Car dies, all DTCs at once

[M104]

Hi everyone,

My wife's 2006 Peugeot 407 is not doing well at all. Last week the car died after a minute or two idling after a cold start. Trouble codes were EGR and coils: P0406, P0351 and P0352. Suspected an issue with the wiring harness, both EGR and coil plugs being close to each other. Decided to give the harness a look and clean both plugs with contact cleaner and clear the codes.

At that point i decided to drive the car the next day and it ran great for about 50km until the CEL came on with a massive loss of power and felt like it was running on 3 cyl. Parked it and i can't remember but i think it had more codes this time. Ran fine after restarting and drove back home.

Yesterday i've decided to dig into it and took the car for a drive around the block and it just died on me while driving. Every possible engine trouble codes on: all coils, all injectors, EGR, o2 sensor pre and post cat and some others. At this point i couldn't start the car, decided to wait and wiggle a few fuses and i was able to start again about 30 min later. Not sure if the waiting of the fuse wiggling did the trick.

Thought it wouldn't be a bad idea to check and clean every ground connection as well as every plug around the ECM but the car behaved the same today. It idled fine for 30 min then the second time i started it, it died after a minute, this time with codes P1621, P0351 and P0352. Was able to start it for a 3rd time and it died almost immediatly with every possible engine codes again and impossible to start again.

Something important to mention is the P1621 code, there's no way to clear this one. I'm leaning towards a bad ECM at this point. What do you think?

EDIT: In my case,P1621 is: Control Module Long Term Memory Performance/Immobilizer Code Words Do Not Match.

 

[rijndael]

Don't guess at a PCM.

I would pick one of the systems that has issues/codes and run that code down. Hopefully you find something in common, like a bad 5v reference.

I'd pick the EGR system or the no-crank.

 

[SC Maintenance]

I would focus on the P0406. If your combustion chamber is still full of exhaust gases the plugs will require much less voltage to fire - oxygen is a better insulator - so that could account for the P0351 and P0352 - PCM is seeing a much lower voltage than expected.

Just a hunch - but I would rule the EGR out first.

Also, pull those codes from your cars manual if you can - the generic definitions on the internet aren't always complete or the OEM definition might give some additional clues.

 

[M104]

EGR was my first suspect and i tried to start the car with it unplugged when it stalled and was impossible to start but it made no difference at all.

 

[MCompact]

Low battery voltage?

 

[IndyIan]

Low battery voltage?

Something to check anyways, my experience with driving the old tech cars like my 07 Focus, that it runs quite well down to 10V. At 9.XX I think a relay would cut out and turn off the engine for a second or two until the battery voltage creeped back up and it would all come back on.... And it would go a couple km like that even!

 

[SC Maintenance]

EGR was my first suspect and i tried to start the car with it unplugged when it stalled and was impossible to start but it made no difference at all.

Unplugging the electrical connector will do nothing if the EGR is stuck open.

 

[M104]

Battery voltage is fine. Can't remember the reading but it was fine. Voltage was around 14.4v with the engine running.

Unplugging the electrical connector will do nothing if the EGR is stuck open.

I thought about that but figured it would likely be stuck close if not energized.

 

[SC Maintenance]

I thought about that but figured it would likely be stuck close if not energized.

Obviously neither of us know until you take it off. However given it died while idling that doesn’t point to it being closed.

Given it quit while idling, gave you an EGR code, and threw 2 coil codes - a stuck open EGR could explain all those. Worth looking into at least.

 

[M104]

I still don't see how the EGR would trigger about every possible engine DTC at once.

 

[SC Maintenance]

I still don't see how the EGR would trigger about every possible engine DTC at once.

You have only listed 4 codes.

P0406 is the EGR.

P0351 and P0352 are coil codes. Given there not accompanied by misfire codes I already explained how these could be explained by a EGR issue. Not saying they are - but there is a logical path to get there.

P16xx are typically manufacture specific and usually security related. Not sure what to think about that. It could be a voltage issue affecting everything, but I would actually expect other CAN controller codes if that were the case. No idea on Peugeot - never touched one.

So just trying to offer my logical steps. Obviously its your car, I am just an idiot on the internet.

I do wish you good luck however.

 

[M104]

I'll keep you posted when i find what the problem is!

 

[M104]

I did more testing and found that there's no power in one of the fuses once the engine stalls. Went through some diagrams to learn that this is the fuse for injectors, 02 sensors, egr, evap and coils (an other things but i forgot). Pretty sure it will work again once everything cools down. I'm pretty sure the issue is a failing relay inside the engine bay fuse box. Unfortunately it is impossible to repair on this car and i have to buy the whole fuse box. It seems to be a common issue for these cars.

 

[IndyIan]

I did more testing and found that there's no power in one of the fuses once the engine stalls. Went through some diagrams to learn that this is the fuse for injectors, 02 sensors, egr, evap and coils (an other things but i forgot). Pretty sure it will work again once everything cools down. I'm pretty sure the issue is a failing relay inside the engine bay fuse box. Unfortunately it is impossible to repair on this car and i have to buy the whole fuse box. It seems to be a common issue for these cars.

Hmm... Can you just use another circuit with a relay that works? It seems the fuse box itself is good place to add some jumper wires? I've never done it, but as long as everything is fused and not overloaded, and the other relay you use is functioning at the same time as the broken one? What's the difference? I guess you need a circuit that stays on when the starter is engaged, so maybe use the fuel pump circuit to activate an external relay?
I guess I'm used to looking at the fuse box in my 06 Focus with dozens of fuses, and unused circuits, and all the relays are replaceable. The 407 seems to ahve much less fuse slots available. Is yours a manual transmission? Maybe the automatic control circuit is available then?
Or hopefully a replacement fuse box is available for reasonable money, and you don't have to hack something together!

 

[M104]

It is a weird design, not being able to pull any relay out! Fortunately a fuse box for this car is very easy to get, this is an extremely common car here, similar to... i don't know, maybe a Camry in the US?