CEL light after MHD Tune

I installed a catless downpipe and MHD stage 2 tune oct 93. I installed the tune today and it was successful flashing and cleared all my codes. I drove the car normal at first and then I started pulling the car to feel the power differences. I even raced my friend's rs3 and I won lol, but after that car was still fine. When I was driving back home from work 3 hours later not in "Sport Mode" I got a CEL and got worried. Help me diagnose this issue.



Here is the code I pulled from it:


- DME active codes -
118001 - Mixture control: mixture too lean.
21B055 unknown
21B056 unknown

- DME shadow (inactive) codes -
30E1C unknown
10D000 unknown
11CF30 - Mixture control: Multiple fault.
24000B unknown

- Misc. information -
MHD build: version 1.47
Voltage 12.54V
Last flashed file : v1.5 Stage2 93oct_98ron
VIN: WZ1DB4C00LW030276
Factory software:
HWEL 3DDE v003_019_006
HWAP 3DD1 v255_255_255
BTLD 48DC v001_011_001
SWFF 5D55 v060_110_005
TPRG 6354 v060_110_005

Current software:
HWEL 3DDE v003_019_006
HWAP 3DD1 v255_255_255
BTLD 48DC v001_011_001
SWFF 5D55 v060_110_005
TPRG 6354 v060_110_005
CAFD 2742 v000_171_006
Current PRG (hex): 5D553C6E05

ECU status: -

- Readiness -
Misfire: Complete.
Fuel System: Complete.
Components: Complete.
Catalyst: Not avail.
Heated Catalyst: Not avail.
Evaporative System: Complete.
Secondary Air System: Not avail.
A/C Refrigerant: Not avail.
Oxygen Sensor: Complete.
Oxygen Sensor Heater: Complete.
EGR System: Complete.

62 25 02 00 00 00 04

You can lookup the codes (mostly the active ones) here: https://bmwfault.codes/
118001 = Mixture control: Fuel-air mixture too lean

Are you actually fueled up with octane 93?
Here in Belgium, stations advertise with octane 93 but sometimes it is a little bit below the value (as with all tolerances).

Or maybe on an empty tank?


I am always adding octane booster when I fuel up the car, just to be sure. But this is because the tune pushed the car to 'its limits', so it was recommended to use octane booster to make sure I am not getting misfires (knocking sensor kicking in).

But than again, I am not an expert on cars
There will be people here who could 'diagnose' this better

Yea, I use 93 pump octane from shells. I dont know how true they are to 93 octane. I can try adding octane booster too see if that helps. Also, I am on half a tank right now when the CEL came on.

Hmm, "Mixture too lean" just seems to tell me that the O2 sensor is detecting the changes in flow because of the catless downpipe. Does your MHD tune have an option to not detect the CEL for the downpipe?

Ryco said:

I installed a catless downpipe and MHD stage 2 tune oct 93. I installed the tune today and it was successful flashing and cleared all my codes. I drove the car normal at first and then I started pulling the car to feel the power differences. I even raced my friend's rs3 and I won lol, but after that car was still fine. When I was driving back home from work 3 hours later not in "Sport Mode" I got a CEL and got worried. Help me diagnose this issue.



Here is the code I pulled from it:


- DME active codes -
118001 - Mixture control: mixture too lean.
21B055 unknown
21B056 unknown

- DME shadow (inactive) codes -
30E1C unknown
10D000 unknown
11CF30 - Mixture control: Multiple fault.
24000B unknown

- Misc. information -
MHD build: version 1.47
Voltage 12.54V
Last flashed file : v1.5 Stage2 93oct_98ron
VIN: WZ1DB4C00LW030276
Factory software:
HWEL 3DDE v003_019_006
HWAP 3DD1 v255_255_255
BTLD 48DC v001_011_001
SWFF 5D55 v060_110_005
TPRG 6354 v060_110_005

Current software:
HWEL 3DDE v003_019_006
HWAP 3DD1 v255_255_255
BTLD 48DC v001_011_001
SWFF 5D55 v060_110_005
TPRG 6354 v060_110_005
CAFD 2742 v000_171_006
Current PRG (hex): 5D553C6E05

ECU status: -

- Readiness -
Misfire: Complete.
Fuel System: Complete.
Components: Complete.
Catalyst: Not avail.
Heated Catalyst: Not avail.
Evaporative System: Complete.
Secondary Air System: Not avail.
A/C Refrigerant: Not avail.
Oxygen Sensor: Complete.
Oxygen Sensor Heater: Complete.
EGR System: Complete.

62 25 02 00 00 00 04

Click to expand...

take a log and monitor your fuel trims and post the log here. thats a closed loop fuel system code.

Twisted Tuning said:

take a log and monitor your fuel trims and post the log here. thats a closed loop fuel system code.

Click to expand...

Okay, i will do that Thursday and post the logs

cutsman said:

Hmm, "Mixture too lean" just seems to tell me that the O2 sensor is detecting the changes in flow because of the catless downpipe. Does your MHD tune have an option to not detect the CEL for the downpipe?

Click to expand...

That i do not know. I would have to get in contact with MHD about there tunes for this car.

Ryco said:

That i do not know. I would have to get in contact with MHD about there tunes for this car.

Click to expand...

I want to know too. I'm also gonna go with MHD with a catless DP. What catless downpipe are u running?

Twisted Tuning said:

take a log and monitor your fuel trims and post the log here. thats a closed loop fuel system code.

Click to expand...

should i clear the code before running the monitor or run it while the CEL is on?

Ryco said:

I installed a catless downpipe and MHD stage 2 tune oct 93. I installed the tune today and it was successful flashing and cleared all my codes. I drove the car normal at first and then I started pulling the car to feel the power differences. I even raced my friend's rs3 and I won lol, but after that car was still fine. When I was driving back home from work 3 hours later not in "Sport Mode" I got a CEL and got worried. Help me diagnose this issue.



Here is the code I pulled from it:


- DME active codes -
118001 - Mixture control: mixture too lean.
21B055 unknown
21B056 unknown

- DME shadow (inactive) codes -
30E1C unknown
10D000 unknown
11CF30 - Mixture control: Multiple fault.
24000B unknown

- Misc. information -
MHD build: version 1.47
Voltage 12.54V
Last flashed file : v1.5 Stage2 93oct_98ron
VIN: WZ1DB4C00LW030276
Factory software:
HWEL 3DDE v003_019_006
HWAP 3DD1 v255_255_255
BTLD 48DC v001_011_001
SWFF 5D55 v060_110_005
TPRG 6354 v060_110_005

Current software:
HWEL 3DDE v003_019_006
HWAP 3DD1 v255_255_255
BTLD 48DC v001_011_001
SWFF 5D55 v060_110_005
TPRG 6354 v060_110_005
CAFD 2742 v000_171_006
Current PRG (hex): 5D553C6E05

ECU status: -

- Readiness -
Misfire: Complete.
Fuel System: Complete.
Components: Complete.
Catalyst: Not avail.
Heated Catalyst: Not avail.
Evaporative System: Complete.
Secondary Air System: Not avail.
A/C Refrigerant: Not avail.
Oxygen Sensor: Complete.
Oxygen Sensor Heater: Complete.
EGR System: Complete.

62 25 02 00 00 00 04

Click to expand...

This is an old thread, but did you ever resolve this issue?