Car was running very good the last couple of months after replacing ABS sensor and axle half shaft drivers side and resetting computer. By mechanic, I do not have a OBM II reader can someone recommend a good one to read codes and reset codes on a Volvo, would a dead battery cause vehicle to go into limp mode? Nothing else on the computer scan AAA did actually told me what is wrong with car! Could be ECM they said

 

yes low system voltage can put the car into limp mode. Did you measure the battery voltage?

 

Yes I did 10.7 volts would charge to 13 than drop back down to 10.7

 

time for a new battery :-) anything under the low 12s will cause computer and sensor errors... Normal is around 12.6V+ for a fully charged battery