270 cycles ago, if you start your car 10-15 times a day thats 20-30 days since it came on, and cycle=on off, so each crank adds to it. IIRC the code tracks from initial setting off not every time. So if you've had the problem about 2-3 weeks that would make sense. You might try throwing the car in neutral when running, hitting the pedal just to see how high it revvs. Don't go past redline but if it stops around 4-5k it could be the rpm sensor... There is an RPM sensor on the top of the bell housing of your transmission so you might want to check it for connection and whatnot..


Here's what volvo says on that code...

Condition

The control module calculates the number of teeth on the flywheel using the engine speed (RPM) sensor. Diagnostic trouble code (DTC) ECM-5200 is stored if the control module detects at least one tooth too many (Signal too high) or one tooth too few (Signal too low).
The control module detects the position of the flywheel for top dead centre (TDC) using the signal from the speed sensor. Diagnostic trouble code (DTC) ECM-5200 is stored if the control module is unable to detect top dead centre (TDC) on the flywheel (Faulty signal) or if the reference position for TDC is missing sporadically.


Substitute value
-The control module uses the signal from the camshaft position (CMP) sensor if the camshaft position (CMP) sensor has been adapted
-Variable valve timing control is blocked
-Engine speed (RPM) is limited.


Possible source

Signal too high:
-Signal interference.
Signal too low:
-Incorrectly installed engine speed (RPM) sensor
-Defective flywheel or ring gear.
Faulty signal:
-Signal interference
-Contact resistance in the terminals
-Incorrectly installed engine speed (RPM) sensor
-Intermittent faults in the wiring for the engine speed (RPM) sensor.
Signal missing:
-Signal interference
-Contact resistance and oxidation.


Fault symptom[s]
-Engine difficult to start
-Poor drivability.