P011D Charge / Intake Air Temperature Correlation, Bank 2

P011D Charge / Intake Air Temperature Correlation, Bank 2

OBD-II DTC Datasheet

Correlation Between Charge Air Temperature and Intake Air Temperature, Bank 2

What does this mean?

This Generic Powertrain Diagnostic Trouble Code (DTC) typically applies to all OBD-II vehicles. This may include, but is not limited to, Nissan, Toyota, Chevrolet, GMC, Ford, Dodge, Vauxhall, etc. Despite the general nature, the exact repair steps may vary depending on the brand / model.

A stored code P011D means the powertrain control module (PCM) has detected a mismatch in the correlation signals between the charge air temperature (CAT) sensor and the intake air temperature (IAT) sensor for engine block two.

Bank 2 refers to an engine group that does not contain number one cylinders. As you can probably tell from the description of the code, this code is only used in vehicles that are equipped with forced air devices and multiple air intake sources. The intake air sources are called butterfly valves. Forced air units include turbochargers and blowers.

CAT sensors usually consist of a thermistor that protrudes from the housing on a wire stand. The resistor is positioned so that ambient air entering the engine inlet can pass through the aftercooler (sometimes called the charge air cooler) after exiting the intercooler. The housing is usually designed to be threaded or bolted to the turbocharger / supercharger inlet pipe next to the intercooler). As the charge air temperature rises, the resistance level in the CAT resistor decreases; causing the circuit voltage to approach the reference maximum. The PCM sees these changes in the CAT sensor voltage as changes in the charge air temperature.

The CAT sensor (s) provide data to the PCM for boost pressure solenoid and boost valve operation, as well as certain aspects of fuel delivery and ignition timing.

The IAT sensor acts in much the same way as the CAT sensor; In fact, in some early (pre-OBD-II) computerized vehicle manuals, the intake air temperature sensor was described as a charge air temperature sensor. The IAT sensor is positioned so that ambient intake air flows through it as it enters the engine intake. The IAT sensor is located next to the air filter housing or air intake.

A P011D code will be stored and the Malfunction Indicator Lamp (MIL) may illuminate if the PCM detects voltage signals from the CAT sensor and IAT sensor that differ by more than a preprogrammed degree. It may take multiple ignition failures to illuminate the MIL.

What is the severity of this DTC?

Overall engine performance and fuel economy can be adversely affected by conditions that contribute to the persistence of a P011D code and should be considered Severe.

What are some of the symptoms of the code?

Symptoms of a P011D trouble code may include:

• Reduced engine power
• Excessively rich or lean exhaust
• Delay in starting the engine (especially cold)
• Reduced fuel efficiency

What are some of the common causes for the code?

Reasons for this code may include:

• Faulty CAT / IAT sensor
• Open or short circuit in the wiring or connector of the CAT / IAT sensor
• Limited intercooler
• PCM or PCM programming error

What are some of the steps in the P011D diagnosis?

I would have access to a diagnostic scanner, digital volt / ohmmeter (DVOM) and reliable vehicle information source before attempting to diagnose the P011D code.

Diagnosing any code associated with a CAT sensor should begin by checking that there are no obstructions to air flow through the intercooler.

A visual inspection of all CAT / IAT system wiring and connectors is OK as long as there is no obstruction to the intercooler and the air filter is relatively clean. Repair if necessary.

Then I connected the scanner to the car diagnostic port and got all stored codes and freeze frame data. Freeze frame data can best be described as a snapshot of the exact circumstances that occurred during the fault that led to the stored code P011D. I like to write this information down because it can be helpful in diagnostics.

Now clear the codes and test drive the vehicle to make sure the code is cleared.

If this:

• Check individual CAT / IAT sensors using DVOM and your vehicle information source.
• Place the DVOM on the Ohm setting and test the sensors by unplugging them.
• Consult your vehicle information source for component testing specifications.
• CAT / IAT sensors that do not meet manufacturer's specifications must be replaced.

If all sensors meet manufacturer's specifications:

• Check the reference voltage (typically 5V) and ground at the sensor connectors.
• Use the DVOM and connect the positive test lead to the reference voltage pin of the sensor connector with the negative test lead connected to the ground pin of the connector.

If you find the reference voltage and ground:

• Connect the sensor and check the sensor signal circuit with the engine running.
• To determine if the sensor is working properly, follow the temperature and voltage diagram found in the vehicle information source.
• Sensors that do not reflect the same voltage (depending on intake / charge air temperature) specified by the manufacturer must be replaced.

If the sensor signal circuit reflects the correct voltage level:

• Check the signal circuit (for the sensor in question) at the PCM connector. If there is a sensor signal at the sensor connector but not at the PCM connector, there is an open circuit between the two components.
• Test individual system circuits with DVOM. Disconnect the PCM (and all associated controllers) and follow the diagnostic flowchart or connector pinouts to test the resistance and / or continuity of an individual circuit.

If all CAT / IAT sensors and circuits are within specifications, suspect a PCM failure or PCM programming error.

• Review Technical Service Bulletins (TSBs) for assistance with diagnosis.
• The IAT sensor often remains disabled after replacing the air filter or other related maintenance.

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