P1624 Audi Code - Malfunction Indicator Lamp Request Signal Active

P1624 indicates that the Malfunction Indicator Lamp (MIL) Request Signal is active, meaning a secondary issue has been detected by another module and reported to the engine control module (ECM).

Common symptoms include the check engine light being illuminated and potentially reduced engine performance, depending on the underlying issue triggering the MIL request.

P1624 is usually caused by a fault in another control module, such as the transmission control module (TCM) or ABS module, which signals the ECM to activate the MIL.

While rare, a faulty or miscommunicating ECM could cause code P1624, but it's more often related to issues in other modules or wiring.

Diagnosing P1624 involves scanning all vehicle modules for additional codes to identify the root issue and checking for wiring or communication faults between the modules.

You may be able to drive the vehicle, but it’s recommended to diagnose and repair the issue promptly to avoid potential damage or worsening of underlying problems.

Fixing P1624 typically requires addressing the underlying issue in the module that triggered the MIL request, such as repairing a fault in the TCM or ABS system.

It can be related to the transmission if the TCM is sending the MIL request signal, but other systems could also be the cause.

Clearing the code may turn off the MIL temporarily, but the underlying issue must be resolved to prevent the code from returning.

The repair cost depends on the root cause of the MIL request signal, ranging from minor wiring repairs to module replacement, which can vary widely in price.