P2609 OBD-II Trouble Code: Intake Air Heater System Performance

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P2609 code definition

A P2609 trouble code indicates that the PCM has detected abnormal voltage readings from one or more of the intake air heater circuits. This particular trouble code is most often associated with trouble codes P2604, P2605, P2606, P2607, and P2608.

What the P2609 code means

A P2609 OBD-II trouble code means that the variation in the voltage to one or more of the intake air heater circuits has exceeded the manufacturer's stipulated levels. The resulting stored code results in an illuminated Check Engine light, though some models of vehicles might require multiple drive cycles, at least three, before the Service Engine Soon Light will illuminate.

What causes the P2609 code?

The most common cause of a P2609 trouble code is a faulty intake air heater relay. Some other causes of this trouble code include:

  • Shorted or open connectors or wiring.
  • A burnt out heater element.
  • A bad intake air heater blower.
  • A faulty, or disconnected, intake air temperature sensor.
  • A faulty PCM, though this is rare.

What are the symptoms of the P2609 code?

Symptoms of a P2609 OBD-II trouble code include:

  • A code stored to the PCM.
  • An illuminated Check Engine light.

How does a mechanic diagnose the P2609 code?

In order to properly diagnose a P2609 trouble code, a mechanic needs an advanced scanner or code reader, a digital volt/ohmmeter, and an infrared thermometer with a laser pointer. To successfully diagnose a P2609 trouble code, a mechanic should take the following steps:

  • Visually inspect all wiring and connectors in the intake air heater system.

  • Replace any damaged, shorted, or disconnected wiring and connectors. If any of the components appear to be damaged, replace those as well.

  • Retest the system after repairing or replacing any wiring, connectors, or components. A mechanic can do this by connecting the advanced scanner to the diagnostic connector and recording all stored codes.

  • To diagnose a component such as the heater blower of heating element, crank the cold engine with the advanced scanner attached.

  • Watch to see if the scanner data shows that the intake air heater is given a command of On by the PCM.

  • If On, can you hear the blower operating?

  • Once you are sure that the blower is operating, find the heating element to make sure that it is warming properly.

  • Next, check the intake air heater relay with the digital volt/ohmmeter to make sure that the relay is grounded at the electrical connector.

  • If the voltage readings don't comply with the manufacturer's specifications, the mechanic needs to disconnect the PCM and perform further testing using the digital volt/ohmmeter.

Common mistakes when diagnosing the P2609 code

While some mechanics might only attribute a P2609 trouble code to a faulty intake air heater relay, they should keep in mind that this is not the only cause of this particular trouble code. Some other potential causes can include PCM failure, though this is rare. In addition, a short in the wiring or connectors, a burnt out heater element, a faulty or disconnected intake air temperature sensor, or a bad intake air heater blower can all lead to the Check Engine light illuminating and a stored P2609 trouble code.

How serious is the P2609 code?

A P2609 trouble code is usually not very serious unless it is associated with one of the other parts of the intake air heater systems, most specifically a burnt out heater element, faulty PCM, or a bad intake air heater blower. In these instances, in addition to the storage of a relevant trouble code or codes and the illumination of the Check Engine light, the faulty part can also cause the intake air heater system to not function properly. A short in the wiring or connectors can also cause this system not to function as it should, leading to a decrease in fuel efficiency.

What repairs can fix the P2609 code?

To repair and clear a P2609 trouble code, a mechanic must first:

  • Replace any shorted, damaged, or disconnected wiring and connectors.

  • Repair any components that need replacement.

  • Once the components, wiring, and connectors have been replaced, the mechanic needs to clear the trouble codes and perform a test drive to ensure that the problem has been fixed.

Additional comments for consideration regarding the P2609 code

Keep in mind that a P2609 trouble code might not always be stored in the PCM when the problem occurs. A P2609 trouble code might require the vehicle to go through up to three cycles before storing the code in the PCM. Diagnosing such a code is helped by recording all stored codes and freeze frame data using the advanced scanner.

Need help with a P2609 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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