Coast Down Procedure - Misfire Factor Corrections
Registered User
Joined: Oct 2015
Posts: 367
From: USA
Rep Power: 32
From what irish07 told me after changing my clutch, any OBD scanner that can show readiness flag status will work. He told me that if the misfire monitor readiness flag is set, then the factors are learned. Having the readiness flag not set will not show a CEL and it may not cause you to fail emissions testing since most states allow you to have one or two flags not set. I use an OBDLink MX dongle with my Android phone.
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Joined: Oct 2015
Posts: 1,560
From: Ottawa, Ontario, Canada
Rep Power: 98
I read the same thing from irish07 but in my OBD2 scanner (Innova 3100i) it shows the MIS flag Monitor Status as being green but the dealer last week told me that I needed to get the Misfire Monitoring done which means that either the dealer is not telling me the truth or my OBD2 is reporting wrong.
Registered User
Joined: Oct 2015
Posts: 1,560
From: Ottawa, Ontario, Canada
Rep Power: 98
I do believe that the dealer is correct and that my OBD2 is not reporting correctly as I can't even select Aston Martin. I have tried to use Ford and Volvo but I get the same answer, so I will run through the procedures myself but to confirm it has been done correctly I will bring the car to the dealer. I suggest that other who believe their OBD2 is reporting correctly confirm with the dealers that the misfire monitoring is actually ON.
Jeff335i, can you select Aston Martin Vantage V8 4.7l using your OBDLink MX dongle??
Jeff335i, can you select Aston Martin Vantage V8 4.7l using your OBDLink MX dongle??
Registered User
Joined: Oct 2015
Posts: 367
From: USA
Rep Power: 32
My OBD software automatically selects the protocol, etc. It doesn't offer a way to select a different vehicle.
I don't trust my closest dealer AT ALL. I have several service orders from my car's previous owner where the dealer's diagnosis shows they are either 100% incompetent or 100% lying - for $169/hour! They also gave me misinformation when I was looking to get my clutch replaced.
Here's a page about reconnecting the battery from the workshop manual. I put a red box around the part that says the vehicle will eventually re-learn its adaptations. But there is stuff in the manual that is wrong, too. So who knows!
I don't trust my closest dealer AT ALL. I have several service orders from my car's previous owner where the dealer's diagnosis shows they are either 100% incompetent or 100% lying - for $169/hour! They also gave me misinformation when I was looking to get my clutch replaced.
Here's a page about reconnecting the battery from the workshop manual. I put a red box around the part that says the vehicle will eventually re-learn its adaptations. But there is stuff in the manual that is wrong, too. So who knows!
Registered User
Joined: Oct 2015
Posts: 367
From: USA
Rep Power: 32
I got mine from Amazon. The dongle comes with software for Android and for Windows. I use their Android app. The dongle will also work with any other app that can use a bluetooth OBD dongle.
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Joined: Jun 2025
Posts: 155
From: Almassora
Rep Power: 0
IRISH IS THE MAN!!!!
I sent a PM to Irish as follows:
-------------------------------------------
Hey, Irish..
I've been looking at 6SpeedOnline for an hour and I’m getting bits and pieces but I need to confirm something with you. Once I confirm it, I will post it so somebody else like me doesn't bother you with the same question.
I have an 07 DB9 Sport Auto (although from what I read, its the same procedure for a stick)
I am replacing the battery (what a shock eh?)
The "Coast Down Procedure" is:
1. Car needs to be at operating temp.
2. Drive car safely up to 70mph, with the a/c off, in "D"' or manual allowing car to reach 6th gear.
3. Once 70mph is reached, allow car to coast to 30mph, without hitting the brakes or turning the steering wheel more that 10 degrees
4. Repeat 2 & 3
5. Repeat 2 & 3
6. Repeat 2 & 3 (4 times total with no detection equipment)
NOTE 1: If you hit the brakes anywhere during the process, it will abort the sequence. That process won't count and you will need to do it again. With your experience, 4 successful procedures "should" relearn the sequence. You won't know unless AM dealer checks.
NOTE 2: With a battery replacement, you will need to reset radio pre-sets, window dip, and seat memory.
Do I have it right?
-----------------------------------
Irish replied:
Yep, that's good.. The coast down is actually called "Misfire Factor Corrections" ..attempts required depends on coasting speed, coasting on a flat grade learns faster, if on a upward/downward grade it will take a few more than normal to learn
Irish
I sent a PM to Irish as follows:
-------------------------------------------
Hey, Irish..
I've been looking at 6SpeedOnline for an hour and I’m getting bits and pieces but I need to confirm something with you. Once I confirm it, I will post it so somebody else like me doesn't bother you with the same question.
I have an 07 DB9 Sport Auto (although from what I read, its the same procedure for a stick)
I am replacing the battery (what a shock eh?)
The "Coast Down Procedure" is:
1. Car needs to be at operating temp.
2. Drive car safely up to 70mph, with the a/c off, in "D"' or manual allowing car to reach 6th gear.
3. Once 70mph is reached, allow car to coast to 30mph, without hitting the brakes or turning the steering wheel more that 10 degrees
4. Repeat 2 & 3
5. Repeat 2 & 3
6. Repeat 2 & 3 (4 times total with no detection equipment)
NOTE 1: If you hit the brakes anywhere during the process, it will abort the sequence. That process won't count and you will need to do it again. With your experience, 4 successful procedures "should" relearn the sequence. You won't know unless AM dealer checks.
NOTE 2: With a battery replacement, you will need to reset radio pre-sets, window dip, and seat memory.
Do I have it right?
-----------------------------------
Irish replied:
Yep, that's good.. The coast down is actually called "Misfire Factor Corrections" ..attempts required depends on coasting speed, coasting on a flat grade learns faster, if on a upward/downward grade it will take a few more than normal to learn
Irish
Registered User
Joined: Nov 2019
Posts: 3
From: Essex
Rep Power: 0
Still coasting!
Thank you all for great detailed information.
I have just completed replacement of plugs, to NGK iridium, OEM 3 pin coil packs and PCV valves on my 2006 DB9 with 50,000 that I’ve owned from new and this is the first time they’ve been replaced.
I had the error on my Foxwell NT 530-plus showing 8 cylinder ECM bank 1 & 12 cylinder EMS on bank 1 and 12 cylinder EMS 12 on bank 2.
After one rundown I have cleared the bank 2 error but after further try’s still have the bank 1’s.
I’ll now look for the 36-1 profile setting and hopefully get everything sorted - just have to wait until late evening to get a clear bit of road.
Thanks again.
BTW: anyone about to replace the PCV’s - DON’T buy on eBay for £150 each or 2 from HWM at an eye watering £850 - I bought 2 in the USA for $76.
Peter.
I have just completed replacement of plugs, to NGK iridium, OEM 3 pin coil packs and PCV valves on my 2006 DB9 with 50,000 that I’ve owned from new and this is the first time they’ve been replaced.
I had the error on my Foxwell NT 530-plus showing 8 cylinder ECM bank 1 & 12 cylinder EMS on bank 1 and 12 cylinder EMS 12 on bank 2.
After one rundown I have cleared the bank 2 error but after further try’s still have the bank 1’s.
I’ll now look for the 36-1 profile setting and hopefully get everything sorted - just have to wait until late evening to get a clear bit of road.
Thanks again.
BTW: anyone about to replace the PCV’s - DON’T buy on eBay for £150 each or 2 from HWM at an eye watering £850 - I bought 2 in the USA for $76.
Peter.
Registered User
Joined: May 2022
Posts: 101
From: San Diego, CA
Rep Power: 8
Just an FYI, V8 Vantages after 2010.5 don't need to have misfire corrections relearned after battery failure/jumpstart. That being said, if you replace your clutch/flywheel, misfire corrections cannot be re-taught by simply disconnecting the battery - someone with AMDS needs to perform the relearn procedure.
Just went though this whole debacle after getting the clutch/flywheel on my GT.
Just went though this whole debacle after getting the clutch/flywheel on my GT.
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Joined: Feb 2024
Posts: 121
From: St. Petersburg, FL
Rep Power: 0
probably the rotational inertia will be different. the TSB specifies a bunch of actions where they should be relearned which seem to be either sensors replaced or parts with mass replaced
Registered User
Joined: May 2022
Posts: 101
From: San Diego, CA
Rep Power: 8
Correct.