P2032 code definition
Exhaust Gas Temperature (EGT) Sensor Circuit Low Voltage Bank 1 Sensor 2
What the P2032 code means
This code indicates there is a problem with the catalytic converter or the system that monitors the efficiency of the catalytic converter. The EGT sensors monitor the exhaust temperature before and after the catalytic converter. “Bank 1 Sensor 2” refers to a specific sensor at a specific location in the exhaust stream. The typical operating temperatures of a catalytic converter are from 600F and 1600F. The EGT sensors are key components to ensuring that the catalyst system is operating efficiently.
What causes the P2032 code?
This code is an indicator of a problem with the catalytic converter system on the later model diesel engines. It is set when the Engine Control Module (ECM) sees a low voltage from the sensor within a five second time frame. The sensor should rapidly fluctuate from high to low voltage.
Possible problems that would set this code are:
Bad EGT sensor (EGT sensors can fail under extreme temperatures produced by extreme operation conditions such as towing a heavy load up a long/steep grade)
Short to voltage in the exhaust temperature circuit
Damaged wiring to the EGT sensor
Catalytic converter is not reaching operating temperature
Cold running engine for an excessive amount of time (there will usually will be other codes set in this case)
Catalytic converter is not warming up fast enough
Catalytic converter has failed
What are the symptoms of the P2032 code?
The catalytic converter system on a modern diesel engine is quite complicated. Because of the complicated programming involved and each manufacturer's design choices when building this system, the symptoms that could follow are random and numerous.
Usually, it will simply be an illuminated Check Engine Light. In some cases, the manufacturer programs a reduced engine output safety mode into the ECM. If this should occur, the vehicle will significantly lack power and the Check Engine Light will be on with several codes present. Other times, malfunctions with this system will cause random drivability problems during different driving conditions.
How does a mechanic diagnose the P2032 code?
EPA (Environmental Protection Agency) emissions requirements for catalytic converter systems on diesel engines have been relatively lax, until stricter regulations were implemented between 2007 and 2010. With the introduction of more complicated catalyst systems, it is vitally important that technicians takes extra time to study the specific system that they are working on.
As usual, connecting a scanner to the vehicle to check and monitor for all codes and appropriate data should be the first step. Each manufacturer has its own programming and design specifications that will dictate the procedures to be followed for the diagnosis of their specific system. In general, the technician will:
Scan the vehicle for all codes
Perform a visual inspection of the catalytic converter system
Disconnect the connector at the affected sensor and check for resistance and or voltage specifications provided by the manufacturer (this will be done for the sensor, wiring to the sensor and the PCM; there will be manufacturer-specific procedures to be followed when doing this)
Run various bidirectional tests with the scanner (these tests are specific to each manufacturer and can only be run with a scanner)
Review freeze frame data
Monitor exhaust gas temperatures on a test drive to duplicate the conditions shown in the freeze frame data (these codes will often occur under specific conditions, such as towing a heavy load up a steep grade)
Remove the EGT sensor and check for contamination
Common mistakes when diagnosing the P2032 code
These systems can be very difficult to diagnose. For this reason, many shops simply won’t work on diesel engines. The emissions systems for diesels are different from gas engines. Diesel engines are not as common as gas powered vehicles and many shops are not motivated to work on diesels due to their relative rarity in comparison to gas powered vehicles.
How serious is the P2032 code?
Relatively speaking, this code is not serious. It isn’t an indication of something bad that will happen to the vehicle if it isn’t repaired. It really depends on the importance we place on protecting the environment. Other than the choice of the manufacturer to reduce power output when these systems fail, the environment is the only thing to lose when a catalyst system isn’t working up to par.
What repairs can fix the P2032 code?
- Replace EGT sensor
- Repair damaged wiring to the EGT sensor
- Replace the ECM
- Replace the catalytic converter
- Reprogram the ECM
- Perform a Diesel Particulate Filter Regeneration procedure with a scanner
Additional comments for consideration regarding the P2032 code
Only manufacturers that produce diesel vehicles past the 2007 model year will use this code. Diesel engines are not as common as gas vehicles in the American market. Because of their relative rarity, most shops will not take on a diagnosis of the emission systems for a diesel engine. There are specialty repair shops that work almost exclusively on diesel vehicles.
In addition, the emission systems on a diesel vehicle is more complicated than a gas vehicle. The catalytic converter manufacturing requirements is considerably more stringent in order to meet the EPA standards, in which most are applied to the 2007 through 2010 models years. As many as six sensors, three DEF (Diesel Exhaust Fluid) nozzles, a diesel light off nozzle, and a delivery system for DEF is often involved. All of these components add up to more complications and more for the technician to learn in order to effectively diagnose and repair these systems.
A diesel exhaust system has three stages and four separate systems to warm, maintain, and enable it to reduce both HC’s (hydrocarbons) and NOx (oxides of nitrogen). This happens in three stages: DOC (diesel oxidation catalyst) stage, SCR (selective catalyst reduction) stage and the DPF (diesel particulate filter) stage. Each stage requires its own systems, which allows it to operate at optimum efficiency.
Not only are there three stages of emissions reduction, but each stage has its own unique needs to operate at peak efficiency, if not at all. The DOC stages requires an injection of diesel fuel to maintain temperature. The SCR stage is used to reduce NOx and requires the injection of DEF to operate. The DPF stage removes what is left of any particulate material in the exhaust. This final stage requires the PCM to run what is known as a DPF regeneration.
There are two different injection systems. The DEF and the diesel injection system. There is a temperature system monitoring the entire system in up to six locations. There is a direct monitoring of NOx and O2 to determine if the converter system is actually reducing emissions. The three stages and the four systems maintaining them must all work in concert for which the PCM is the conductor.
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