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Discussion Starter #1
So I'm still trying to track down an ESP fault U1208 but almost everything in Diagbox seems to be working/reading fine. speed sensors, yaw etc. The only things that aren't reading correctly are the torque values. 'Actual torque' and 'torque required by driver'. Both are always stuck at a constant 408nm. I'm not sure if this is the way it's supposed to be or not since I have no other reference.

Previous owner has the egr blocked off too, and maybe turned off in the engine ecu (not sure) but some of the egr readings in diagbox always read with a negative value, usually zero -0%. A few read 1%

Is it possible that the torque is calculated using some egr values and the negative values are forcing it to a default value, and hence affecting the torque reading that the ESP system is looking for?

The egr has a 5v ref, good ground, 0v signal, and a slightly negative reading from the 12v power wire, at the egr and at the ecu. Strange that it's reading negative (-0.01v) from a 12v power, could the previous owner have messed up when editing the egr out of the engine ecu? would the ecu compensate for a negative value?
Tried unplugging the egr but it makes absolutely no difference.

I really need to get rid of the stupid ESP warning light for the NCT, and disabling the ESP in diagbox doesn't seem to make any difference! Light just pops on at engine start and never goes away.. The reason for failing the NCT was "Some warning light on the dash, traction control or something" lol..


 

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Torque required by driver is derived from the accelerator pedal position and actual torque is what is current from motor [derived from rpm, timing, fuel supply to injectors etc etc]. They should constantly vary.
Not sure what effect removing the EGR from the ECU would have on the whole thing, but it should only really affect what is available, not what is required by the driver, as driver's input is theoretical, like a wish list...
Maybe whoever removed the EGR from the ECU programming somehow trashed this part of the programming?
Have a look at the connectors to the ECU. It was obviously removed to do the reprogramming so maybe pins/connectors were damaged at some point replacing it? Also check for corrosion of the pins/connectors.
 

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Discussion Starter #5
Torque required by driver is derived from the accelerator pedal position and actual torque is what is current from motor [derived from rpm, timing, fuel supply to injectors etc etc]. They should constantly vary.
Not sure what effect removing the EGR from the ECU would have on the whole thing, but it should only really affect what is available, not what is required by the driver, as driver's input is theoretical, like a wish list...
Maybe whoever removed the EGR from the ECU programming somehow trashed this part of the programming?
Have a look at the connectors to the ECU. It was obviously removed to do the reprogramming so maybe pins/connectors were damaged at some point replacing it? Also check for corrosion of the pins/connectors.
Nice one, that makes sense alright. Yea the accelerator percentage is fine so I assume that means 'torque required' should work fine. Also I'm thinking the egr value is probably added into an equation, and not really a multiplication so it probably shouldn't affect the whole thing, if that makes sense.

Is it possible to do an engine ecu reset? I saw an option in Diagbox but it said it's only used when installing a new ecu. Might be a dealer job to flash the software maybe?
 

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I have seen that option but have not ventured down that path.

If you want to try it, you would need to do a total dump of your current ECU before doing it so you could restore your ECU to current state before you did the reset.

I have a BDM100 unit and have made a copy of all my ECU's just in case anything goes wrong.

Maybe you could get a standard ECU dump from someone and overwrite your ECU? But make a copy of yours first of course.
 

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Discussion Starter #8
I have seen that option but have not ventured down that path.

If you want to try it, you would need to do a total dump of your current ECU before doing it so you could restore your ECU to current state before you did the reset.

I have a BDM100 unit and have made a copy of all my ECU's just in case anything goes wrong.

Maybe you could get a standard ECU dump from someone and overwrite your ECU? But make a copy of yours first of course.
Hmm.. might be the way to go alright. Just having a look there and the BDM100's seem to be fairly reasonably priced. And it'd be a new toy for me to play with too.. :) It's a balls buying a car with faults since you never know what the previous owner has been messing with!
 

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Discussion Starter #9
Engine torque is not really anything to do with ESP the U code is a network type fault

Have you checked the steering angle sensor calibration
Steering calibration is good. It was out by ~60 and Diagbox wouldn't calibrate it properly, some type of bug in the software I'm thinking, but I managed to get it done with PP2000.

I think I read somewhere that the ESP uses the torque value alright, to know if you're accelerating, and when to cut power to certain wheels etc..

Yea, the code is "no communication with engine ecu" but the CAN network is fine. The reason that the code gives is 'data invalid', which is what led me to the reasoning above. All the other variables seem perfect, ABS is fine, cruise control is fine, yaw, transverse acceleration too etc..
As far as I know torque is the only variable that the esp ecu is looking for from the engine ecu, and the only thing that's not working right...
 

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A lot of the signals shared between systems go through the underbonnet fusebox check all the connectors are good

Data invalid could mean anything from too high to to low to nothing at all and all it takes is a high resistance contact somewhere to upset a signal
 

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Is ESP enabled in engine ECU and do you know if car has been remapped.

Torque is looked up in torque control map. Some poor remappers have been known to modify the torque/mg3 offsets when they miss some limiters to get increased fuel rates which then screw the data values when the ecu looks at calculated valves vs estimate from crank sensor
 

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Discussion Starter #12
A lot of the signals shared between systems go through the underbonnet fusebox check all the connectors are good

Data invalid could mean anything from too high to to low to nothing at all and all it takes is a high resistance contact somewhere to upset a signal
Yea, I've pulled almost everything apart at some stage, checked fuses, connections etc. With the exception of pulling the whole harness out. I've been looking up/researching the CAN system too and I'd say it's fine. The fact that the abs and cruise control systems are working fine seems to narrow it down quite a bit too.

Is ESP enabled in engine ECU and do you know if car has been remapped.

Torque is looked up in torque control map. Some poor remappers have been known to modify the torque/mg3 offsets when they miss some limiters to get increased fuel rates which then screw the data values when the ecu looks at calculated valves vs estimate from crank sensor
Yea, esp ecu is enabled. I've tried disabling and reenabling it to try to get the light to disappear just for the nct but no go!
Not sure if it's been remapped but I wouldn't be surprised since the egr has been blocked, and I think the DPF has been removed too, and there were some gadgets in the car, an ELM327 and a few PCB's that looked like they were soldered on to the ELM at some stage, if that makes sense? Previous owner was definitely messing with some stuff!
Do you think a dealer could reset/update/reboot the ECU? Or would it be a remapping specialist job?
 

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Discussion Starter #13
Spent a few hours today ripping out the harness, shortcutting the CAN wires from the eng ecu to the abs ecu and generally screwing around. Everything looked fine, wires under the harness cover looked like new, no water, no breaks, etc..
Then while browsing online I finally found a proper/accurate original bin file for my engine ecu, so I flashed it there while ago. Bit scary as it was my first write to the ecu.. :eek:

It confirmed my suspicions (above) about it being an incorrect torque value/egr issue as I now get the proper errors. U1208, P1728, P0405. Previous owner must have deleted a bunch of error paths to get rid of the EGR.



ENG ECU:
Engine torque sent on CAN is incorrect: P1728
Low egr raw repeat signal: P0405

ESP ECU:
The U1208 is just the 'esp side' of the P1728 fault (invalid data from eng ecu)


Anyone come across these three errors together? Think I'll pull the egr apart tomorrow and see what's happening with it, I might be able to get more accurate readings now that it's active again in the engine ecu. The negative value for torque also seems to suggest that it's related to the EGR negative values as I mentioned above, in fact I would have been surprised if it had read a positive value....





 

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Discussion Starter #14
Just an update to finish this off:
Finally sorted the problem. I took off the EGR, removed the blanking plate the previous owner had put in, and gave the EGR a good clean with a mixture of brake cleaning fluid and WD40 and a good scrub with a screwdriver and a cloth. until it was opening freely.

As soon as I put it back together the ESP light was gone and both torque values were reading perfectly again. I still had an engine light on and a a new anti pollutant error, both of which went away after clearing the errors in Diagbox a few times and a few engine restarts.

I already had the egr and dpf mapped out so I don't even know if the EGR is working properly (it's still showing a few 'data invalid' values in Diagbox maybe due to being mapped out) but as soon as I pass the nct later this week I'll probably put the blanking plate back in, until then I'm not going to touch it!

Nice one for the replies
 
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