1998 Volvo C70

1st step should be to check for codes
need to have a scanner tool to be able to check ABS codes
you can access the ECU codes using an OBDII reader

most systems require certain volts to operate and function correctly a low volts or fluctuation in charging system may cause it to act up
check alternator generator and charging system too

Connect a voltmeter between generator B+ terminal and ground. Voltmeter should indicate battery voltage.
If battery voltage is not indicated, check wiring between generator and battery.
Turn ignition on and ensure generator indicator light comes on. If light does not come on, check wiring between generator and warning light.

Connect a voltmeter between positive battery terminal and generator B+ terminal. Start engine and run at 2000 RPM. Turn on headlights, rear window defogger and heater blower.
If voltage drop is more than.2 volt, check circuit between generator B+ terminal and starter for corroded or loose connections. Also, check circuit between starter and positive battery terminal.

Connect a voltmeter between negative battery terminal and generator housing. Start engine, and run it at 2000 RPM. Turn on headlights, rear window defogger and heater blower.
If voltage drop is more than.2 volt, check battery terminals, chassis grounds and engine grounds for corroded or loose connections.

Ensure connections at battery, generator, and starter are clean and tight.
Ensure generator, engine and body are properly grounded.
Ensure generator drive belt is tight and in good condition.
Connect ammeter following manufacturer's instructions. Connect voltmeter leads to battery terminals. Run engine to 2000 RPM. Adjust carbon pile on tester until voltmeter reads 12 volts. Generator output should be 49-55 amps (55-amp generator), 63-75 amps (75-amp generator), 71-80 amps (80-amp generator), 81-120 amps (120-amp generator). If generator output is low, replace generator.

The reading on the charging system is OK to pass basic testing, and test should be directed towards the codes
p0103 Mass Volume Air Flow Circuit High Input
Try to clean it they sell special cleaner in a can
Possible Cause
Signal too high:
Short to supply in signal cable.
Open circuit in cable to signal or power ground.
Defective mass air flow (MAF) sensor.
Contact resistance in terminals.
Signal too low:
Defective fuse 11B/2 (underhood fuse/relay box).
Open circuit in signal or power cable.
Short to ground in signal cable.
Fresh air hose damaged or loose.
Defective mass air flow (MAF) sensor.
Contact resistance in terminals.

P0116 Engine Coolant Temp Circuit Range
Possible Causes (Faulty Signal)
Defective engine coolant temperature sensor.
Defective coolant thermostat.
Contact resistance in terminals.
Short to another cable in signal circuit.

For the ABS, Tracs light, very common problem will be a bad ABS unit. This could also be affecting your speedometer. As for the other codes, proper diagnosing should be done. One thing you may want to check before replacing the mass air flow sensor is if you have any vacuum leaks? For the coolant temp circuit range, I would suspect a faulty thermostat. Could be partially open or could be opening up to slow?