Codes keep showing up

613059

{"text":"Good morning I have a 09 Western Star series 60 Detroit I've replaced the engine wiring harness and all sensors I keep getting code's 15 and 21 code 15 is oil or coolant temp sensor voltage High code 21 is TPS sensor I have also cleaned up the grounds on the firewall I have also cleaned all the connections on the engine in the MCM and the engine also check for corrosion on the plugs on the firewall not sure what else to do any suggestions from anyone thank you","pics":"[]","canComment":false}