ottoman35

My 2006 Scion xB is not getting power to the C/OPN relay. I jumped the terminals for the fuel pump and it runs, but when I put the relay back in, nothing is energizing the relay.
From the schematics I found, power comes from EFI relay, then grounds out to the EU, pin FC. The only thing I found is if the airbag is deployed (which is still intact) it turns the fuel pump off.

All relays check out, so what should I check?

Also, the airbag light is on, but has been that way for the last two years.


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RichBinAZ

If your relays are good and jumping the connector makes the pump run, then I wonder if the receiving connector is no longer a tight fit on the relay pins. May have to squeeze down a bit on those receiving connectors.
Probably don't look like this, but may be similar & well hidden inside the plastic base.

ottoman35

Checked the wire from the relay to the ECM and it has continuity.

Could I just bypass the ECM and wire it to a Ground point?

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RichBinAZ

I know this is bike related, but this is what I meant - poor contact between pins


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Birsan

Hi, for this Airbag light Reset, can one fix with out going to a Scion/Toyota dealership? My old car mechanic once say: "On the under-dash is the OBD2 connector. Jump terminals #4 and #13 (paper clip is fine). This procedure may fix also other issues.

ottoman35

Google it. Theres some way to reset the vsc light and other things by jumping connectors on the obd2 port.

DannoXYZ

Don't kill the messenger!!!

So what activates the COPR??? The ECM!
Is trigger-line between ECM and COPR being activated?
If not, why isn't ECM triggering COPR? Did you verify wire between ECM and COPR is OK? How would you know?

Typically ECM must see engine spinning in order for it to activate COPR.
Are your crank & cam sensors sending proper waveforms to ECM?

This is 5-minute fix with oscilloscope...

ottoman35

Everything works. I posted this two days before I realized that. Im used to vehicles priming the fuel pump when the ignition is turned on and not after, lol.

DannoXYZ

Ah good!

Yeah, early injection systems such as Kugelfischer, Bosch D, K, KE, LE-jetronic systems used high-pressure (200psi+) mechanical injection. So pump needed to be started ahead of time to build up sufficient pressure to inject when engine is actually started. But Bosch LH and later systems used low-pressure 45psi pumps, so no priming needed.

Along with regulatory safety changes to FMVSS in early '90s resulted in requirement that pump only runs when engine is running. Otherwise you can get into crash and get trapped in upside-down car. Then fuel-pump merrily continues pumping petrol through ruptured fuel-lines onto hot exhaust pipes and it'll continue pumping until petrol tank is empty.