Technical Description of OBD-II Trouble Code
Intermittent/Erratic Circuit for Charge Air Cooler Temperature Sensor in Bank 2
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to OBD-II equipped vehicles with a charge air cooler temperature sensor (Chevy, Ford, Toyota, Mitsubishi, Audi, VW, etc.). While it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
A turbocharger functions as an air pump that forcefully introduces air into the engine. It consists of two sections: the turbine and the compressor.
The turbine is connected to the exhaust manifold and is driven by exhaust gases. The compressor is attached to the air intake. Both sections are linked by a shaft, so when the turbine spins, the compressor also spins, allowing intake air to be drawn into the engine. Cooler air results in a denser intake charge, leading to increased power. For this reason, many engines are equipped with a charge air cooler, also known as an intercooler. Charge air coolers can be either air-to-liquid or air-to-air coolers, but their purpose remains the same – to cool the air entering the intake.
A charge air cooler temperature sensor (CACT) is used to measure the temperature and density of the air entering or exiting the charge air cooler. This information is sent to the powertrain control module (PCM), where it is compared to the intake air temperature (and sometimes the engine coolant temperature and exhaust gas recirculation temperature) to assess the performance of the charge air cooler. The PCM sends a reference voltage (typically 5 volts) through an internal resistor and measures the voltage to determine the charge air cooler temperature.
Note: In some cases, the CACT is integrated into the boost pressure sensor.
Code P00A4 is triggered when the PCM detects an intermittent issue with the signal from the charge air cooler temperature sensor. The mention of “Bank 2” indicates that the problem lies in the second bank of the engine, which does not include cylinder #1.
Other diagnostic codes related to the charge air cooler temperature sensor circuit in bank 2 include:
Code Severity & Symptoms
These codes have a moderate severity level.
Symptoms of a P00A4 engine code may include:
Causes
Possible causes for the P00A4 code include:
Diagnostic and Repair Procedures
Begin by visually inspecting the charge air cooler temperature sensor and the corresponding wiring. Look for loose connections, damaged wiring, etc. Also, visually inspect the charge air cooler and ducting. If any damage is found, repair it as necessary, clear the code, and check if it reappears.
Next, check for any technical service bulletins (TSBs) related to the issue. If no relevant information is found, proceed with step-by-step diagnosis of the system.
The following is a general procedure, as the testing process for this code varies between vehicles. To accurately test the system, refer to the manufacturer’s diagnostic flow chart.
Check the circuit
