DTC P011B

DTC P011B:  Intake Air Temperature (IAT) Sensor 1 Circuit Range/Performance Problem

General Description 

Courtesy of HONDA, U.S.A., INC.

The powertrain control module (PCM) is equipped with two engine coolant temperature (ECT) sensors and two intake air temperature (IAT) sensors in order to measure engine temperature. The ECT sensor 1 / ECT sensor 2 and the IAT sensor 2 temperatures are nearly the same as the air temperature after sufficient time has passed. Furthermore, the IAT sensor 1 / IAT sensor 2 values equalize after starting the engine since they are located in the same air intake path. When the system is started after the prescribed time stopped, the IAT sensor 2 detects a malfunction comparing the ECT sensor 1 and ECT sensor 2. When the sensors are normal, the PCM detects a malfunction in the IAT sensor 1 and stores a DTC comparing temperatures from the IAT 1 sensor and IAT 2 sensor after starting the engine.

Monitor Execution, Sequence, Duration, DTC Type 

Execution	Once per driving cycle
Sequence	None
Duration	1 second or more*, 10 seconds or less**
DTC Type	Two drive cycles, MIL on

*: After the system is activated

**: After the engine is started

Enable Conditions 

Condition	Minimum	Maximum
Engine off time	6 hours	-

Malfunction Threshold 

A malfunction is detected if the following conditions are present after the engine has stopped and the vehicle condition has been turned to the OFF (LOCK) mode for at least 6 hours before restarting the engine:

Temperature difference between each sensor values		Malfunction judgment
ECT sensor 1 - ECT sensor 2	IAT sensor 2 - ECT sensor 2	ECT sensor 1	IAT sensor 2	ECT sensor 2
Higher than 57 deg.F (32 deg.C)	Higher than 57 deg.F (32 deg.C)	Normal	Normal	Failure
	From -43 deg.F (-24 deg.C) to 57 deg.F (32 deg.C)	Failure	Normal	Normal
	Lower than -43 deg.F (-24 deg.C)	Failure	Failure	Normal
From -43 deg.F (-24 deg.C) to 57 deg.F (32 deg.C)	Higher than 57 deg.F (32 deg.C)	Normal	Failure	Normal
	From -43 deg.F (-24 deg.C) to 57 deg.F (32 deg.C)	Normal	Normal	Normal
	Lower than -43 deg.F (-24 deg.C)	Normal	Failure	Normal
Lower than -43 deg.F (-24 deg.C)	Higher than 57 deg.F (32 deg.C)	Failure	Failure	Normal
	From -43 deg.F (-24 deg.C) to 57 deg.F (32 deg.C)	Failure	Normal	Normal
	Lower than -43 deg.F (-24 deg.C)	Normal	Normal	Failure

• When the IAT sensor 2 is normal 10 seconds after starting the engine, the IAT 2 sensor is used to detect malfunction in the IAT sensor 1.

Temperature difference between each sensor values	Malfunction judgment
IAT sensor 1- IAT sensor 2	ECT sensor 1
Higher than 57 deg.F (32 deg.C)	Failure
From -43 deg.F (-24 deg.C) to 57 deg.F (32 deg.C)	Normal
Lower than -43 deg.F (-24 deg.C)	Failure

Possible Cause 

Confirmation Procedure 

Operating Condition 

1. Turn the vehicle to the OFF (LOCK) mode, and wait at least 6 hours.
2. Enter the maintenance mode, than start the engine, and let it idle for at least 10 seconds.

• Do not use an engine block heater because the engine coolant temperature will not stay equal during engine stop.
• When freeze data is stored, test the vehicle under an ambient temperature close to the intake air temperature in the freeze data.

With the HDS 

None.

Diagnosis Details 

Conditions for setting the DTC 

When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC 

The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.