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Hello guys,

Wondering if anybody can land me a hand with my problem. I have a 2021 MK4 Focus 1.0 EcoBoost mHev. I bought the car last year and start stop has never worked. I did all the basic checks...but i can`t find the problem related to the issue i have.

On forscan, i dont have any error but when i search for inhibitors i find SS_INHIB_G2_27 YES .... after many tries and checks i finally found something that i thinked caused the issue, and that something was EFPS (evacuate and fill process status) from the ABS module with - "production line" status. After i saw that...i went to a ford dealer and requested brake fluid to be changed and ABS bleed procedure....they did that but now EFPS status changed from "production line" to "service fill". I don t think they did the procedure in FDRS complete (from what i know, you must click ok before moving from wheel to wheel, and they did not do that, i ve watched on camera). Main idea is that start stop is still not working, and i wanted to ask you guys if any of you encountered something similar, or if you have expertise on this situations. Or at least, if somebody with the same model can tell me what status the EFPS is showing...that would also be helpful. I`m not sure if there is a status like "complete" / "normal" or something like that.

Best regards!

Edited March 20Mar 20 by alexrol

up

Did you already check the battery condition?

If not, that will be the first thing to do together with changing the targeted State of Charge to 95% instead of 80%. If the battery condition is less than approximately 75% of the original value the stop/start system will no longer work. The vehicle however will still start perfectly fine.

On these cars (and especially the MHEV) the battery deteriorates quite fast. Having to replace the battery every 2 to 3 Years is quite common.


I have worked on quite a few different Ford models and never heard or seen the Start/Stop system being affected by the bleed status of the ABS pump.

I wish mine didn't

3 hours ago, JW1982 said:

If the battery condition is less than approximately 75% of the original value the stop/start system will no longer work. The vehicle however will still start perfectly fine.

I fully concur with this comment. We used to have a Mk3.5 Ecoboost. When bought at around 3 years old the stop-start worked sporadically and over the next few years gradually stopped working. The car still started fine until one day it refused to crank. I charged the battery overnight but despite the charger reporting a full charge with a multimeter showing good voltage it still refused to crank. After fitting a new fully charged battery (and resetting the BMS) the cranking problem was resolved and also stop-start began to work again. Then, over a further few years it started to get sporadic but, again, with the car still starting perfectly well.

I concluded from this that the stop-start (and cranking) maybe doesn't only depend upon the state-of-charge but also the battery capacity, which declines over time and number of charge/discharge cycles.

I checked the battery capacity and it s at 94%, also, i modified state of charge target from 80% to 90% and it constantly stays between 80% - 85%. Also tried my battery on a Fiesta with the same engine but not mHev, start stop worked on Fiest. BMS was reset of course.

Update on EFPS: it does not seem to have nothing to do with start stop. I`ve checked another focus from same generation but diesel, and EFPS shown production line fill (having less miles that vehicle never had brake fluid change) so my conclusion is that factory status is normal to be "production line fill" and after the first brake fluid change with bleed procedure it turns into service fill

I can`t understand though from where SS_INHIB_G2_27 - YES - (start stop inhibited by plausibility monitor) comes, and what to check anymore. Any ideas?

1 hour ago, alexrol said:

I can`t understand though from where SS_INHIB_G2_27 - YES - (start stop inhibited by plausibility monitor) comes, and what to check anymore. Any ideas?

I wonder if the hybrid battery is weak on your car? Stop start is managed by the hybrid system on the MHEV.

Do you have the digital dash to watch the level of charge and boost from the hybrid system while driving?

I have the normal dash/cluster, i can see the icons when hybrid is charging or boosting and the level but not in percents. It reaches full charge and boost, i can check with forscan something specific of the hybrid system if you can tell me what to look for.

21 minutes ago, alexrol said:

I have the normal dash/cluster, i can see the icons when hybrid is charging or boosting and the level but not in percents. It reaches full charge and boost, i can check with forscan something specific of the hybrid system if you can tell me what to look for.

I don't know what to look for on Forscan either unfortunately. If there is a PID for 48v battery state or charge that might be useful to use.

If the boost did not last long between recharges then that would have been a suggestion that the hybrid battery is weak. But not an ideal test.