Touareg: 2005 V6
Join Date: Feb 2014
Second Vehicle: VW 2
Thanked 12 Times in 12 Posts
Intermittent EPC events V6 3.2L - T1 2005
I have had intermittent EPC events, sometimes limp mode sometimes lower performance for about 6 months. CEL was either one of the redundant sensors in the TB or both (limp mode). When temp was lower than 45F never happened would occur more frequently when above 50F. The TB is not even a year old so doubted the sensors were a problem. Thought it might be the wiring and replaced. No change in behavior. Changed the oxygen sensors before the CAT. Car ran better less frequent events and then only angle sensor G188. Changed the sensors after the CAT. Problem has gone away.
Neither of the Oxygen sensors indicated an issue or resulted in a CEL. If the ECM does not get a signal from the precat oxygen sensor will cause an emergency running mode based on engine character map but would expect a CEL concerning the oxy sensor not the TB angle sensors and EPC only.
Main point if you have similar issues might not actually be your throttle body. Did check precat aging and it was less than 0.80 which is substantively less than new 1.99. The learned values were OK. Could not find anything unusual on post CAT sensor.