peugeot 407 Can BUS Fault

chris.mogs · Post by **chris.mogs** » Thu Aug 22, 2019 7:35 am

Hi
Could youa have alook as at this CAN BUS capture and give me youe thoughts.

I'm new to scope testing however this does not look right to me as they dont mirror each other, the voltage is to low and the wave does not match any given example on the Pico guided test. Does anyone have a trace of what it should look like?

I did notice that there is an open on the BSC:

CBB2 Boot lock control: open circuit. The boot opens from the remote without any issues.

I'd like to know where the network resisters are located. I know theres one in the ECU and I guess theres also one in the BSC in the boot. If I unplug the BSC I should see 120ohms confirming the fault location.

I will be testing some more today.

I look forward to your thouhgts and advice.

Reagrds

Chris

Peugeot 407 2.0 SID803

Iver · Post by **Iver** » Fri Aug 23, 2019 8:37 am

As you say that is all wrong. Voltages are wrong, Can H & L are both dormant at 2.5v, you have just a few mVolts there. And they are not mirrored either.

What is wrong with this car? What are the symptoms? If you are just playing/practising with your new scope then the measurement technique may be slightly off track.

Where are you probed to take these measurements ?

I'd like to know where the network resisters are located.

Not all CAN Networks have resistors !! Your Car will have more than One Network !!

I know theres one in the ECU and I guess theres also one in the BSC in the boot. If I unplug the BSC I should see 120ohms confirming the fault location.

Once again, the 120 ohms resistors are not in Every CAN Network. Certain Networks need them and some dont, but that is a 2 day course so we wont delve too deep here.

BSC in the boot

what are you referring to here ? If memory serves me correctly then the BSI is behind the glove box. The BSI controls locks lights etc so what is BSC in the Boot doing. Enlighten me ?

Non Powertrain stuff in PSA vehicles will be on a VAN network not CAN, there are differences between the two.

CBB2 Boot lock control: open circuit. The boot opens from the remote without any issues

That fault code is not telling you it cannot open from the Remote.

It is clearly telling you there is a fault with the LOCK, not OPENING or CLOSING.

chris.mogs · Post by **chris.mogs** » Fri Aug 23, 2019 9:55 pm

Thanks for the reply.
Initially I wanted to do a health check on the CAN. I'm contected at the DLC via a breckout box. I was looking for 60omhs on my meter between Can H and Can L but all I have is an open thats what lead me onto my scope test.
There are two resistors one in the ECU and one in the ABS module. I ran a quick scan and there are faults on the ABS module that require further investigation.

Your are spot on about the BSI the BSC is the boot fuse box which at the time I thought would house one of the reisistors.

I have yet to look at the boot lock but they are known to breck the wires in the loom between the boot lid and where it goes into the chasis.
The current fault is a crank non start:https://www.picoauto.com/support/topic21889.html

A two day course in Can resistors Ive been considering taking some training as I found this subject very interesting.

Many thanks for your advice

Regards

Chris

Iver · Post by **Iver** » Sun Aug 25, 2019 12:33 pm

[quote]I'm contected at the DLC via a breckout box. I was looking for 60omhs on my meter between Can H and Can L but all I have is an open thats what lead me onto my scope test.[/quote]

You will not always see Powertrain or Convenience CAN network at the DLC. It looks as though the BSI is the Network Gateway in this car. For those reasons you are looking in the wrong place for 60 ohms and Can Waveform.

There are two resistors one in the ECU and one in the ABS module. I ran a quick scan and there are faults on the ABS module that require further investigation.

What are those faults ??

The current fault is a crank non start:https://www.picoauto.com/support/topic21889.html

Why dont you fix that first ???

Mr. Wizard · Post by **Mr. Wizard** » Sun Aug 25, 2019 3:31 pm

Chris,
Try recording the CANBus again and make sure you ground both channels of the scope. May I suggest the following scope setting
5ms/div
2G sample per second (Max it Out)
Channel (A) CAN Hi 5volts DC coupled
Channel (B) CAN Lo 5volts DC coupled

What you recorded before looks like random noise.

chris.mogs · Post by **chris.mogs** » Sun Aug 25, 2019 7:40 pm

Many thanks for your reply I do appreciate the feedback. Getting the engine to start is my main priority.

Regards

Chris

Iver · Post by **Iver** » Mon Aug 26, 2019 12:20 am

Mr. Wizard wrote: ↑
Sun Aug 25, 2019 3:31 pm
Chris,
Try recording the CANBus again and make sure you ground both channels of the scope. May I suggest the following scope setting
5ms/div
2G sample per second (Max it Out)
Channel (A) CAN Hi 5volts DC coupled
Channel (B) CAN Lo 5volts DC coupled

What you recorded before looks like random noise.

Mr Wizard.

You are no wiser than he is.

He is measuring in the wrong place with the wrong prerequisites !!! Scope settings are not the issue here.

This car is a Crank but No Start with Fuel Pressure Faults. It makes no sense to be looking at CAN just now based on the info supplied

chris.mogs · Post by **chris.mogs** » Tue Sep 03, 2019 5:09 pm

Many thanks for the feedback. My reason for checking the CAN was due to U2001 remotely controlled engine wake up and U1118 no comms with the BSI interface. Having checked the ECU/BSI parameters neither are valid. The BSI is working and the ECU is unlocked and authorised for engine start.

The focus is the non start fuel issue

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