So i was driving into town the other day and got a water in fuel light on the dash and the truck started bucking like i was turning the key on and off over and over again. It smoothed out and I pulled over, drained some water/fuel out. Started it up and drove another couple miles and the truck started bucking again. It ended up dieing this time and wouldnt crank. I pulled a p0562 code and cleared it and no change. All the guages, windows, radio, hvac, lights and everything else seem to work. There is no gear indicator showing on the dash or change in gears when I shift through them on the minimaxx. The code reader and mini still communicate through the OBD port. The solenoid wire is not getting 12v but when I send 12v to it, the truck cranks but wont start. It has new batteries, all fuses and fusable like are good. The red security light stays on for a second when i turn the key forward. Im thinking its the PCM or ECM. Can someone shed some much appreciated light on this issue?

 

Thats a system low voltage code. Could be a bad battery, bad battery connection, bad battery cable, bad alternator. Check all your connections and cables thoroughly.

the symptom suggests get both batteries tested, as it was running low on voltage as this all started happening. Remember to test the batteries individually. If both batteries check out ok, have the alternator tested.

If the alternator hasn’t been doing its job, both batteries will test low. But will usually accept a charge. Charge them both to full capacity before further testing.

 

How did you figure it out ?

 

It sounds like the truck might not be recognizing the key, which could point to an issue with the anti-theft system or a problem with the PCM/ECM. The red security light staying on is a clue. If the anti-theft system is active, it won’t let the truck start even if you manually crank it.

Here are a few things to check:

Check the key and ignition: If you have a spare key, try using that to see if it makes a difference. Sometimes the chip in the key can fail, or the ignition reader might not recognize it.

Battery connections and grounds: Even with new batteries, make sure all the connections are clean and tight, especially the grounds. A weak ground can cause communication issues.

Reset the anti-theft system: Look up the reset process for your truck's anti-theft system. It usually involves turning the key to the "ON" position for a set time (like 10 minutes), then off, and repeating the process.

PCM/ECM check: If none of the above works, it’s possible the PCM or ECM has failed. Before replacing it, make sure the connectors to the PCM/ECM are clean and seated properly. Corrosion or a loose connection can cause this problem.

If you still have no luck, you might need to take it to a dealer or a mechanic with the tools to reprogram or replace the PCM/ECM. It’s worth ruling out the anti-theft system first since it’s a common cause of this issue.