codes p0141 and p0161
 

Someone please tell me what these codes mean. is it to do with the 02 sensors or the heating system? once again i am a first time ford owner and a few folks on here have been very helpful. our heat is hardly working. thanks in advance. this is on a 98 ford f250 4.6 vin code w
:eek:

As usual, Google is your friend, just search for the code number and the keywork OBD2 (for instance, search for "p0141 obd2"). Here are two pages showing what these codes mean:

OBD-II Trouble Code: P0141 Oxygen O2 Sensor Heater Circuit Malfunction (Bank1, Sensor2)
OBD-II Trouble Code: P0161 Oxygen O2 Sensor Circuit Low Voltage (Bank2, Sensor2)

Both codes refer to problems with oxygen sensors used by the PCM to control the engine. These codes should have nothing to do with the cabin heating system - most likely, the two problems are unrelated.

The oxygen sensors monitor the oxygen content in the exhaust gases and provide feedback to the PCM about the current fuel-air mix ratio: too much oxygen means too little fuel (lean mixture), and too little oxygen means to much fuel (rich mixture). The oxygen sensors compare the amount of oxygen on either of their sides (one internal, stuck in the exhaust pipe and exposed to exhaust gases, and one external, exposed to open air) and report the difference as a voltage. The larger the oxygen content difference, the lower the output voltage. In order to measure the oxygen content, these sensors need to be hot - so modern sensors come with an internal heating device - a resistor - that brings them up to normal operating temperature fast, to minimize the amount of time during which the engine runs "blindly" and pollutes the atmosphere more than it should.

Too little heat in the cabin can be caused by a mechanical malfunction of the cabin heater unit (the blend door stuck on cool - google "blend door" to find a diagram showing how the cabin heater/cooler unit is made and how it works), or, more likely, from an air bubble stuck in the cabin heater core hoses somewhere, preventing the hot coolant from circulating normally. The latter usually happens when your engine cooling system has not been properly filled or is low on coolant. Most engines would have a way to vent the air during coolant filling - either by removing a vent screw or a hose, and filling the radiator with coolant until no more air comes out of the venting point. This venting point must be located at the highest location of the cooling circuit - again, each engine is different, and I've no experience with Ford trucks.

Hope this helps ...

Cheers,
cougar_fan

... oops, I just picked up an error - the previous phrase should read: the higher the oxygen content difference, the HIGHER the voltage. Your sensors will output a higher voltage as the oxygen content in the exhaust gases drops. The easiest way to remember this is to look at the sensor's output as if it were the fuel content of the mix: more fuel - richer mix - higher voltage. Sorry for the error, it was 3 AM last night when I wrote that :D