a number of codes from the control module memory.
The codes contain the following information about the control module:
- the hardware P/N (control modules without software)
- the hardware serial number (control modules without software)
- the software P/N
- the diagnostic software P/N

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro
← Back to Transmission Control Module (TCM)All Makes

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.