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Ecu/Double relay problem
#1
Hi guys (and womens) ?. (sorry for my spelling, im from SWEDEN)

I try to help my friend with his peugeot 306 2.0 16v 1997 convertible .
ECU Bosch mp5.2
He got it from his past away uncle, it has been standing still for 2 years.


Battery was dead, bought a new one and put it in.
Engine cranks but dont start.

I have found a problem with the double relay.
The side of the relay that starts the fuelpump dont get a negative signal. (pin 10 if i remember correctly).

I have read so many threads on different forums but cant find what causing this problem.

I read somewhere that the negative signal should come from the ecu. I have found a cable from pin 10 in the double relay that goes to the ecu connection pin 3. Beeped it with 0 ohms so the cable is okey.



I have checked negative connections in the Engine compartment, i have checked all fuses.

Fuel cut off switch works.

Any ideas what to check next?

Here is schematic.
https://ibb.co/ww1J8Ny
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#2
if there is no grounding from the ecu to turn the relay on, the ecu may not be seeing a crank signal, or the ecu may not be powered up or possibly not unlocking with the keys
need a part number? http://public.servicebox.peugeot.com/ and http://service.citroen.com/ will sort you out.
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#3
Hi, thanks for input!

I measured the incoming power to the ecu pin 18, +12V.
I got earth on pin 2, 14 and 19.

The fuel pump is not priming when key on, thats sorts out the crank signal i think?

I cant find info on what the Immo does to stop the car from geting fuel. Dont know how to find out if the Immo is the answer or the ecu or something else.

Its very expensive in sweden to send the ecu to reperation so want to be 100% sure before paying.

I got no Peugeot Planet and dont know enyone who has Sad.

Tried 2 different obd2 readers (one cheap from China and one expensive KIA Kds) no connection to ecu Sad
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#4
With everything you've done so far I'm assuming you've got access to ECU pin data & wiring diagrams? As far as I can tell you can only go as far with testing without either PP or sending off the ECU.

Pin 8 on the immobiliser is connected to pin 3 on the double relay & pin 34 on the ECU.  In Autodata though, the info for testing the immobiliser only mentions Pins 22 & 35 on the ECU, and it doesn't give any test data for pin 22. Pin 35 should have 11-14v with ignition on.

You could bypass the double relay to get the fuel pump running but I assume if it is an immobiliser issue the ECU won't control other items like injectors & the coil. Tbh though, I don't think I've ever seen anyone definitively state which signals from the ECU are supressed in a locked ECU, so I have no idea really.

The crankshaft position sensor connects to pins 11&30 on the ECU if you want to test the integrity of the wiring. On the sensor itself you should get 300-400 ohms across pins 1 & 2. The same pins should give 1 - 4 v ac fluctuating voltage with the engine turning over.

If you get to the point of wanting to send off the ECU for testing (& if necessary unlocking) & would consider sending it to the UK , I've found these guys to be very good. https://www.cartechelectronics.com/. They also have unlocked ECU's for sale, although they really aren't cheap. The 0 261 204 652 was for the slightly later XU10J4R (with 200cc injectors & plastic valve covers). The earlier version with 186cc injectors (& alloy valve covers) was Bosch number 0 261 204 689. (Weirdly the earlier one had the higher serial number!).

Just looking again at the wiring diagram, I am wondering if pin 3 on the double relay is a power out to the immobiliser & the ECU (pin 34) via pin 2 on the double relay?

There's also a connection between the engine check light on the dash (illuminated at ignition on), pin 9 on the immobiliser & pin 22 on the ECU. Power to the dash check light comes from fuse 2 (5 amp).

Are you getting an angine check light illuminated with ignition on?
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#5
Hi!

Busy weekend, but now Im on it again ?. 

I bought the Haynes repair-book. It sucks!
Wiring diagram dont match this car Sad

Only diagram that match my ECU is this https://ibb.co/ww1J8Ny.
Think ut Spanish or something but Google helps out!


Cant find pin 35 in this diagram :o, will take a better look at it tomorrow.


Crank position sensor will be tested tomorrow, good input, thanks! 


I would definitly considder send the Ecu to uk, the price for a unlocked one is the same for a reparation without unlocking here in sweden. 

Ive got this one: "The earlier version with 186cc injectors (& alloy valve covers) was Bosch number 0 261 204 689" 

I got check engine Light illuminated with ignition on, checked every fuse i could find. 


My pin out diagram is missing the part were they discribe what the * (+15* for example) means. 

But you may hace cracked it for me Smile

I hope you are right about
"Pin 3 on the double relay is power out to the immobiliser & the ECU (pin 34) via pin 2 on the double relay".
Checking that tomorrow! 
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#6
The Haynes manual doesn't have a full set of wiring diagrams, by any means, and some of them are general rather than model specific.

I signed up to a 1 month trial of Autodata. (Cost about £12 in the UK). Worthwhile if you want to download a full set of decent wiring diagrams. (You do have to make sure you request a cancellation before you enter a second month of subscription though, otherwise you'll be contracted for another 12 months & it's then very expensive).
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#7
Hi guys!

Havent had time to look at the car for a long time now but yesterday i took a look at it.

Ive measured the crank position sensor and it was broken, put in a new one and the car did start at once. Smile

One thing i noticed was that the fuel pump didnt prime with Ignition on, the pump started when i cranked.

Thanks for all your help!
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#8
Great to hear you do it sorted Smile
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#9
Hi to all, Im a new member. Im facing the exact same problem, 2.0 liter RFV Bosch mp5.2. Im not getting ground from pin 3 of the ECU when I turn ignition on so no fuel pump power or coil pack power. I have mearured the crankshaft position sensor but it gives me arroud 320 ohms so it is allright.? I have tested all this post says but with no luck. Tried with two ECU already. I'll apretiate your help
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#10
Welcome to the club. Firstly, I'm going to assume the pin out's on the ECU & other attached components are the same on the 306 version as on the 405. (I'm working off 306 wiring diagrams for the RFV).

As I mentioned in a previous post above I don't know which pin out's from the ECU are dependent on the security module functioning correctly (sending the appropriate signal to the ECU). The ECU is just a 'black box' on the wiring diagrams. If I were a gambling man though I'd say a lack of ground on pin 3 is security related. Without it the side of the relay that controls power to the coil pack & fuel pump (via the fuel cut-off switch) won't activate.

Two questions ...
1) will the car start if you provide a ground to pin 10 of the double relay?
2) When you say you changed over the ECU, have you tried one that has been unlocked?
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