406oc.co.uk

Hi,

I have a Peugeot 406 1997 ST Auto 2.0
ECU = Bosch MP5.2, OE Ref Num = 0 261 204 696

I've been browsing this forum and came across some similar issues.
Putting into simpler terms, I would just call it,

A no start due to the 2nd ignition relay (Voltage input = pin 2, Output/ground = pin 10) supplying fuel does not close on ignition switch on.
Pin 2 has +/- 12 V on ignition on
Pin 10 has NO GROUND.

1. From the circuit diagram (http://peugeot.mainspot.net/wiring406/index.shtml), pin 10 comes from the ecu pin 3.
2. Tried grounding ecu pin 3 and relay DOES close. So its not the ecu-relay wiring issue.

Help anyone? Looking at the ECU i see no burnt marks. Or can i be wrong? TDC? I don't even know what that is.

Thanks in advance

Hi there, welcome

Umm, TDC - top dead centre, this will be referring to a sensor on the converter housing seeing magnets or a missing tooth on the starter ring gear to tell the ecu when the crankshaft is at tdc. I guess if it's got no output then the ecu can't tell if the engine is turning or not.

See item #6 on this diagram - http://peugeot406coupe.nl/catalogus/D8F/1/19G25A.HTM (not sure if this is the same motor as you have there but the principle is the same)

Hi & welcome aboard.

Does it have a fuel shut-off switch / have you checked it?

Somewhere in the engine bay, usually bolted to the struts is an inertia switch. It's usually red and rubbery!

Sorry, should of stated that also.

Checked the inertia switch and its closed.
Once i ground the pin 10 on the relay, the fuel pump is heard running on ignition.
So its surely something from ecu.

Gonna have a look today. Wish me luck boys.

I had a similar problem with a Citroen Xsara HDi 90. The fuel pump would not run, or only run sometimes. I changed the double relay, it made no difference. I got it working temporarily by bypassing the ecu to make the pump run, as you have.

Discovered 1 of the 3 +12V supplies to the ecu was missing - this was the power for the egr valve and fuel pump relay.

It turned out to be a fault in the wiring loom that I never found. I overcame the problem by linking two points that should have been connected but no longer were.