I know how to do a continuity test. I'm an engineer. I'm trying to find out how YOU did a continuity test, so I can help you. I have no idea if you know what you are doing or not. You might, or you might not. You might not, but think you do, in which case, you'll draw wrong conclusions.

 

I'm not an engineer, but I can see there are over 180 posts to this thread and it isn't fixed yet, so, I am going out on a limb and saying...
Nah, I'll wait for it.

 

No, I don't think I know what I am doing because I don't, for the most part.

 

Well I certainly apologize for being a co-conspirator in the "Exceeding The Number of Posts Without Finding A Solution" Forum Rules Violation (Title VIII, Chapter 57, Section 5.5, Part 6.7, Sub-Section 428.1 - "Thou shall not perform ungodly acts with barnyard animals").

OK maybe that's not the right Forum Rule...

Would it help if we deleted the comments about Gal Gadot and Sofia Vergara?

 

So if I'm visualizing your test correctly, this test shows that those wires are in flawless condition.

IMO you should test who is hot on the F22 14OR circuit. With relay out and key off, check it at the EGR solenoid, the fuel injectors, power steering pump, and the fuel pump. Recheck the Oxygen Sensor Heater and AC (you previously got power and no power, respectively for those 2).

 

Did you try changing out the ECU as noted in your other thread?

With the ECU unplugged, see if the Oxygen Sensor Heater still has power with KEY Off. With nothing obviously smoked in the ECU, I'm thinking any remaining ECU issues would result in stuff NOT getting power, rather than getting power inappropriately.

 

BTW what scale were you using? All metals have some resistance, so perhaps you needed to be on a more sensitive scale (although for your test, knowing that it isn't OL is plenty).

 

I did plug in the other ECU... no changes.


Great tips. Will make those tests next.


Had it set to continuity.

 

Forgot to mention regarding the A/C wire switch, I switched the yellow/black and green wires back to their respective colors with no ill effect. A/C still works.

 

By relay out, I assume you mean the O2 relay. Testing voltage to the EGR solenoid is zero, fuel injectors is zero and fuel pump is zero. O2 heater wire is also zero.

Supprise, New Test Results Today.

Tested power at fuel pump connector. Key off got no power. Key on got power. With the jumper wire out, there was no power to the fuel pump connector with either key on or off.

Checked power to O2 with key off, key on and start. Like before, I had 12v with key off, but it dropped to 0v with the key on while the fuel pump was priming. Once the fuel pump stopped priming after 2-3 seconds, the o2 voltage went back to 12v. Started the engine and the O2 voltage dropped to 0v again. Something new engine running o2 gets no power.

The way I see it, there is something wrong with the F22 14OR circuit because pin 87 on the fuel pump relay should not have any power with the key off.

Suspecting there is a short in the F22 14OR circuit causing pin 87 to be hot. This in turn is causing the O2 to pull voltage from the battery.

Also, with the fuel pump relay and O2 relay sharing the ECU ground, the computer cuts ground to the O2 relay for the heater to turn on, but the relay is still energized from the fuel pump relay ground.

Likely, the O2 heater will never work until the o2/FP jumper wire mystery is solved.

 

Actually, that test is showing there ISN'T a short, because everything on that list should have been hot.

With all relays in, jumper out, and Key OFF, test for power at at the EGR solenoid, the fuel injectors, power steering pump, fuel pump, oxygen sensor heater and AC.

If none of them have power, try the back-up ECU as I'm thinking A5 is broken.

If any of them have power pull the plug on the ECU and see if they still have power.

Pull the covers off the ECUs again and note the uF of the 3 radial capacitors in each (why are 2 of them orange)? Are any of them bulging?

 

Oh, there you are!

Sorry, I lost this thread. Forgot which one it was, actually, and had trouble finding my way back.

I'm suspicious of your continuity test. A reading of ZERO ohms is just hard to believe. You should see a few, at least. Two questions:

1. What resistance (ohms) range did you use for the test? OR is this an autoranging meter? (I hate autoranging!)
2. Was the battery connected or disconnected when you performed the continuity tests? It should be DISCONNECTED and time allowed for any capacitors to discharge. (And you have a few pretty good sized caps in your PCM!)

 

Not an auotrange. Thought about getting one but I like being able to choose settings and since you don't like them I'll pass.
Had meter set to continuity.
I did the continuity test between the wires in question and where they ended up at the ECU connectors.
What are caps? I got two ECU's as the FSM calls them, and all the components are the same on each, for the most part, so I don't think any of them are out of the ordinary.

 

Only the o2 sensor had power. Disconnected the ECU and still got power. Cannot check power steering because there is no electrical plug to it.
What is there to check on the AC? The only connector plug is to the clutch bit it works fine.
Pulled ECU covers and inspected real carefully. Some of the orange capacitors, don't know why 2 of them are orange, were thinner than others but were exactly the same on both. The cylinder shaped capacitors had no bulging. In fact nothing at all looked bad.

 

Yank the Oxygen Heater Relay, with Key Off and jumper out and see if the Oxygen Heater still has power. See if Oxygen Relay Socket 30 is hot without the relay in.

Sorry, that's only on the 2.5 L (High Pressure Switch).

The orange on the Clutch relay should be an F22 14OR, and it sounds OK.

Are all the capacitors 220uF 25V?