Cranks but no start (codes P0688 and P0522)

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garagecouple

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Those sensors are nothing more than switches, they either work or they don’t.

A14 does not go to the fuel pump, that is the output to the PCM. The fuel pump relay is totally independent and controlled by the PCM.

If A13 & A15 were connected together the relay would always be energized.

A11 - Control ground from PCM
A13 - Switched ignition 12v
A15 - Fused B+
A14 - Switched B+ to PCM, Coil, Injectors
Not to complicate things further. Want your input on this. Let's assume the ASD relay DOES NOT click during the initial 2 second start up, what is your thought process there? I would think somewhere from the PCM to the ASD ground the wire is interrupted/damaged/shorting Hopefully all of this information helps a frantic googler sometime in the future. Thanks again!

I had asked my wife to check with her fingers, but she may have just felt the fuel pump clicking. Not near the jeep now so unable to verify. Just trying to get my next steps ready as I wait.

Thanks
 

1RAD

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You have verified the 12v sense to the PCM is good with a jumper.

You have exchanged the relay with a known good one.

That leaves the ground from the PCM as you suggested, the 12v from the ignition, or possibly the relay socket not making good contact with the relay.

Have your wife turn the key while you monitor the relay, or simply remove the fuel pump relay so that there is no mistake.
 
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garagecouple

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You have verified the 12v sense to the PCM is good with a jumper.

You have exchanged the relay with a known good one.

That leaves the ground from the PCM as you suggested, the 12v from the ignition, or possibly the relay socket not making good contact with the relay.

Have your wife turn the key while you monitor the relay, or simply remove the fuel pump relay so that there is no mistake.
Thank you for your reply! I will verify myself the relay function and get back to you. Wondering if the 4 o2 sensor codes it threw when I jumped the relay indicate the pcm is dead and that I need a new pcm.
 
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garagecouple

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Ok, so the ASD relay circuit has passed the pre-start test, it’s important to verify that the relay is again closing during cranking.
This is important because it will indicate that the cam and crank sensors are functioning.

* During cranking if the PCM does not receive a valid cam or crank sensor signal it will not close the ASD relay. The ASD relay supplies the power to the coil, fuel injectors and O2 sensors.

If the ASD is closing while cranking and you have verified that the correct voltages and grounds are present, the you will need to have the PCM looked at.
I have an UPDATE! We did it! Fires up, but now is throwing the 4 02 sensor codes (p0031, p0037, p0051, p0057). I got it to run and I could not have done it without your help and the help of everyone else who has chimed in! Hopefully this thread helps someone struggling with this issue down the line!

Upon further inspection, my ASD relay WAS NOT clicking during that 2 second interval. I followed that brown/white wire all the way from the PDC to the terminal in the PCM (closest to the driver), and believe it or not, it was completely cut right before the pin! I reconnected the wire, and then used electrical tape to cover some of the other wires nearby, and it fired right up. I noticed in the ECM connector in the middle, there were three wires with exposed copper. I went ahead and covered each of them with their own electrical tape. I'm thinking maybe one of them is a ground for the oxygen sensor and thats why I am getting all 4 of the o2 sensor codes at once?

Any advice with the wiring of the oxygen sensor? Where would you look if your Jeep threw all 4 codes at once'? The jeep is firing right up and idles just fine. Haven't taken it on a drive just yet.

Thank you so so much!
 
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garagecouple

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So to update. Jeep runs and drives. All 4 of the oxygen sensor codes come on immediately and the jeep idles and drives fine. All 4 of them read voltage values above 1.1 all the time. All 4 of the connectors have a continuous ground to G105 tested with a multimeter. At this point I think its the PCM. what else could cause all 4 o2 sensors to throw codes at the same time? What to check next?
 

1RAD

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So to update. Jeep runs and drives. All 4 of the oxygen sensor codes come on immediately and the jeep idles and drives fine. All 4 of them read voltage values above 1.1 all the time. All 4 of the connectors have a continuous ground to G105 tested with a multimeter. At this point I think its the PCM. what else could cause all 4 o2 sensors to throw codes at the same time? What to check next?
1.1v. Where? Heater voltage? Signal voltage?