Fault code P00A3 – charge air cooler temperature sensor circuit high (Bank 2)

Fault code P00A3 is called “Charge Air Cooler Temperature (CACT) Sensor Circuit High (Bank 2)” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P00A3

The diagnosis code P00A3 is a general diagnosis code that applies to vehicles that have a charge air cooler temperature sensor. Although generic, the exact repair steps may differ depending on the make as well as the model.

Fault code P00A3 – charge air cooler temperature sensor circuit high (Bank 2)

A turbocharger is an air pump used to force air into the engine. It consists of two connected parts, a turbine and a compressor.

The turbine is attached to the exhaust manifold, where it is driven by the exhaust gases. The compressor is attached to the air intake. Both are connected by a shaft, so when the turbine spins, the compressor also spins, allowing the intake air to be drawn into the engine.

Many engines are equipped with a discharge air cooler, also known as an intercooler. Charge air coolers can be air-liquid or air-air, but they are all designed to cool the air entering the intake.

The charge air cooler temperature sensor (CACT) is used to measure the temperature and therefore the density of the air coming out of the cooler. This information is sent to the powertrain control module (PCM).

The control module compares the incoming information to the intake air temperature to determine the capacity of the charge air cooler.

Code P00A3 is set when the PCM detects a high signal level in the discharge air cooler temperature sensor circuit (Bank 2). In multi-unit engines, Bank 2 refers to a cylinder group that does not include cylinder 1.

Symptoms of vehicle malfunctions

The main signal that an error P00A3 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. Check engine control lamp on the control panel will light up (the code will be recorded in the memory as a malfunction).
  2. Poor operation and reduction of engine power.
  3. Increased fuel consumption.
  4. The emergency operation mode may be activated.
  5. If a particulate filter is present, its regeneration may be blocked.

Fault P00A3 is considered serious, as it affects the safety and drivability of the vehicle. Ignoring the fault may result in costly repairs, it is recommended to eliminate the problem as soon as possible.

Factors that can cause this error code

The error code P00A3 can mean that one or more of the following problems have occurred:

  • Faulty charge air cooler temperature sensor (CACT).
  • Open circuit in the sensor signal circuit (CACT).
  • Corrosion or damage to electrical connector.
  • Ground fault or voltage short circuit.
  • Faulty discharge air cooler.
  • Sometimes faulty PCM is the cause.

How to fix or reset OBD-2 code P00A3

Some suggested steps for troubleshooting and fix the error code P00A3:

  1. Connect the OBD-II scan tool to the vehicle’s diagnostic connector and read all stored data and error codes.
  2. Before proceeding with diagnosis code P00A3, clear any other errors present.
  3. Check the electrical wiring related to the charge air cooler temperature sensor (CACT) for shorts, opens, and damage.
  4. If necessary, repair or replace any wires that are shorted, broken, damaged, or corroded.
  5. Inspect the sensor connector for looseness and corrosion.
  6. Test the CACT sensor; if it is defective, replace it.
  7. Check the discharge air cooler and repair or replace if necessary.
  8. If problem persists, check and reprogram or replace control module (PCM) if necessary.

Diagnose and repair of problems

You can begin diagnosing error P00A3 by visually inspecting the discharge air cooler temperature sensor and associated wiring. Look for loose connections and damaged wiring.

Also visually inspect the discharge air cooler and ducts. If damage is found, repair, then clear the code and see if it returns.

Testing the circuit

Using a diagnostic tool, monitor the data parameters from the discharge air cooler temperature sensor. Disconnect the CACT sensor, the value on the diagnostic tool should drop to a very low value.

Then connect a jumper to the terminals, the diagnostic tool should show a very high temperature. If it does, then the problem is with the sensor and not with the circuit or PCM module.

Check sensor

Disconnect the discharge air cooler temperature sensor connector. Then measure the resistance between the two sensor leads with a digital multimeter set to ohms.

Start the engine and look at the values, they should decrease smoothly as the engine warms up. Check the engine temperature gauge on the dashboard to make sure the engine has reached operating temperature.

If the engine temperature increases but the CACT resistance does not decrease, the sensor is defective and must be replaced. After troubleshooting, the problem with error P00A3 should be resolved.

On which vehicles does this problem occur most frequently

Fault code P00A3 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Audi
  • Chevrolet
  • Ford
  • Land Rover
  • Mitsubishi
  • Nissan (Patrol)
  • Toyota
  • Volkswagen

Fault code P00A3 can sometimes be found with other errors. The most common are the following: P00A0, P00A1, P00A2, P00A4.


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