Fault codes

[tomdog]

2017 TXI 6 liter 409 hp

Fault codes on the dash as follows

Fault 1

SPN 3256

FMI 5

What do these codes mean ?

[justgary]

Please don't double post your issues....

[oldjeep]

O2 sensor fault.  Open/lazy 

 

[23LSVOwner]

19 hours ago, tomdog said:

2017 TXI 6 liter 409 hp

Fault codes on the dash as follows

Fault 1

SPN 3256

FMI 5

What do these codes mean ?

https://lmgtfy.app/?q=spn+3256+fmi+5

[csleaver]

A quick way to troubleshoot the issue is to swap the rear most post catalyst O2 sensors on the port and starboard exhaust pipes.  If you continue to get the SPN 3256 FMI 5 code then there is a connector, wiring, or ECM issue.  If it changes to a SPN 3266 FMI 5 code then the O2 sensor is probably faullty.