So, this Fuse 26 10Amp is the memory fuse for the PCM, it should be hot at all times providing constant power to C175B PCM connector pin 62 (Yellow/Red wire).
This would be a wire I would load test with a higher amperage test bulb. Even though memory is not a high current circuit, the dotted line indicates that wire feeds other circuits, i.E. The PCM power relay and the Evap Vent valve, and possible other components as well.
There are also 2 other power feeds and 2 grounds you can see in the 3rd diagram.
I use different turn signal bulbs to load test wires, since they will pull anywhere from 1 to 4 amps depending on how they are set up.
Since it won't run on its own at this point, start with some key on testing, make sure the battery is fully charged up and I like to keep a maintainer on the battery when testing so it doesn't discharge while the key is on, low battery voltage will cause all kinds of issues.
With the key Off and out of the vehicle, you could disconnect the PCM C175B connector to check pin 62 for power, and load test the 2 grounds (pins 69, 70).
This is where I'd start, the cylinder 4 is Pending, and cylinders 7 and 8 are on a different bank of the engine, so it would be really good if this turns out to a lack of voltage issue, just causing the PCM to go nuts.
Theres too many possibilities right now to give a definite answer as to what's happening. But those fuel trims at 0% look really strange too.
The engine might be running on half the cylinders if those injectors are disabled due to codes.
Let's see what you get for voltage readings, if it's low, we can do some voltage drop testing on the power feeds to see if there possible corroded connectors or wiring damage.
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Sunday, February 23rd, 2025 AT 4:50 PM