P1514

DTC P1514 Throttle Body Performance

Circuit Description

The powertrain control module (PCM) uses TP, BARO, IAT and engine RPM to calculate an expected mass airflow (MAF) rate. The PCM compares this value to the Mass Airflow value and the speed density calculation to verify proper throttle operation.

Conditions For Running the DTC

* DTCs P1515, P1516, P1517, P1518 not set
* DTCs P1120, P1220 and P1221 not set at the same time or DTCs P1120 and P1220 not set at the same time
* Engine operating longer than 1 second
* Engine speed more than 500 RPM

Conditions for Setting the DTC

* The PCM detects that actual MAF and Speed Density is much greater than the expected (calculated) airflow rate
* Above condition met for less than 1 second

Action Taken When the DTC Sets

* The PCM will illuminate the malfunction indicator lamp (MIL) and the Reduced Engine Power light will be on when this diagnostic fails.
* The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.
* If no other TAC System DTCs are set, the TAC System will operate in Reduced Engine Power Mode, and this DTC will be stored. If certain TAC System DTCs are set at the same time, the TAC System will either default to a more tightly restricted mode of operation if it is determined that limited safe operation is possible, or command engine shut down.

Conditions for Clearing the MIL/DTC

* The PCM will turn the MIL OFF after 3 consecutive drive trips that the diagnostic runs and does not fail
* 40 consecutive warm-up cycles have occurred
A History DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* A last test failed (Current DTC) will clear when the diagnostic runs and does not fail
* PCM battery voltage is interrupted

Important: The clear DTC info function may have to be performed twice in order to clear a Throttle Actuator Control System DTC.


* Using a scan tool

Diagnostic Aids

* Inspect the throttle blade for being broken, bent or missing
* Inspect the TP sensor for proper installation
A sensor that is mis-aligned will set this DTC.
* Refer to Intermittents under service category Symptoms Symptoms.
* If a repair is completed and the DTC was cleared using a scan tool on the same ignition cycle, the default action will not clear until an ignition cycle has occurred.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
3. Physically and visually inspect the throttle body assembly and correct any problems that you observe. Manually move the throttle blade from closed to wide open throttle (WOT). You should not need to use excessive force. The throttle blade should move smoothly through the full range and should return to a slightly open position on its own.
5. When the TAC module detects a problem within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info.