06 envoy codes

[Shannon]

P0480 AND P0128, could these codes be just something as simple is changing a thermostat?

[carriedi]

P0128 says the engine is running too cold for too long. Or just taking too long to warm up. P0480 could be tied to this code too. Most of the time changing the thermostat is the fix for P0128. Clear the codes and see if the P0480 returns.

the code P0480 is a computer code that says the computer sent a signal for the cooling fan relay to turn on the cooling fan but the cooling fan actual state does not match. The code sets after the second consecutive trip the condition happens for over 5 seconds. the engine cooling fan clutch is a common fix. Use a scan tool and command the fan speed to increase and see if the speed increases. then go through and see what is happening with the fan and it's circuit.