You took the correct action for the limp home mode. Your throttle was shut down by the computers, not the DTSC warning. So something else was at fault, probably the ETM or throttle position sensor.

Remember, 2001 was an early year for the ETM and other computers all communicating with each other. The DIM and CEM are notorious for overheating and blowing resistors or soldering.

As for the DSTC, I found this:

Dynamic Stability Traction Control (DSTC)
The DSTC system performs all of the functions of the STC system. In addition, DSTC also applies the brakes to one or more of the wheels to help maintain stability if a wheel begins to lose traction. The system functions at speeds above 12 mph (20 km/h) and works on all four wheels, on any road surface. When DSTC is active, brake pressure is regulated automatically and the brake pedal will move slightly. If you press the brake pedal while DSTC is automatically regulating brake pressure, it will feel stiffer than normal. A pulsating sound will be audible at this time, which is quite normal.

Switching off DSTC
Normally, DSTC should be switched on at all times. If for any reason the steering wheel position or the front wheels are not properly aligned, DSTC should be switched off since the system may receive incorrect signals.
When the LED in the button is on, this indicates that DSTC is switched on (the light will also come on if a fault has been detected in the system). To avoid inadvertently switching the system off, the button must be pressed for at least one second before DSTC is deactivated.
The symbol will come on to indicate that DSTC has been switched off. The system is automatically switched on when the engine is started.
The DSTC indicator light () will flash when:
DSTC is actively functioning to help avoid loss of traction.
The DSTC indicator light () will stay on when:
The car is started (for approximately 2 seconds as DSTC performs a self-diagnostic test).
DSTC has been switched off by pressing the DSTC button in the middle console.
DSTC has been temporarily switched off due to high brake temperature. The system will automatically switch on again when the brakes have cooled. If the system has been switched off due to a fault. An authorized Volvo retailer should check the system.
--
Keeping it running is better than buying new