Charge Air Cooler Monitoring
The 6.7L engine is equipped with an air to water charge air intercooler. The CAC is on a secondary coolant loop, independent from the main engine coolant system. The temperature at the outlet of the cooler is measured as TCACDs, however the temperature going into the cooler is modeled. The 3.2L engine uses an air to air charge air intercooler and no secondary coolant loop, but is otherwise similar.
To detect a CAC under cooling situation, the efficiency of the cooler is modeled at various speeds and airflows via a 3d speed/airflow multiplier table, providing a modeled cooler out temperature. Cooler efficiency * compressor out temperature = modeled cooler out temp. This modeled cooler out temp is then compared to the measured coolant out temp, if the difference is less than a threshold curve or greater than a threshold, a fault is detected and a pcode is set.
| DTCs | P026A - Charge Air Cooler Efficiency Below Threshold P007E - Charge Air Cooler Temperature Sensor Intermittent/Erratic (Bank 1) |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | ECT, MAP, MAF |
| Typical Monitoring Duration | 4 seconds for fault detection |
| Entry Condition | Minimum | Maximum |
| Engine Speed | 1100 rpm | 3350 rpm |
| Engine Coolant Temperature | 70 deg C | |
| Ambient Air Temperature | - 7 deg C | |
| Barometric Pressure | 74.5 kPa | 110 kPa |
| Ratio of Manifold Absolute Pressure to Barometric Pressure | 1.2 | |
| Intake Air Temperature | - 7 deg C | |
| Injection Quantity | 20mg/stk | 85mg/stk |
| P026A - If the difference of measured temperature and modeled temperature is less than -15 deg C at 0 deg C compressor out temp, or less than -10 deg C at 250 deg C compressor out temp, a fault is set. P007E - If the difference of measured temperature and modeled temperature is greater than 35 deg C a fault is set. |