Ok so I have a 2003 VW Jetta GLS and these are the codes I have
P2181=Engine Coolant System Performance
P0171= Mass vacuum leak
Engine isn't overheating, thermostat needle is at halfway mark. Grabbed upper radiator hose opens when its supposed to so thermostat is operating. Recently changed CTS (coolant temp. sensor) not OEM, ran ok for ~80/90 miles then CEL turned on again. Have to get this fixed my car is 6months past due for registration b/c of this.
As far as the vacuum leak there are no clamps around the hose that plugs into the FPR (fuel pressure regulator) and the hoses that leave the "Y-vacuum pipe thingy next to the valve cover dont have clamps either, so i believe that would solve that but I need to know what else to check.
P2181=Engine Coolant System Performance= from ross-tech:
Check Engine Coolant Temperature Sender (G62)
Check Coolant Thermostat
Check Engine Cooling System
Put the key on, fan speed on 1, and push the a/c switch. Are both fans kicking on? If not, you found the problem.
Put the key on and fan speed on 1 with temperature set to hot. Does heat come out readily from the vents?
No. Probably the water pump is gone.
Yes. Probably the thermostat is gone.
P0171= Mass vacuum leak= lean due to MAF being dirty/faulty or leak in vac system
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