Pinpoint Test C : Pinpoint Test: Notes
The Engine Does Not Reach Normal Operating Temperature
Normal operation and Fault Conditions
The secondary cooling system maintains temperatures in the CAC and the fuel cooler during operation. Correct coolant flow through the radiator and the remaining components of the system is essential to maintaining correct temperatures.
Coolant flows primarily from the coolant pump to the radiator circuit and then to the CAC and the fuel cooler from the thermostat. The coolant flows from each component to the degas bottle and then back to the coolant pump. The coolant pump is operated by engine rotation through a pulley which is driven by the accessory drive belt to circulate the coolant. The coolant thermostat are control valves actuated by coolant temperature. When the thermostat is closed, coolant flow bypasses the radiator circuit and flows to the 3 cooling components. When the thermostat is opened, coolant is allowed to flow through the radiator circuit in order to transfer component-generated heat to the outside air.
Concerns of an inability to reach normal operating temperature typically occur when the rate of coolant flow through the radiator is more than expected given the conditions. Heat is not allowed to build in the system because a heat exchanger is removing too much heat, including the radiator, CAC, fuel cooler, or transmission fluid cooler.
Possible Sources
- Low coolant level
- Thermostat
Diagnostic Trouble Code (DTC) Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P007C | CACT Sensor Circuit Low | Indicates a lower than expected air temperature as the air flows out of the CAC. |
| P2184 | ECT Sensor 2 Circuit Low | Indicates lower than expected coolant temperature as the coolant flows out of the radiator. |