DTC P2176

DTC P2176:  Throttle Actuator Control System Idle Position Not Learned

General Description 

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

The electronic throttle control system controls the throttle valve opening. The system includes the throttle actuator, the throttle valve, throttle position (TP) sensors A and B, the electronic throttle control system (ETCS) control relay, the accelerator pedal position (APP) sensor, and the powertrain control module (PCM). When the accelerator pedal is pressed, the APP sensor detects the accelerator pedal opening value. The accelerator pedal opening value is converted to a signal in the APP sensor and transmitted to the PCM to compute the target position. The PCM determines the throttle valve target position according to the signal received and operates the throttle actuator to move the throttle valve to the target position. The actual throttle valve position is determined by TP sensors A and B (installed in the throttle body). The PCM transmits a signal to the throttle actuator and moves the throttle valve to the fully closed position to register the throttle valve fully closed position after the vehicle is turned to the OFF (LOCK) mode. When the registration of the throttle valve fully closed position is not completed within a predetermined time or the registered value is out of predetermined range after the vehicle is turned to the OFF (LOCK) mode, the PCM detects a malfunction in the throttle actuator control system and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status 

Execution	Once per driving cycle
Sequence	None
Duration	2.0 seconds or more
DTC Type	One drive cycle, MIL on
OBD Status	PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Enable Conditions 

Condition	Minimum	Maximum
12 volt battery voltage [BATTERY]	6.0 V	-
Vehicle	OFF (LOCK) mode
No active DTCs set (prevents monitor from running)	P0122, P0123, P0222, P0223, P1659, P2101, P2118, P2135

[ ]: HDS Parameter

Malfunction Threshold 

One of these conditions is met for at least 2.0 seconds:

• The registration of the throttle valve fully closed position is not completed within a predetermined time after the vehicle is turned to the OFF (LOCK) mode.
• The registered value of the throttle valve fully closed position is 0.74 V*, 1.61 V**, or more, or 0.49 V*, 1.37 V**, or less.

* : TP sensor A [TP SENSOR A]

**: TP sensor B [TP SENSOR B]

Possible Cause 

NOTE:  The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

• PCM failure
• Throttle actuator MTR1 line failure
• Throttle actuator MTR2 line failure
• Throttle body failure

Diagnosis Details 

Conditions for setting the DTC 

When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

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.