• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
TAC Motor Control High | P2102 | P2102, P2119* | P2103 | P2102 |
TAC Motor Control Low | P2103 | P2102, P2119* | -- | -- |
*P2119 set when resistance in the circuit was less than 15 ohms |
The throttle valve in the throttle body utilizes a throttle return spring to assist in positioning the throttle valve at a resting or default position. The powertrain control module (PCM) uses driver input from the accelerator pedal position (APP) sensor in order to calculate the desired throttle position. The PCM sends the desired throttle position or target value to the throttle actuator control (TAC) module. The TAC module achieves the desired throttle position by commanding the throttle control motor to position the throttle valve at the target value. The TAC module then compares the throttle position (TP) sensor 1 value to the target value. If necessary, the throttle control motor is moved slightly in order to obtain the exact target value position.
• | The power supply to the TAC motor is more than 8 volts. |
• | The DTCs run continuously once the above condition has been met. |
When the duty cycle of the open command for the TAC motor is more than 80 percent, the TAC motor current is less than 0.5 amp.
• | The TAC motor current is more than 7 amps for 600 milliseconds. |
OR |
• | The TAC motor current is more than 10 amps for 100 milliseconds. |
• | DTC P2102 and P2103 are Type A DTCs. |
• | The PCM enters the Fail-Safe function operating in the Reduced Engine Power Mode. The throttle valve return spring will close the throttle valve to the idle position with the TP sensor 1 angle defaulted to 19 percent. |
DTC P2102 and P2103 are Type A DTCs.
• | TAC Motor Current is displayed on the scan tool, but the displayed value freezes when the MIL illuminates and the DTC sets. |
• | DTC P2103 can set from a momentary current surge that occurs when the TAC system ignition 1 voltage supply to the PCM is interrupted. Diagnose this failure using the procedure in DTC P2118. Refer to DTC P2118. |
• | Engine acceleration will be compromised and AT downshifts delayed when operating in the Fail-safe mode. |
Throttle Actuator Control (TAC) System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If DTC P2118 is set, refer to DTC P2118. |
Important:
• The TAC system DTCs must be cleared before testing for voltage. The PCM will not provide voltage to the TAC motor circuits when a TAC or TP sensor DTC is set. • The engine cannot be running when testing for voltage. If the engine is started, a TAC system DTC will set and the PCM will not provide voltage to the TAC motor circuits. • Do not disconnect the TAC module harness connector unless instructed to do so. A TP sensor DTC will set when the ignition is turned ON.
Important: With the TAC module disconnected, a TP sensor DTC will set and the PCM will not provide voltage to the TAC motor circuits.
⇒ | If greater than the specified range, test the TAC motor control circuit for a short voltage. If the circuit tests normal, replace the PCM. |
• | TP sensor 1 signal circuit terminal 6 |
• | TP sensor 2 signal circuit terminal 4 |
• | TP sensor 5-volt reference circuit terminal 5 |
• | TP sensor ground circuit terminal 3 |
• | TAC motor control low circuit terminal 1 |
• | TAC motor control high circuit terminal 2 |
⇒ | If less than the specified range, test the TAC motor control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for control module replacement, setup, and programming |