2005 MY OBD System Operation Summary for Gasoline Engines

Currently, vehicles use either an ECT sensor or CHT sensor, not both. The CHT sensor measures cylinder headmetal temperature as opposed to engine coolant temperature. At lower temperatures, CHT temperature isequivalent to ECT temperature. At higher temperatures, ECT reaches a maximum temperature (dictated bycoolant composition and pressure) whereas CHT continues to indicate cylinder head metal temperature. If there isa loss of coolant or air in the cooling system, the CHT sensor will still provides an accurate measure of cylinderhead metal temperature. If a vehicle uses a CHT sensor, the PCM software calculates both CHT and ECT valuesfor use by the PCM control and OBD systems.Cylinder Head Temperature Sensor Check Operation:DTCsMonitor executionMonitor SequenceSensors OKMonitoring DurationP1289 (high input), P1290 (low input), P1299 (fail-safe cooling activated)continuousnonenot applicable5 seconds to register a malfunctionTypical CHT sensor check malfunction thresholds:Voltage < 0.244 volts or voltage > 4.96 voltsFor P1299, MIL illuminates immediately if CHT > 270 o. Fuel shut-off is activated to reduce engine and coolanttemperatureIntake Air Temperature Sensor Check Operation:DTCsMonitor executionMonitor SequenceSensors OKMonitoring DurationP0112 (low input), P0113 (high input)continuousnonenot applicable5 seconds to register a malfunctionTypical IAT sensor check malfunction thresholds:Voltage < 0.244 volts or voltage > 4.96 voltsEngine Oil Temperature Sensor Check Operation:DTCsMonitor executionMonitor SequenceSensors OKMonitoring DurationP0197 (low input), P0198 (high input)continuousnonenot applicable5 seconds to register a malfunctionTypical EOT sensor check malfunction thresholds:Voltage < 0.20 volts or voltage > 4.96 voltsFORD MOTOR COMPANY REVISION DATE: APRIL 28, 2004 PAGE 76 OF 131