Powertrain Controls Diagnosis

CIRCUIT DESCRIPTION
The throttle position (TP) sensor 2 is a potentiometer type sensor with three circuits:
- A 5-volt reference circuit
- A low reference circuit
- A signal circuit

The TP sensor is used to determine the throttle plate angle for various engine management systems. The PCM provides the TP sensor a 5-volt reference circuit and a low reference circuit. The TP sensor then provides the PCM a signal voltage proportional to throttle plate movement. TP sensor 1 signal voltage is low at closed throttle and increases as the throttle opens. When the PCM detects that the TP sensor 2 signal or TP sensor 5-volt reference voltage is outside the predetermined range, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
- DTCs P1518 or P2108 are not set.
- The ignition switch is in the crank or run position.
- The ignition voltage is more than 5.23 volts.

CONDITIONS FOR SETTING THE DTC
- The TP sensor 2 voltage is less than 0.28 volt or greater than 4.60 volts.
- The above condition is present for more than 1 second.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or the Failure Records.
- The PCM commands the TAC system to operate in the Reduced Engine Power mode.

OR

- Under certain conditions the PCM commands the engine OFF.
- The message center displays Reduced Engine Power.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM 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.
- Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
- Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
- When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
- If this DTC is determined to be intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-3:

Steps 4-5:

Steps 6-9:

Steps 10-14:

Steps 15-18:

Steps 19-22:

Steps 23-26:

Steps 27-31:

The number below refers to the step number on the diagnostic table.
31. When the TAC module detects a condition 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 condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture Info.