Hello and welcome to Just Answer!
P0891 sets in the TCM when the TCM senses there is more than 3 volts on the transmission relay output wire when it hasn't energized the relay. This is usually caused by stuck contacts in the transmission relay. Would you be able to swap the EATX(transmission) relay with the horn relay and see if the horn blows steady when you swap the relay. The relays are located in the fuse box in the engine compartment.
Let me know and we can go from there!
yes sir, i tried that and the horn did not stick.
Can you erase the codes by disconnecting the battery negative cable for a minute and then see if the code or problem return? The relay can stick intermittently and I would like to know if the problem is still there.
Thanks, XXXXX XXXXX know and I will get back to you asap!
ok, i did that, drove it around the block and it came back on. it is driving fine and shifting fine.
Can you see if it still has the same code?
Lets try this - Sit in the vehicle with all doors closed and starting with the key in the off position, turn it to ON, OFF, ON, OFF, ON (don't turn the key to the start position just on) within 5 seconds and leave the key on and watch the digital odometer to see if it displays a fault code. It will be a P followed by 4 numbers example P0700. When it is done displaying codes or if there are no codes it will say done. If you can't get this to work, please try it again following the instructions!
This means you either have a wiring problem or an internal PCM problem.
Do you have a digital multimeter and could do a few tests for me?
You are very welcome!
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