206cc 2.0 litre, faulty ECU?

V

VRaptor

Member
VIP Paid Subscriber
Tadpole
Tadpole
Joined
Jan 10, 2024
Messages
35
Location
BALLARAT, Victoria
Long story short. Was getting a P0106, then a P0108 code. Replaced MAP sensor, but fault remains.
Using my scan tool, checked live data from EOBCD, everything looked fairly normal.
However, I recently discovered I could also check live data using the diagnostic mode. (Launch cr919x)
This test concerned me as I was now seeing erratic data on multiple levels, battery voltage from 0 to over 25v, similar on air and coolant temperature, and also manifold vacuum. It was peaking at nearly 4000kpa! No wonder it was throwing a P0108 code!
At first I was suspecting an intermittent wiring short, but after seeing the scan tool data, I'm thinking I have an ECU issue.
I'll post a shot of my scan tool screen. This was recorded with KOEO mode, so static.
Looks like the program won't let me post a pic, file too large?
Anyway, maybe a related issue, also getting a large rpm on startup with engine surging. Only sometimes but quite disconcerting.
So wondering if other members have seen similar issues and what was the fix?
Cheers!
 
Have you confirmed any of the data ie battery voltage. Is the launch being used in manufactures data or obd. And is the throttle body cable or electric. Have you checked for manifold leaks or a broken stop on the TB plenty of questions need more information
 
Most of the time when people suspect they have a faulty ECU the fault is something going into the ECU rather than the ECU itself. The odd results your are experiencing cause me to wonder about your scan tool. It's hard to know what to suggest from what you have as yet.

If your image file is too large, you might need to export it to a smaller size before you upload.

Cheers

Kim
 
Thanks for the replies. I have been getting to diagnose further, and getting more confused! I have deep diving further into the available data I can glean from my scan tool.
So, just to simplify things a bit, if I look at the battery voltage through data stream, I can see a steady 12.6v in the air intake module. However, if I check battery voltage in the engine cooling system, the battery voltage shows a constantly changing voltage from 0 to about 25v! Obviously this is incorrect data, as the battery voltage is a constant. So, some modules will give me stable, correct data, and others are giving me wildly changing data. These swings appear to be rythmic. I'm beginning to suspect maybe a bad ECU ground, but that is just a guess.
Interestingly, I can get some stable data when I select only a couple of items to view, but then just add one more, and I get all the data fluctuating!
This is becoming a bit frustrating, as it's becoming hard to diagnose where the issue is coming from, and then getting DTC codes, included the dreaded anti pollution fault.
Another interesting thing, is in the data stream I am getting incorrect coolant temperature (159C) and engine oil temp readings (-40C), but they read correct on the dash?
 
VRaptor said:
Another interesting thing, is in the data stream I am getting incorrect coolant temperature (159C) and engine oil temp readings (-40C), but they read correct on the dash?
Click to expand...
I'm no expert on Peugeots, but on the modern cars that I have been involved with there is separate sensors for the temp gauge and the ECU. Those temps are definitely not correct, before you blame the ECU check the sensors and also the connections as this could be where your problem lies.

With the supply voltages that seem to be abnormal, get yourself a multimeter and read those voltages directly at those points to confirm that the scan tool is giving correct information.

Also answer the questions that Dave has ask you in post #2, he has lots of experience with these cars.
 
Throttle body is motor controlled, no cable, and in good condition. Used the scan tool in both obd and data stream mode. Voltages have been confirmed using multimeter, and looked for voltage drops at various earth points. Looked ok. The MAP sensor has been replaced and the same errors remain, indicating the problem is elsewhere. Coolant temp sensor is maybe suspect, but that was from the scanner data. Replacement ordered.
Don't think I should be throwing parts at it with fingers crossed!
 
Your diag tool is incorrectly decoding the data stream, for example it could be using template for a different spec engine or a 2005 model instead of 2001.
You can try selecting different engine types and see if there's one that has more sensible readings.
 
Alex, there is no option to select a different engine. The scanner is utilising the VIN to determine the correct profile. It is selecting the ECU correctly as a 6lp. If I could post my scanner pics, it may be more clearer.
 
dmccurtayne said:
Have you confirmed any of the data ie battery voltage. Is the launch being used in manufactures data or obd. And is the throttle body cable or electric. Have you checked for manifold leaks or a broken stop on the TB plenty of questions need more information
Click to expand...
I'm curious if you know the difference by using OBD2 data, or the manufacturers data? The two don't seem to directly correspond. So I'm suspecting that the two days streams are different for some reason?
 
For what it's worth, one of my manuals says regarding the codes:

P0106 is either that the pressure drop at start was to small, or that the inlet pressure is high for the butterfly position.

P0108 is likely a short to earth on the intake air pressure sensor.
 
Thanks Seasink. I'm no longer being the P0106 code. From what I understand the P0108 is high voltage. That makes sense if the ECU voltage spikes I'm seeing in live data are true. I'm suspecting a wiring issue somewhere, just need to find it! I am getting some strange readings that don't make sense to me at present. For instance, engine oil temperature in live data is showing -40C. Obviously not correct, but gauge on dash appears to be correct. The MAP has been replaced, so that is not the issue, but I am suspecting maybe a faulty ground somewhere, or possibly one of my other sensors is faulty, but is not throwing a code. I do have an ECT sensor on the way, as I have been getting some engine coolant temperature error codes. Will see what happens when that one is replaced.
I was going to take the car to a local European car technician for some expert diagnosis, but currently looking at a five week wait!
I'll be a much happier person when I eventually get to the bottom of this little technical hitch!
 
VRaptor said:
I'm curious if you know the difference by using OBD2 data, or the manufacturers data? The two don't seem to directly correspond. So I'm suspecting that the two days streams are different for some reason?
Click to expand...
Yes the man data is often filtered and obd data is raw
 
A quick update. Started to dive deeper with my multimeter. Found two issues. The coolant sensor is indeed faulty. I removed it and tested it and found the resistance was erratic, and when I put into some hot water, it went open circuit! That will explain the error and it maybe influencing the MAP sensor code as well. Still waiting for a new sensor to arrive.
I also checked the oil temperature sensor, and couldn't get a 5v reference voltage. I haven't managed to find where the break is yet. I also couldn't find a wiring diagram that includes the oil temp sensor, so dont know where it pins out of the ECU.
In case the sensor does prove to be faulty, I also couldn't find a replacement either!
Well, I'll try and get these two issues sorted, and see what else pops up!
 
I eventually located a wiring diagram by searching for the oil level sensor. And then found the alternative sensor that includes the temperature sensor. So the knowledge is slowly growing. According to the wiring diagram, this sensor does not go to the ECU, but direct to the instrument cluster. I haven't diagnosed further yet, but now getting to see where I need to go!
 
  • Like
Reactions: COL
You must log in or register to reply here.
Top