Powertrain Controls - ECM/PCM

Diagnostic Chart.:

Circuit Schematic:

TP SENSOR CIRCUIT-VOLTAGE OUT OF RANGE HIGH
The throttle position (TP) sensor is a variable resistor that is connected to a five volt reference source, a ground, and an input signal at the PCM. When the throttle blade is closed, the sensor input voltage will be low and increase as the throttle is opened. The TP sensor is mounted on the throttle body and connected to the throttle shaft which is controlled by accelerator movement.

DTC PARAMETERS

DTC 21 will set if:
^ The PCM sees TP sensor voltage over 4.9 volts.

DIAGNOSTIC AIDS
When attempting to diagnose an intermittent problem, use the Scan tool[1] to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem.

Intermittents or opens suspected to be at the connector can be detected by using Diagnostic Service Probe. Voltage can be read on wires without disconnecting any connectors.

Check the tightness of the female terminal grip with a spare male terminal.

Normal voltage readings should vary smoothly from 0.4 volts to 4.7 volts ± 0.2 volts as the throttle is moved from closed to wide open position.

[1]Select Malfunction History from Scan tool Engine Control (EC) menu