Help! No power to OBD2, nor horn, nor starter...

[Mountain]

Hi folks,

I'm stumped!

2005 Eddie Bauer Expedition, ~140K. Recently replaced the fuel pump control unit due to corrosion & a short. That got 'er up and running. At this time I repaired a leak in a brake line, bled lines & brake seems to be OK considering that now the engine won't crank. A check w/ an Actron scanner showed no link, indicating no power to the OBD. Here's the run-down in case anyone has an 'aha' for me:

-No link / no power to OBD2
-Relays click, but engine won't crank & no horn either. Replaced relays, no change.
-Checked all fuses. None bad & cigarette lighter works.
-All fuses had power when they should have had power.
-Pulled neg lead on battery for long time, no change.
-Tried locking / unlocking w/ key fob and keypad entry. Also pushed panic button then again to stop. Locks & unlocks ok, but I only hear the relays click when the horn should be honking.
-The dash warnings show 'Low tire pressure' (yes, I need to inflate one), 'Engine temp data error', and 'Charging system data error'.
-Battery is relatively new and fully charged, ~12.5 volts or more.

Any thoughts? Trying to fix for the family before I must go overseas for work. Thanks

 

[stamp11127]

Check and see if the starter relay is getting power to the control side when the ignition switch is in the start position.
And I'm going to assume you checked the fuses with a meter or test light instead of just looking at them.

 

[Mountain]

Thanks- yes, checked with a meter.

If starter relay is clicking when I engage the starter, can I assume it's getting power?

 

[stamp11127]

All that means is the control side is getting power. Next check for power on the high currant or load side of the relay, at the relay posts when in start position. Should have battery voltage on both large terminals.

 

[05expedeb]

Recheck fuse 26 and 41and 101

 

[bavism]

I recently had a no crank/ no start issue and it turned out to be the PCM power relay. You can swap the relay with the one next to it "fog lamp relay" to see if there is an issue with the PCM relay.

 

[Mountain]

Thanks everyone for the ideas so far. I have re-checked all fuses & relays. I had replaced relays before including the PCM relay / fuses, but swapped & rechecked just to be certain. No luck!

So the relays are at least getting control voltage. I may need to loosen the panel to check if the power side is getting voltage.

Still stumped because it's the combo of OBD, horn, and starter lacking power. Plus the engine temp data error and charging system data error.

 

[stamp11127]

Don't focus on all the issues. Tackle one at a time. Swapping relays really doesn't prove anything unless you know the circuits have power. It would be similar to changing a lightbulb with the wall switch off. Pins 85/86 are the control side of the standard ISO relay, starter relays it is the smaller studs.

 

[Mountain]

Solved!

After eliminating just about everything else, I took another close look at the fuse panel. While checking all the connectors I found that the uppermost left connector was not fully seated in its socket. I more or less had to lay my head down on the passenger floor mat to see this. A little more robust push than I had done before resulted in a satisfying 'click'. Probably due to an engine swap a few months ago (sudden cam phaser failure at highway speed). I'm guessing it was not fully engaged at the shop.

Thanks again. Now to lurk and possibly help someone else in the future.

 

[05expedeb]

Thanks for the update.
That connector is C270a