P1221

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor is mounted on the throttle body of the Throttle Actuator Control (TAC) assembly. The sensor is actually 2 individual throttle position sensors within 1 housing. Two separate signal circuits, a low reference circuit and a 5-volt reference circuit, are used in order to connect the TP sensor assembly and the throttle actuator control module. Each TP sensor signal voltage increases as the throttle opens. The signal circuit for TP sensors are pulled up to 5-volt reference voltage.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0606, P1517,or P1518 are not set.
^ The ignition switch is in the crank or run position.
^ The Electronic Throttle Control (ETC) serial data is operational.

CONDITIONS FOR SETTING THE DTC
TP sensor 1 and TP sensor 2 disagree by more than 0.17 volts.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC "Last Test Failed" clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
When the TAC module detects a condition within the Electronic Throttle Control (ETC) system, the Powertrain Control Module (PCM) receives a message across serial data, and more than 1 ETC system related DTC may set. This condition is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Be aware of this condition when you review the captured DTC info.

If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-4:

Steps 5-18:

The number below refers to the step number on the diagnostic table.
18. When the TAC module detects a condition within the ETC system, the PCM receives a message across serial data. More than 1 ETC system-related DTC may set. This condition is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Be aware of this condition when you review the captured DTC info.