# DBW randomly fails **URL:** \ **Category:** V3 SOFTWARE\ **Created:** [September 26, 2024, 7:28pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389 "2024-09-26T19:28:50Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [September 26, 2024, 7:28pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/1 "2024-09-26T19:28:50Z")
Hi for some months now i have a strange issue, which i think is SW related. I drive normally and suddenly the throttle is dead. DBW out DC is raising to 100% but throttle is not moveing: ![image](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/4/46f8123a4f3d7d3cfa4116fe52b15b2b3124b37f.png) [AudiTT\_AJQ\_rev77.emub3](https://community.ecumaster.com/uploads/short-url/6fLUbnW0aFkT7LowbX0opAoSP5G.emub3) (64.5 KB) [20240925\_1757\_rev77\_fahrenCCDBWProblem.emublog3](https://community.ecumaster.com/uploads/short-url/ySFyfkDAQWPHkfn1cBeTZyhbSoF.emublog3) (2.7 MB) TPS and PPS sensor seem to be completely fine. It seems like no current is reaching the throttle motor. Usually i would say HW issue (wiring or throttle itselfe) but after an ignition cycle it immediately works again. It happens around once a week. Can this probably something strange in the SW? In addition one wish…in V2 if u do an ignition cycle during driving…engine was immediately working again. Now with V3 the pedal is dead until u drop below a certain rpm. Would be better if it is behaving like V2 in case u need a fast reset due to issues like this Throttle problem. ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [September 26, 2024, 9:14pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/2 "2024-09-26T21:14:06Z")
According throttle issue, please just make sure all power grounds are connected to EMU. I will add some more debug information to log, to try to determine the state of the 2nd microcontroller that controls the DBW PWM. It is really hard to say right now what could be a problem, but it seems to be serious. Could you provide me a log when the throttle doesn’t work properly after ingintion cycle when the engine is running ? It shouldn’t be like that. ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [September 26, 2024, 9:28pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/3 "2024-09-26T21:28:55Z")
I first also was thinking about a ground problem. Therefor i upgraded my ground wires (there was potential to improve). But it didn’t change anything. But i will check again. I don’t have logs of that at the moment. Will provide one the next days. ---
**Author:** ![Greg](https://avatars.discourse-cdn.com/v4/letter/g/71c47a/32.png) [@Greg](https://community.ecumaster.com/u/Greg)\ **Post date:** [September 27, 2024, 9:52am UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/4 "2024-09-27T09:52:29Z")
I had similar problem but was related to the rpm- above certain rpm dbw just dropped as your with full duty cycle . that was aftermarket motor for ITB made By at throttles . after installing av mounts all gone … but with “normal” throttle Im not sure if that a case… ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [September 27, 2024, 10:04am UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/5 "2024-09-27T10:04:58Z")
Interresting…was ur issue reproducable or sporadic? On a different engine i expirienced something similar…over a specific rpm dbw went 100% dc and couldnt reach the target. This was reproducable and the issue was gone after a ground problem was fixed. But my current case is sporadic and if it is a ground problem i dont understand why a KL15 reset heals it. ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [September 27, 2024, 10:54am UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/6 "2024-09-27T10:54:53Z")
I added some diagnostic channels for next build. We will know more then. ---
**Author:** ![Greg](https://avatars.discourse-cdn.com/v4/letter/g/71c47a/32.png) [@Greg](https://community.ecumaster.com/u/Greg)\ **Post date:** [September 27, 2024, 11:34am UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/7 "2024-09-27T11:34:06Z")
Well my case was a strange one … car did couple of races without issue and than started making that … ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [September 27, 2024, 12:00pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/8 "2024-09-27T12:00:11Z")
Here a log from ignition swap during driving: ![image](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/1/19417312b403da7910d1c72445d7b129ae457d16.png) [20240927\_1333\_rev77\_warmup+Ignitionswapdriving.emublog3](https://community.ecumaster.com/uploads/short-url/2jTeS4rEdJC4UjFOgtjavkbJQw1.emublog3) (689.0 KB) Actually DBW is working there, but there is no injection and ECU state says inactive. After droping below 1500-1800 rpm then everything always is working again. ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [September 27, 2024, 1:20pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/9 "2024-09-27T13:20:39Z")
The reason is cruise control, so it is inactive until you have pressed the clutch pedal. It will be improved in the next fv varsion. ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [September 27, 2024, 3:34pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/10 "2024-09-27T15:34:18Z")
Sounds highly confusing for me without knowing the code…but good if u can fix it 😃 ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [September 27, 2024, 7:14pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/11 "2024-09-27T19:14:02Z")
if you enable cruise control you need to press clutch or brake pedal to start the engine 🙂 So when you restart ecu the state machine waits for it. You pressed the clutch to prevent engine to stall and the engine starts again 🙂 ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [September 27, 2024, 7:18pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/12 "2024-09-27T19:18:41Z")
Ah…makes sense…i forgot this cause it anoyed me. I set a function as brakeswitch…that brakeswitch is active below a specific rpm and i can start engine without pressing. If u ask me u can remove this need or at least set it optional😂 ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [September 27, 2024, 8:51pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/13 "2024-09-27T20:51:16Z")
It is safety protection to make sure at least clutch or brake pedal are connected. However your issue with restart engine is quite simple to fix. When there are RPM over cranking threshold, the brake / clutch switch condition will be ignored. ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [September 27, 2024, 9:06pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/14 "2024-09-27T21:06:49Z")
Okay with this intention the check is senseful. ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [October 7, 2024, 3:36pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/15 "2024-10-07T15:36:37Z")
I’ve add two new channels that log the activity of DBW hardware. If you will be able to reproduce the issue with new firmware it will give us valuable information (I hope). Also when you turn off and on the ignition it will restart engine immediately ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [October 7, 2024, 4:48pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/16 "2024-10-07T16:48:42Z")
Thx a lot. But will take some time to catch the event with a log. ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [October 9, 2024, 5:16pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/17 "2024-10-09T17:16:24Z")
Just installed the SW and 5 mins later i had an event…lucky day. ![image](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/b/b7acc8a6ef43f6048b7c3be7932199b687b8114c.png) [20241009\_1842\_rev80\_drivingwithDBWfail.emublog3](https://community.ecumaster.com/uploads/short-url/lxMs8h0mVQe2DNi4kIh0K135JYd.emublog3) (635.3 KB) DBW HW state jumps to “no error” from “DBW mode”…what does this mean? Btw…Ignition reset during driving is working now…thx for that 🥳 ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [October 9, 2024, 7:28pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/18 "2024-10-09T19:28:24Z")
It is something serious. It looks like 2nd microcontroler resets. I need to be able to reproduce it on the bench. ---
**Author:** ![Jadzwin\_ECUMASTER](https://dub1.discourse-cdn.com/flex013/user_avatar/community.ecumaster.com/jadzwin_ecumaster/32/28_2.png) [@Jadzwin\_ECUMASTER](https://community.ecumaster.com/u/Jadzwin_ECUMASTER)\ **Post date:** [October 10, 2024, 2:05pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/19 "2024-10-10T14:05:40Z")
When you lost your DBW control, did the CAN bus work (eg. dashboard) ? ---
**Author:** ![derUltraTT](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@derUltraTT](https://community.ecumaster.com/u/derUltraTT)\ **Post date:** [October 10, 2024, 4:07pm UTC](https://community.ecumaster.com/t/dbw-randomly-fails/2389/20 "2024-10-10T16:07:17Z")
I have a ADU with a lot of CAN input…i can’t remeber to see anything there which indicatded a CAN brakedown. In addition i have some CAN inputs on the EMU…e.g. Vehicle speed and CAN Analog1 + some switches. In the logfile all those values are plausible during and after the event. So i assume the CAN was in a working state. One note to that topic…i am useing CAN DBW for some stuff and i send the associated msg permanently, but with value 0 when i don’t want CAN control. [Next page](https://community.ecumaster.com/t/dbw-randomly-fails/2389.md?page=2)