PicoScope 7 Automotive
Available for Windows, Mac, and Linux, the next evolution of our diagnostic scope software is now available.
STC wrote:
I have WDS, ICOM, and an Account with BMW Tech Info. Just shout if you need any thing.
It runs and drives - it wont be doing that with 1v at the ECU power supply fuses.I have just learned today after litace post to check the fuses and power supplies that unless the engine is actually running there is no battery voltage to the fuses,
Now you want to teach me the strategy of that controller when you have doubts yourself - that will not end well ?which supply the power supplies for the ECM, actually ignition on the voltage at the fuses were 1.31V.
Bin that procedure, or learn to interpret it correctly.The AD checking procedure says B17 signal from ECM to the lambda's and yes the injectors but I was not looking at those, should be battery voltage with the ignition on, however according to the wiring diagram there is an ignition control relay grounded by the ECM, but at what point, is that at ignition on or engine cranking, I don't know I was not looking for that either. If then the AD checking procedure is incorrect then the B17, B29 at ignition on will not be battery voltage if the K46 control relay has not activated, via the ECM. It appears at the moment then that B17 and B29 will only output battery voltage with the engine running, and if that is the case when I now double check it, and it more than likely will be, the AD checking procedure is incorrect.
Loosely speaking that is the case but you are measuring the right thing in the wrong way at the wrong time with the tool set up wrong and have not grasped what you need to be looking for. I'm not about to give it away with little chance of a return in the future. We have been down that road before.The ECM B18 terminal is a switched earth, the battery feed originates from B17 and B29, through the heaters of the oxygen sensors back to the ECM terminal B18.
Yes I do - and I disagree with lots of Guided tests from the VM's. Some are nowhere near conclusive enough and do lead to a misdiagnosis.AD advise that a scope setting of 5V/0.5 sec is recommended to check the PWM signal, but you disagree STC!!
You seem hell bent on looking for a PWM that is not there. There are many variables as to why not. ECU failure is one which you have picked up on, there are others that the statistics will favour.The battery voltage (running engine) will be around 14.7V, AD advise 5V per division on the scope to display the PWM signal, which read nothing until I dropped the voltage to 0.2V. All this must have something to do with ignition on and engine running then, hence I''ll double check all measurements tomorrow.
Emulate the heater circuitTechnician wrote:STC,
Given that you disagree with everything said, and you disagree with AD's test procedures as well, there is no pleasing you, so I have a solution.
You tell me how the circuits based on the two fault codes should be tested, the only code returned is the lambda code after road test.
Dcunning35 wrote:Morning tech ,
Could you look at the ,map,iat,tp upstream 02 serially from cold start through warm up im still trying to understand the rough running in conjunction with the post cat o2 dtc .
Please humour me as I am not with the vehicle but would if possible like to assist.
Does this only occur from initial start, or worsen with engine warm up
Not at the moment I cleared the fault codes then realised I should not have done sorry.Dcunning35 wrote:Open or closed loop? , have you got the freeze frame behind the dtc ? That would really help to know the ecm read engine conditions at time of logging dtc.
The rough running was caused by the lady driver running the engine with no oil in, well actually roughly 1 litre in. The engine must have been nipping up on the pistons and rings etc as the engine was being run too hot. I changed the oil and filter the engine ran then at normal temperature and a good road test proved the engine was running well, however the engine is burning oil quite badly, and given its only done 40 ish thousand miles it's not a lot. A lambda sensor fail after the CAT I'm sure would not cause serious amounts of exhaust smoke (blue).Dcunning35 wrote:Morning tech ,
Could you look at the ,map,iat,tp upstream 02 serially from cold start through warm up im still trying to understand the rough running in conjunction with the post cat o2 dtc .
Please humour me as I am not with the vehicle but would if possible like to assist.
Does this only occur from initial start, or worsen with engine warm up
Yes and No, Many variables, If you have a good car then NO they have not got it wrong. If you have a shorted / open circuit then the controller will need to know and will test for that.Has AD got this wrong, they say that the scope should be set at 5V 0.5 sec and provide an example waveform,
This is a recurring theme with you. In all the years I have read your posts I have yet to see one positive conclusion, one car fixed !She has taken the car today I am to understand that .... .... ......... .............. .................