No bus

[GFB]

Friend's 2001 has been sitting for a while. He said it got struck by lightning. I cannot get any codes out of it, just an odometer flash four times and then displays NO BUS.

Will it need both an ECM and PCM? Do both modules communicate via BUS? Will a used ECM work ok or do they have to be VIN flashed?

 

[TravisG]

Wow! By lightning? That sucks. Not sure what it would need, but you might want to check your connections at the ecm and pcm and see if that helps.

You can use a used ecm but it does have to be vin flashed.

 

[GFB]

Will the truck run at all with a different ECM before the re-flash?

 

[high toned sob]

No Bus could even be a sensor pulling the system down. Disconnect various sensors one at a time then go cycle the key, see if it comes back. Crank sensor, I.P., High side A/C switch, are just a few of them that can cause NO BUS.
PCM/ECM could do it, you could also pull the communication single wire out of the connector and cycle the key to isolate the module.

thanks,
mike

 

[4x4dually]

Swap a buddies PCM and ECM into the truck and try that before you buy new ones. They should run. You are missing the CAN Bus either out of the ECM or PCM or both. If you get a new or used ECM, you will have to have the VIN flashed. If it is different than the VIN in the ABS module, your CEL will always be on. $.02