DTC Advanced Diagnostics: P2176
DTC P2176:Throttle Actuator Control System Idle Position Not Learned

General Description

The electronic throttle control system starts a learning routine of throttle valve position to correlate the measured value of the throttle position (TP) sensors to the mechanical throttle valve position. The electronic throttle control system uses default values for the lower mechanical stop initially, and then it learns the actual value each time the throttle body is used. During the learning routine, the throttle valve steps from the maximum possible value of the lower mechanical stop to the measured value at the actual lower mechanical stop position. If the throttle body lower mechanical limit cannot be learned, the powertrain control module (PCM) detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Once per driving cycle
Sequence
None
Duration
0.5 second or more
DTC Type
One drive cycle, MIL on
 

Enable Conditions
Condition
Minimum
Maximum
Elapsed time after the vehicle is turned to the OFF (LOCK) mode
5 seconds
–
Engine coolant temperature [ECT Sensor 1]
41.5 °F (5.26 °C)
212.8 °F (100.46 °C)
Intake air temperature [IAT Sensor (1)]
41.5 °F (5.26 °C)
289.8 °F (143.26 °C)
Engine speed [Engine Speed]
–
250 rpm
Vehicle speed [Vehicle Speed]
–
0.6 mph (1 km/h)
12 volt battery voltage [Battery]
10.5 V
16.5 V
[ ]: HDS Parameter

Malfunction Threshold
Initial learning of the closed throttle valve position not possible
The initial learning is not performed.
Learning of the closed throttle valve position not possible
Either of the condition occurs:
?
The difference between the actual learned TP sensor A voltage and the previous read TP sensor A voltage at the mechanical stop is -0.07 V or more.
?
The difference between the actual learned TP sensor B voltage and the previous read TP sensor A voltage at the mechanical stop is -0.07 V or more.
Closed throttle valve position exceeds the threshold
Either of the condition occurs:
?
The TP sensor A voltage is more than 0.69 V or less than 0.51 V during sensor offset learning at lower mechanical stop.
?
The TP sensor B voltage is more than 4.49 V or less than 4.31 V during sensor offset learning at lower mechanical stop.

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.
Throttle valve stuck
Throttle actuator MTR1 line failure
Throttle actuator MTR2 line failure
PCM internal failure

Confirmation Procedure
Operating Condition
1.
Turn the vehicle to the OFF (LOCK) mode.
2.
Turn the vehicle to the ON mode.

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.