What is the P007B fault code?
The P007B fault code is a generic powertrain (OBD-II) code that indicates a problem with the Charge Air Cooler Temperature (CACT) Sensor Circuit Range on Bank 1. This code applies to many vehicles equipped with a turbocharger (Ford, Chevy, VW, Audi, Toyota, etc.), but specific diagnostic procedures may vary by make and model.
Role of the Sensor and Turbocharger
The turbocharger forces air into the engine to increase its power. It consists of a turbine, driven by exhaust gases, and a compressor, which draws in air. To cool this compressed air (and thus increase its density), a charge air cooler (or intercooler) is used.
The Charge Air Cooler Temperature (CACT) sensor measures the temperature of the air exiting the intercooler. The PCM (Powertrain Control Module) uses this data, often comparing it to other temperatures (intake air, coolant), to optimize engine operation and assess the cooler’s efficiency.
Note: The CACT is sometimes integrated with the Manifold Absolute Pressure (MAP) sensor.
Symptoms of the P007B Code
The severity of this code is moderate. Symptoms may include:
- Illuminated Check Engine Light
- Poor performance and loss of power
- Reduced fuel economy
- Activation of limp mode
- Inhibited Diesel Particulate Filter (DPF) regeneration
Possible Causes of the P007B Fault
- Faulty CACT sensor
- Wiring issue (short circuit, open circuit, loose connector)
- Clogged or damaged charge air cooler
- Rare PCM failure
How to Diagnose and Repair the P007B Code?
⚠️ Caution: This procedure is general. Always consult the specific diagnostic diagrams from your vehicle’s manufacturer for accurate repair.
1. Visual Inspection
Inspect the sensor, its connector, and associated wiring. Look for signs of corrosion, damage, or loose connections. Also check the physical condition of the charge air cooler and its ducts. If damage is visible, repair it, clear the code, and test.
2. Sensor and Circuit Testing
A. Diagnostic Tool Test: Using a scan tool, monitor the CACT data. Disconnect the sensor connector; the displayed value should drop sharply. Then short the connector pins; the value should then show a very high temperature. This confirms that the circuit and PCM are functioning and points to a faulty sensor.
B. Sensor Resistance Test: With the engine off, disconnect the sensor and measure its resistance (Ohms) between its two pins. Start the engine and observe the value: it should gradually decrease as the engine warms up. If the resistance does not drop or is inconsistent, replace the sensor.
3. Electrical Circuit Verification
A. Reference Voltage (5V): With the ignition on, measure the voltage at the sensor connector’s reference terminal. You should find approximately 5 volts coming from the PCM. If absent, check continuity between the connector pin and the PCM pin to detect a break.
B. Ground (Earth): With the engine off, check continuity between the connector’s ground pin and the PCM’s ground pin, then between the PCM ground and chassis ground. A lack of continuity indicates an open circuit to repair.
4. PCM Verification
If all other checks are good but no 5V voltage is delivered by the PCM, the PCM is likely faulty. However, this cause is rare.
Conclusion and Call to Action
The P007B code is often resolved by replacing the faulty CACT sensor or repairing damaged wiring. If the diagnostic steps exceed your skills, consult a professional mechanic for an accurate diagnosis and guaranteed repair.