WiteWulf
01-03-2025, 01:54 PM
Hi folks, I'm new here, so hello!
I recently acquired a 2014 A6 Avant C7 SE Ultra 2.0TDI (140kW/190HP). The car has 166k on the clock, but the previous owner destroyed the engine (cheap timing belt failed, valves met cylinders) and I bought it from a relative's garage that had fitted a second hand engine with 52k on it. New timing belt, pulleys, tensioner and water pump were fitted at the same time. The car exhibited a number of Exhaust Gas Recirculation (EGR) problems after the replacement engine was fitted, but these were resolved before I bought it.
The car runs very smoothly, with no reoccurrence of the EGR problems, but I have frequent and easily reproducible P0101 MAF (Mass Air Flow) and P0111 IAT (Intake Air Temperature) range/performance errors.
I drive relatively sedately, but when accelerating away from traffic lights, or up a motorway slip road or hill for more than 5 seconds or so, I'll often get the flashing glow plug lamp on the dash (which disables the auto stop start). I may be imagining it, but it seems more frequent in colder weather. This will clear after stopping and restarting the engine. Reading off error codes with Torque Pro and an OBD interface shows nothing after this has happened.
Less often I will get the engine warning lamp lit (almost always after a flashing glow plug lamp, but once without). This does not clear after an engine restart, and reading off error codes gives one or both of:
P0101 - Mass or Volume Air Flow circuit range/performance error
P0111 - Intake Air Temperature range/performance error
I am able to clear these codes with Torque Pro and the car never seems to go into limp home mode, for what it's worth.
NB. the MAF sensor was replaced as part of the work to resolve the EGR problems (high and low pressure EGR valves also replaced, not cleaned).
There errors seem to be relatively common on Audi owner forums, but I wondered if, with the additional information given above, someone might be able to offer advice on this specific case?
Some posts seem to suggest that IAT sensing is a function of the MAF sensor on these engines, while others state that it's a separate sensor, or in one of the MAP sensors. School physics tells me that temperature and pressure are linked; if the engine is getting an incorrect air temperature reading this could throw the pressure reading/calculations out of whack. With my symptoms seeming to occur more frequently on cold mornings, could this be linked?
There are also a high number of threads with people failing to locate the MAP sensor. Some models of car appear to have more than one. I've located a boost/MAP sensor mounted on a bracket above and to the rear of the engine (part number 04L 145 049 F). Is this the one involved in these errors?
I recently acquired a 2014 A6 Avant C7 SE Ultra 2.0TDI (140kW/190HP). The car has 166k on the clock, but the previous owner destroyed the engine (cheap timing belt failed, valves met cylinders) and I bought it from a relative's garage that had fitted a second hand engine with 52k on it. New timing belt, pulleys, tensioner and water pump were fitted at the same time. The car exhibited a number of Exhaust Gas Recirculation (EGR) problems after the replacement engine was fitted, but these were resolved before I bought it.
The car runs very smoothly, with no reoccurrence of the EGR problems, but I have frequent and easily reproducible P0101 MAF (Mass Air Flow) and P0111 IAT (Intake Air Temperature) range/performance errors.
I drive relatively sedately, but when accelerating away from traffic lights, or up a motorway slip road or hill for more than 5 seconds or so, I'll often get the flashing glow plug lamp on the dash (which disables the auto stop start). I may be imagining it, but it seems more frequent in colder weather. This will clear after stopping and restarting the engine. Reading off error codes with Torque Pro and an OBD interface shows nothing after this has happened.
Less often I will get the engine warning lamp lit (almost always after a flashing glow plug lamp, but once without). This does not clear after an engine restart, and reading off error codes gives one or both of:
P0101 - Mass or Volume Air Flow circuit range/performance error
P0111 - Intake Air Temperature range/performance error
I am able to clear these codes with Torque Pro and the car never seems to go into limp home mode, for what it's worth.
NB. the MAF sensor was replaced as part of the work to resolve the EGR problems (high and low pressure EGR valves also replaced, not cleaned).
There errors seem to be relatively common on Audi owner forums, but I wondered if, with the additional information given above, someone might be able to offer advice on this specific case?
Some posts seem to suggest that IAT sensing is a function of the MAF sensor on these engines, while others state that it's a separate sensor, or in one of the MAP sensors. School physics tells me that temperature and pressure are linked; if the engine is getting an incorrect air temperature reading this could throw the pressure reading/calculations out of whack. With my symptoms seeming to occur more frequently on cold mornings, could this be linked?
There are also a high number of threads with people failing to locate the MAP sensor. Some models of car appear to have more than one. I've located a boost/MAP sensor mounted on a bracket above and to the rear of the engine (part number 04L 145 049 F). Is this the one involved in these errors?