Fault code P007F is called “Charge Air Cooler Temperature (CACT) Sensor Bank 1/Bank 2 Correlation” 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 P007F
Stored code P007F means that the Powertrain Control Module (PCM) has detected a mismatch in the correlation signals. A mismatch has been detected between the discharge air temperature sensors for the individual engine blocks.
This error only applies to vehicles equipped with forced air intake systems and multiple intake air sources. Intake air sources include throttle valves. The forced air intake systems themselves have a turbocharger and supercharger configuration.
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 discharge air cooler temperature sensor (CACT) is used to measure the temperature and therefore the density of the air coming from the cooler. This information is sent to the transmission control module (PCM).
The control module compares the incoming information to the intake air temperature to determine the capacity of the charge air cooler.
If the PCM detects voltage signals from the CAT sensors (for the first and second engine blocks) that reflect the difference. The difference must exceed the maximum allowable parameters, then code P007F will be stored and the Malfunction Indicator Light (MIL) may illuminate.
Symptoms of vehicle malfunctions
The main signal that an error P007F has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- Check engine control lamp on the control panel will light up (the code will be recorded in the memory as a malfunction).
- Poor operation and reduction of engine power.
- Increased fuel consumption.
- The emergency operation mode may be activated.
- If a particulate filter is present, its regeneration may be blocked.
Fault P007F 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 P007F can mean that one or more of the following problems have occurred:
- Faulty discharge 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 P007F
Some suggested steps for troubleshooting and fix the error code P007F:
- Connect the OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
- Before proceeding with diagnosis code P007F, clear any other errors that may be present.
- Inspect the electrical wiring related to the charge air cooler temperature sensor (CACT) for shorts, opens, and damage.
- If necessary, repair or replace any wires that are shorted, broken, damaged, or corroded.
- Inspect the sensor connector for looseness and corrosion.
- Test the CACT sensor; if it is defective, replace it.
- Check the discharge air cooler and repair or replace if necessary.
- If problem persists, check and reprogram or replace control module (PCM) if necessary.
Diagnose and repair of problems
You can begin diagnosing fault P007F by visually inspecting the discharge air cooler temperature sensors 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
Use the diagnostic tool to monitor the data from the discharge air cooler temperature sensors. 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 so, 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 correcting any faults found, the problem with error P007F should be resolved.
On which vehicles does this problem occur most frequently
Fault code P007F can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Ford (Focus, Mondeo, Transit)
- Land Rover (Range Rover, Sport)
- Mercedes-Benz
Fault code P007F can sometimes be found with other errors. The most common are the following: P007A, P007B, P007C, P007D, P007E.
