Engine Controls - New DTC's

SOURCE: Kia Technician Times

TITLE: New DTC's

APPLIES TO: Sportage

SERVICE TIP:

From 10/01/00 production, two more diagnostic routines have been added to the Sportage OBDII system:
Thermostat Monitoring and Intake Air Temperature (IAT) rationality check.

Thermostat Monitoring effectively ensures that a defective thermostat, which may go unnoticed by the customer, is detected by the engine management system. (Note that it had already been introduced in other Kia models, and currently covers all US vehicles.)

Thermostat Monitoring typically compares coolant temperature behavior after start-up (cold) to either an expected value or behavior. In the case of Sportage, if a drop of at least 4 degrees F (indicating the thermostat has opened) is not detected during two consecutive drive cycles/warm-ups, the ECM will store a DTC P0128.

The Intake Air Temperature rationality check monitors the sensor's circuit as well as informs the ECM whether the signal matches the expected value or range for the circumstances. For example, if the IAT signal reads extremely high or low, the ECM would conclude that the signal is incorrect and would store a DTC P0111. The ECM can also determine a faulty sensor by comparing the IAT sensor signal to changes in coolant temperature over a certain period of time.