The code found is u1421 implausible ignition key off time recieved. This is not a common code. Here is the actual test for the code. Note: it requires the factory scanner to check it and the other control modules for any other possible codes:
For a complete wiring diagram Refer to Section 8W.
The fuel volume message the ECM is receiving is implausible. The circuit is continuously monitored. One Trip fault.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
The Totally Integrated Power Module (TIPM) isn't receiving a fuel volume signal over CAN B from the Cluster Module. The TIPM has to send the PCM a fuel volume signal over CAN C. The signal the TIPM sends over CAN C is implausible.
1. ACTIVE DTC
Ignition on, engine not running.With a scan tool read DTCs.
Is the DTC active at this time?
2. CAN B BUS HARDWARE DTCS ALSO ACTIVE
With a scan tool check for DTCs in the TIPM.
Are any CAN B Hardware related DTCs active at this time?
It appears the issue will be the engine controller however it all depends if there are any other codes found. Let me know if you need more help or have more questions.