Here are some troubleshooting tips i found from one of their online conference sessions for this code:

- Can Line test Connect between 86 and 94 reading should be 61 ohms (Higher means you have a
open resistor)
- Check for corrosion in both data connectors under the cup holder on Tier 3 trucks
- Check black fuse holder under the main injector.
- Check for blown F9,F10,F11 fuse
- Check EGI relays and Main C relay in the blue relay box.
- Check ignition relay. Black box in left side step plate
- Wiggle wires. Look for chaffed, pinched, cut wires along right or left step plate area.
- Codes E04 and F04 Hour meter comes on with the key switch on and not running. Still cannot
access the ECM
through the VCM and diagnostic program. Dealers in some cases replaced the chassis harness.
- Diagnostics will not communicate either. MP panel is also having communication problems as
well.
- We have sometimes just cleaned the pin connectors at the ECM or VCM.
- Washing the truck will also cause this code if water gets into the VCM connector.
- Failed VCM
- Injection driver failed blowing QGS fuse.