2 fault codes - help needed

[Guv]

I've run a diagnostic check on my 1998 Mondeo ST24 and it's picked up 2 stored fault codes.

1) P0401 - Exhaust Gas Recirculation Flow Insufficient Detected.

2) P1131 - Manufacturer specifc code. This looks to be the front lambda sensor from what I've found out.


I have no idea what the 1st code is about and so have no idea how to fix it. Any help here explaining what it does and how to fix it would be great.

I understand the lambda sensor fault but haven't looked at how hard they are to replace yet.

 

[Dandle]

The P0401 code is "Exhaust Gas Recirculation Flow Insufficient Detected" and the probable fault is "Hose leak/blockage, basic setting not carried out (if applicable), wiring, Exhaust Gas Recirculation (EGR) valve, Exhaust Gas Recirculation (EGR) solenoid, ECM"

The P1131 code is "Lack of HO2S Bank 1 Sensor 1 Switches - Sensor at Lean Limit". Which sounds like a lambda sensor to me.

Hope that helps a bit.