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      04-18-2024, 11:16 AM   #14
B21
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Drives: E89 Atacama Yellow 35is
Join Date: May 2022
Location: Scotland..God’s own country

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Quote:
Originally Posted by Tangent View Post
The xHP isn't a problem at all; they don't care what you do with the trans tune and don't even check.

For the MHD, simply flash back to stock (not stage 0, the full long-write back to stock. I used the built-in one, not a backed up one) and go for a few drives. I didn't go nearly as far as 200 miles. I did double check that the monitors had completed though. I passed the test this last September.

Here's the drive cycle guide that I use to get the monitors completed in a minimal amount of time. It's not mandatory but it speeds things up.

1. Cold Start
In order to be classified as a cold start the engine coolant temperature must be below 50ºC (122ºF) and within 6ºC (11ºF) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.

2. Idle
The engine must be run for two and a half minutes with the air conditioner on maximum and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.

3. Accelerate
Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.

4. Hold Steady Speed
Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.

5. Decelerate
Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.

6. Accelerate
Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.

7. Hold Steady Speed
Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.

8. Decelerate
This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.
Holy Moly..and people thought the UK MOT test was hard work...!
__________________
Much modified 2011 Atacama Yellow 35is…previously a much modified 2012 Atacama Yellow 20i MSport
Change history here… https://www.dropbox.com/s/8h1vabklgz...0List.pdf?dl=0
Build thread here… https://z4-forum.com/forum/viewtopic.php?t=131886
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