My truck is showing a “no bus” error with several dash warning lights staying on, including security light. It will not start and seems like the security immobilizer has kicked in (won’t even turn over).
This started just after I replaced the a/c compressor. We found out that the coolant had not all leaked out when my nephew removed the lines. It sprayed around the engine compartment. At first, I was able to start it the next day but when I shut it off and tried again the error message came back. It also started a couple more times but shut off within 10 seconds.
Dash lights all seem to work, but controls on the steering column don’t function (no 4-ways, turn signals, etc). The radio does not work and it doesn’t seem to respond to the headlight switch or transfer switch either. Didn’t think to test the horn.
Windows and door locks all function.
I’ve tried to make sense of the rat’s nest under the dash. Tried to see if there’s power coming in with a check light for the 4 ways. There is a connector there that has 4 wires, 3 show power coming in. Not sure why it would need 3 powered lines.
OCB2 codes show U1403 (twice) which is for fuel level sensor. Don’t see why that would be a problem.
Sometimes the alarm sounds when the door is open with the key on, sometimes not. The headlights usually come on and stay on until the key is turned off and door closed (after 30 seconds).
I took out the battery. It is possibly the cause of the problems as it doesn’t seem to hold a charge anymore. I tried a deep cycle boat battery to see if it made any difference but no dice.
I removed the TIPM and cleaned the connections. There is one connector that has corroded but I don’t know what it controls. Since I’m getting power to the 4-ways, I suspect it isn’t a power issue, but I could be wrong.
I removed the battery tray and visually inspected all the wires from the dash to the TIPM and/or grounds. I found a couple wires that had been abraided, but not broken.
I’m at a loss of what to check here. I know it could be the PCM or one of the wires running to it along the firewall, so I’ll have to check those as well. But the only tools I have are a check light, multimeter and my weary eyeballs. I have no idea how to check the PCM or TIPM and I don’t want to spend money fixing something that ain’t broke ('cause I am).
Is there anyone out there that can help me diagnose this? What should I be checking? Do the dash indicators that stay lit have a clue to help?
Thanks for your time and help!