MrT Posted October 3, 2006 Report Posted October 3, 2006 I recently changed my MAF for a new one and all seemed well until my first trip on the motorway. After around 15 miles, the "EPC" warning light came on with the "ESP" warning, there was an immediate drop in power and the gearbox dropped into 4th gear and I could not make it change up or down. I pulled off at the next junction and very fortunately I had my VAG COM lead from when I changed the MAF. I read the errors and had two, 16485 MASS AIR FLOW SENSOR (G70): Implausible Signal and also from the gearbox something similar to "Input Torque Out of Specification". Clearing the MAF error turned off the EPC warning and I cancelled the gearbox fault as well. The "ESP" warning had not cleared but as soon as I connected to the brake system it did. Started off again and exactly the same happened about ten miles later. I still had the old MAF in the back so I swapped it over and all has been fine for the next 600 miles. The are several points here I would like to understand: 1. When the MAF error occured why did the EPC warning come on when in the past the Engine warning indicated a MAF error? 2. Why did the gearbox report an "input torque" error and shift and lock into 4th gear? 3. Why did the "ESP" warning come on when there were no brake error faults? 4. What did the new MAF give an implausible rather than a low or high error? Quote
NikpV Posted October 3, 2006 Report Posted October 3, 2006 Presumably the sudden drop in torque persuaded the ecu to go into 'limp home mode' if the ecu monitors the maf signal changing over time - possibly a sudden change (which this sounds like) may give the implausible signal error rather than the low/high error, I wonder if you hadn't cleared the errors and restarted the engine whether it would have logged a high/low error as well ?? Quote
MrT Posted October 3, 2006 Author Report Posted October 3, 2006 It shows a normal reading at idle, something seems to happen when driving fast. The error does not reset itself after restarting and needs VAG-COM to clear it. My old MAF sometimes gives a low reading which brings on the engine light (but not the EPC) which is why I changed it. I don't know if i got a dud or if aftermarket MAFs are just not up to Bosch standards. Quote
theinsider Posted November 16, 2006 Report Posted November 16, 2006 It shows a normal reading at idle, something seems to happen when driving fast. The error does not reset itself after restarting and needs VAG-COM to clear it. My old MAF sometimes gives a low reading which brings on the engine light (but not the EPC) which is why I changed it. I don't know if i got a dud or if aftermarket MAFs are just not up to Bosch standards. i have a 2001 2.8 auto that has harsh gear changes. Upon some advice i found somewhere i temporarily disconnected the MAF. This made the gear changes far worse. does this mean it is the MAF causing harsh gear changes or not. Also the EPC light is stuck on now even after reconnecting the MAF. What can i do? anybody able to help? the gear changes previously were harsh say 50% of the time they are now harsh 90% of the time. Quote
MrT Posted November 17, 2006 Author Report Posted November 17, 2006 You will have to clear your EPC warning light with either VAG-COM or another engine code tool. I am not sure if disconnecting the battery for a while will reset it or not. Your engine and car could well be stuck in limp home mode now. No doubt the lack of MAF had triggered this alarm. Quote
Vanbursta Posted November 17, 2006 Report Posted November 17, 2006 I'm fairly certain the MAF not being connected will be stored as a fault code, until it's reset by someone (either a professional garage or with Vag-Com), the light will stay on. Quote
theinsider Posted November 19, 2006 Report Posted November 19, 2006 I'm fairly certain the MAF not being connected will be stored as a fault code, until it's reset by someone (either a professional garage or with Vag-Com), the light will stay on. i left the battery disconnected overnight and the light went off. seeing as the car was worse with the MAF disconnected does this definitely mean that the MAF is OK? when the MAF is disconnected the gearbox problem (thumping into gear is worse and more frequent) it seems logical that a MAF on its way out could cause said symptoms. Especially as the gearbox gets a signal from the MAF apparently?? changed the air filter yesterday - was v v dirty. cant say its made the gal run any different though. Quote
theinsider Posted June 2, 2007 Report Posted June 2, 2007 hi Mr T i notice this post was a while ago now - but did you ever sort the MAF problem? getting very similar symptoms on my 2.8V6 auto 2001. was it a faulty MAF - i have tried an after market replacement but still getting same problem. Nearly always after car is fully warm and at high speeds. any help will be gratefully received Quote
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