P2030 – Auxiliary he·ater (fuel fired) – performance problem


By Reinier (Contact Me)
Last Updated 2018-01-05
Automobile Repair Shop Owner

Trouble CodeFault LocationProbable Cause
P2030 Auxiliary he·ater (fuel fired) - performance problem Auxiliary heater system

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What Does Code P2030 Mean?

OBD II fault code P2030 is a generic code that is defined as “Auxiliary heater (fuel fired) – performance problem”, and is set when the PCM (Powertrain Control Module) detects one or more problems with the auxiliary heater that relate to the general performance of the fuel –fired auxiliary heating system. Note that code P2030 is very often caused by manufacturer specific codes and issues that cause the heating system to either produce too little, or too much heat.

NOTE #1: Auxiliary heater performance issues are typically linked with manufacturer specific problems in the climate control system and/or the body control module, and generally mean that the heating system either does not work for long enough, or that it does not deactivate after the time the manufacturer has set for it work, has elapsed.

NOTE #2: While auxiliary heating systems, and especially fuel-fired systems, are rare to almost non-existent on American-produced vehicles, these systems are very common on diesel-powered vehicles that are produced in Europe, with the most notable examples being VAG group vehicles, as well as Volvo, Saab, and Opel/Vauxhall models.

While the design specifics of fuel-fired auxiliary heating systems vary between manufacturers, all systems have the purpose of producing heat to warm mainly the passenger cabin. Since diesel engines are much more efficient than gasoline engines, a diesel engine takes significantly longer than a gasoline engine to heat up to the point where the engine coolant is sufficiently hot to supply heat to the cabin via the conventional heating system. Thus, in practice, an auxiliary heating system can produce heat within a few seconds of starting the engine, and will usually produce heat for a maximum period of about 30 minutes or so on most applications.

In terms of operation, a fuel-fired auxiliary heating system burns a small amount of fuel in a sealed combustion chamber. The resulting hot air is then distributed by a blower or fan to various parts of the vehicle via the existing heating/ventilation ducting network. However, due to high risk of harmful diesel combustion products reaching the inside of the vehicle, the PCM uses input data from sensors that monitor the atmosphere inside the vehicle for the presence of harmful and toxic gasses. Failure of these sensors is very common, and one or the primary causes of the PCM disabling the system for safety reasons.

Nonetheless, some manufacturers also use the fuel-fired auxiliary heating system to heat the engine coolant for a preset time before the engine is started, while others use the system to heat the engine block as well. The practical advantages of this that a warm engine is easier to start on the one hand, and that a warm engine distributes engine oil more efficiently, thus reducing mechanical wear of moving parts during engine starts in sub-zero temperatures, on the other hand.

Other components of the auxiliary heating system include electrical wiring, connectors, timers and fuses, a thermostat, small-diameter fuel lines, a dedicated fuel filter, an injector to vaporize the fuel, an electrical igniter to ignite the fuel when the system is activated, a fan or blower, various pressure sensors, and a system through which the heating system’s exhaust gasses can be extracted safely to the main exhaust system.

From the above it should be obvious that the entire fuel-fired auxiliary heating system must be in perfect working order for it not to pose a safety or health risk to the vehicles’ occupants. Therefore, the PCM monitors all the components and circuits that control the auxiliary heating system on a continuous basis, and should it detect that any part, component, system, circuit, or subsystem within the auxiliary heating system is operating outside of acceptable parameters in any way, it will set code P2030, and illuminate a warning light as a result. Note that in extreme cases, the PCM may disable the entire auxiliary system as a safety precaution until the problem is resolved.

Where is the P2030 sensor located?

The image above shows the typical construction and layout of a fuel-fired auxiliary hearting unit. In this image, the yellow arrow indicates the fan that forced heated air into the ducting system, the green arrow indicates the electrical wire/igniter that ignites the fuel; the black arrow indicates the fuel feed line, the red arrow indicates the sealed-off combustion chamber, and the blue arrow indicates the exit through which heated air leaves the unit. The blue area surrounding the combustion chamber represents the area in which atmospheric air that is in contact with the outside of the combustion chamber is being heated.

Note that depending on the application, the auxiliary heating unit can be located in a number of places on the vehicle. On some applications, the unit is located in the engine compartment, while on others it can be located at a variety of places under the vehicle, or even in a front wheel well. Therefore, it is important always to refer to the manual for the affected application to identify and locate all parts, components, wiring, fuel lines, and control switches correctly. Failure to refer to the manual could result in a misdiagnosis, wasted time, and the distinct possibility that further damage to the auxiliary heating system might occur.

What are the common causes of code P2030?

Note that since auxiliary heater performance issues can sometimes be caused by failures and malfunctions in the climate-, and body control systems, all additional codes must be resolved in the order in which they were stored before a diagnostic procedure for code P2030 is attempted. Failure to do this will almost certainly result in wasted time, confusion, one or more misdiagnoses, and the distinct possibility that further damage to the vehicle’s electrical system could occur.

Nonetheless, some common causes of code P2030 could include the following-

  • Failure of one or more sensors that monitor the quality of the passenger cabin air
  • Damaged, shorted, disconnected, or corroded wiring and/or connectors
  • Failure of the climate control system’s thermostat
  • Defective auxiliary heating system timer(s)
  • Abnormal voltages in any part of the heating system’s control circuit
  • Failure of the blower/fan motor
  • Failure of the fuel igniter
  • Defects and/or malfunctions in the fuel feed system
  • Failed or failing PCM, climate control module, and/or body control module. Note that this is a rare event, and the fault must therefore be sought elsewhere before any control module is replaced

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