Analog inputs such as Intake Air Temperature (P0112, P0113), Engine Coolant Temperature (P0117, P0118), Cylinder Head Temperature (P1289. P1290), Mass Air Flow (P0102, P0103) and Throttle Position (P0122, P0123, P1120), Fuel Temperature (P0182, P0183), Engine Oil Temperature (P0197, P0198), Fuel Rail Pressure (P0192, P0193) are checked for opens, shorts, or rationality by monitoring the analog -to-digital (A/D) input voltage.
ENGINE COOLANT TEMPERATURE SENSOR CHECK OPERATION
| DTCs |
P0117 (low input), P0118 (high input) |
| Monitor execution |
continuous |
| Monitor Sequence |
None |
| Sensors OK |
not applicable |
| Monitoring Duration |
5 seconds to register a malfunction |
TYPICAL ECT SENSOR CHECK MALFUNCTION THRESHOLDS
| Voltage < 0.244 volts or voltage > 4.96 volts |
The ECT rationality test checks to make sure that ECT is not stuck in a range that causes other OBD to be disabled. If after a long (6 hour) soak, ECT is very high (> 230 °F) and is also much higher than IAT at start, it is assumed that ECT is stuck high. If after a long (6 hour) soak, ECT is stuck midrange between 175 °F (typical thermostat monitor threshold temperature) and 230 °F, it is assumed that ECT is stuck mid range.
ECT SENSOR RATIONALITY CHECK OPERATION
| DTCs |
P0116 (ECT stuck high or midrange) |
| Monitor Execution |
Once per driving cycle |
| Monitor Sequence |
None |
| Sensors OK |
ECT, CHT, IAT |
| Monitoring Duration for stuck high |
On first valid sample after key on (engine does not have to start) |
| Monitoring Duration for stuck midrange |
5 seconds to register a malfunction |
TYPICAL ECT SENSOR RATIONALITY CHECK ENTRY CONDITIONS
| Entry Condition |
Minimum |
Maximum |
| Engine-off time (soak time) |
360 min |
|
| Difference between ECT and IAT (stuck high only) |
|
50 deg |
| Engine Coolant Temperature for stuck high condition |
230 °F |
|
| Engine Coolant Temperature for stuck midrange condition |
175 °F |
230 °F |
TYPICAL ECT SENSOR RATIONALITY CHECK MALFUNCTION THRESHOLDS
| ECT stuck high after first valid sample OR ECT stuck midrange for > 5 seconds |
Currently, vehicles use either an ECT sensor or CHT sensor, not both. The CHT sensor measures cylinder head metal temperature as opposed to engine coolant temperature. At lower temperatures, CHT temperature is equivalent to ECT temperature. At higher temperatures, ECT reaches a maximum temperature (dictated by coolant composition and pressure) whereas CHT continues to indicate cylinder head metal temperature. If there is a loss of coolant or air in the cooling system, the CHT sensor will still provides an accurate measure of cylinder head metal temperature. If a vehicle uses a CHT sensor, the PCM software calculates both CHT and ECT values for use by the PCM control and OBD systems.
CYLINDER HEAD TEMPERATURE SENSOR CHECK OPERATION
| DTCs |
P1289 (high input), P1290 (low input), P1299 (fail-safe cooling activated) |
| Monitor Execution |
Continuous |
| Monitor Sequence |
None |
| Sensors OK |
Not applicable |
| Monitoring Duration |
5 seconds to register a malfunction |
TYPICAL CHT SENSOR CHECK MALFUNCTION THRESHOLDS
Voltage < 0.244 volts or voltage > 4.96 volts
For P1299, MIL illuminates immediately if CHT > 270°. Fuel shut-off is activated to reduce engine and coolant temperature |
Beginning in the 2013 MY, an Exhaust Metal Temperature (EMT) sensor has been added to the 2.0L GTDI engine in some vehicles along with an ECT sensor. This EMT sensor is located in the cylinder head near the exhaust port. The signal correlates well to ECT during normal operating conditions with a properly filled and sealed coolant system. However, if the engine coolant system was damaged and coolant was low or lost, the EMT sensor will still sense the actual exhaust metal temperature while the ECT could be sitting in air instead of coolant (reading a much lower temperature). This sensor is used strictly for engine component protection via the PCM's "fail-safe" cooling algorithm with diagnostics for open and short circuit faults (P1289, P1290) along with the "fail-safe" cooling fault (P1299). This EMT sensor is actually a CHT sensor that only uses the high range resistor network, hence it uses the CHT "Hot End" transfer function shown below.
CYLINDER HEAD TEMPERATURE SENSOR CHECK OPERATION
| DTCs |
P1289 (high input), P1290 (low input), P1299 (fail-safe cooling activated) |
| Monitor Execution |
Continuous |
| Monitor Sequence |
None |
| Sensors OK |
Not Applicable |
| Monitoring Duration |
5 seconds to register a malfunction |
TYPICAL CHT SENSOR CHECK MALFUNCTION THRESHOLDS
Voltage < 0.244 volts or voltage > 4.96 volts
For P1299, MIL illuminates immediately if CHT > 270°. Fuel shut-off is activated to reduce engine and coolant temperature |
INTAKE AIR TEMPERATURE SENSOR CHECK OPERATION
| DTCs |
P0112 (low input), P0113 (high input) |
| Monitor Execution |
Continuous |
| Monitor Sequence |
None |
| Sensors OK |
Not Applicable |
| Monitoring Duration |
5 seconds to register a malfunction |
TYPICAL IAT SENSOR CHECK MALFUNCTION THRESHOLDS
| Voltage < 0.244 volts or voltage > 4.96 volts |
ENGINE OIL TEMPERATURE SENSOR CHECK OPERATION
| DTCs |
P0197 (low input), P0198 (high input) |
| Monitor Execution |
Continuous |
| Monitor Sequence |
None |
| Sensors OK |
Not Applicable |
| Monitoring Duration |
5 seconds to register malfunction |
TYPICAL EOT SENSOR CHECK MALFUNCTION THRESHOLDS
| Voltage < 0.20 volts or voltage > 4.96 volts |