NSeagle78

iTrader: (5)

I just replaced my transmission. However my car is throwing a code 21 Main 02s and heater signal. I ordered the upstream sensors from advance auto and they should be in tomorrow morning. Do I do any cleaning connectors and do I clean the slot where the sensor came from prior to installing. Also what does heater signal mean? Also my car is not throwing out good heat. It does get cold in Georgia. My car stalls at starts and at interstate highway speeds. Help

mitsuguy

iTrader: (2)

The heater for the O2 sensors is just that - it is a heating element built into the O2 sensor - they are more accurate when warm, so the heater helps the O2 sensor become more accurate, sooner... The heater circuits are very simple - power and ground, if the ECU is throwing a code due to a heated O2 sensor issue, the problem is most likely the O2 sensor, but a wiring issue or ECU are the only other two possible culprits...

No heat - is the coolant level sufficient? Does the gauge on the dash register normal operating temperatures? Most likely causes are low coolant and stuck open thermostat (remove it, put in pan on stove, observe temperature at which it opens, should be 185-190 it starts to open, full open by 205-210... If the thermostat is operating properly and coolant level is correct, you may have a blocked heater core - reverse flushing this may help...

Stalling at starts and highway speeds both - most common issue is idle air control motor, but hard to say, could be a lot of things...