EPC LIGHT ?
08-20-2010, 08:45 AM
#3
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Could be completely innocuous. It will happen if the ignition was turned on with one or several various connectors disconnected, such as a manifold flap position sensor, or throttle valve connector on the throttle body and then reconected properly before starting the car. But this usually only happens if you've been working on the car. If this is the case, just clear the DTC's with VCDS and be done with it (assuming the connectors are indeed re-connected properly). It interesting that this scenario will store DTC's for unplausible signal or open circuit and cause an EPC light, but won't cause a CEL. If a connector is unplugged during vehicle maintenance AND LEFT UNPLUGGED when the car is started, then I'm pretty sure you'd get both a EPC and CEL light.
The other more common case is that one of the manifold tumble flap sensors is starting to go bad, in which case there should also be a stored DTC (diagnostic trouble code) referring to the manifold flap, but again, not necessarily a CEL.
You have 2 choices. Take it to a dealer and have them see if there are any DTC's stored in either of the ECU's. Or, go to Ross-Tech and buy VCDS so you can see for yourself whats going on.
The other more common case is that one of the manifold tumble flap sensors is starting to go bad, in which case there should also be a stored DTC (diagnostic trouble code) referring to the manifold flap, but again, not necessarily a CEL.
You have 2 choices. Take it to a dealer and have them see if there are any DTC's stored in either of the ECU's. Or, go to Ross-Tech and buy VCDS so you can see for yourself whats going on.
08-20-2010, 10:09 AM
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Thanks for the very thourough info, The light went out when I started it again. I made the trip into work about 15 miles with it on. Then heading out to starbucks, and noticed it had not come back on. Hmmmmm I have to go have the DRC recall done anyways, so I will drop it at hte dealer.
Could be completely innocuous. It will happen if the ignition was turned on with one or several various connectors disconnected, such as a manifold flap position sensor, or throttle valve connector on the throttle body and then reconected properly before starting the car. But this usually only happens if you've been working on the car. If this is the case, just clear the DTC's with VCDS and be done with it (assuming the connectors are indeed re-connected properly). It interesting that this scenario will store DTC's for unplausible signal or open circuit and cause an EPC light, but won't cause a CEL. If a connector is unplugged during vehicle maintenance AND LEFT UNPLUGGED when the car is started, then I'm pretty sure you'd get both a EPC and CEL light.
The other more common case is that one of the manifold tumble flap sensors is starting to go bad, in which case there should also be a stored DTC (diagnostic trouble code) referring to the manifold flap, but again, not necessarily a CEL.
You have 2 choices. Take it to a dealer and have them see if there are any DTC's stored in either of the ECU's. Or, go to Ross-Tech and buy VCDS so you can see for yourself whats going on.
The other more common case is that one of the manifold tumble flap sensors is starting to go bad, in which case there should also be a stored DTC (diagnostic trouble code) referring to the manifold flap, but again, not necessarily a CEL.
You have 2 choices. Take it to a dealer and have them see if there are any DTC's stored in either of the ECU's. Or, go to Ross-Tech and buy VCDS so you can see for yourself whats going on.
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