HEGO is heated exhaust gas oxygen sensor or 02 sensor. or oxygen sensor, they call them by many names
Your truck has 4 of these sensors
There are two banks, drivers side and passenger side. Pass side is bank 1, drivers is bank 2
There are two sensors upstream of the cat converters (engine side of the converters) These are bank 1 sensor 1 (B1S1) and bank 2 sensor 1 (B2S1)
and two sensors downstream of the cat converters (exhaust side, after the converter) These are bank 1 sensor 2 (B1S2) and bank 2 sensor 2 (B2S2)
Your mechanic was talking about the downstream 02 sensor, they can be referred to as "catalyst monitors"
the two upstream sensors are responsible for telling the computer how much air remains in the exhaust and the computer uses this info to tune the amount of air and fuel needed. These two sensors are also "pre heated" by the computer at start up, so instead of waiting for the exhaust to get hot for the 02 sensor to function properly the truck uses battery power to pre heat them/ It is quite common for things that have a heating element in them to wear out or short. So HEGO sensors usually last 100-200K miles before they melt down, the heating element goes out, or they cause a dead short and blow fuses. Either way once a HEGO heater circuit has a failure we get codes from the computer
Now this does not mean you run right out and replace all 4 02 sensors............. the 02 sensors are sometimes just dong their job. In your case they are reporting a very rich condition
The two downstream sensors do not do much, they simply monitor the function of the cat converters making sure they are burning up any unspent fuel. The mechanic must have replaced one of these sensors, and as he said they are simply monitors.
Your codes 1132 and 1152
Error Code
P1132 is described as Lack of Upstream HO2S (Heated Oxygen Switch Sensor) Rich Bank 1. Meaning, a rich HEGO (Heated Exhaust Gas Oxygen) sensor indicates a rich condition at the end of a test that it's trying to correct for over-lean condition
P1152 is the same code for bank 2
READ HERE:
The Heated Oxygen Sensor (HO2S) Monitor is an on-board strategy designed to monitor the HO2S sensors for a malfunction or deterioration that can affect
www.autocodes.com
So the computer is NOT SEEING the two upstream sensors switching.
First thing I would do is CHECK FUSES
The lack of switching on two sensors at the same time is usually a power issue, meaning the HEGO sensors are not pre heating or being "powered up"
Without fixing these codes your truck will not run properly.
CHECK FUSES, especially ones that have to do with oxygen sensors (HEGO)
Check wiring to the two 02 sensor upstream of the cat converters
With your two codes it is not very likely that both upstream sensors have failed at the same time, it is more likely a fuse or wiring issue
yes if I replace one primary converter I replace them in both banks. Although it is possible to ruin one cat converter by dumping raw fuel into them, if you are going to replace one, replace them both.