P00B7
DTC P00B7
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P00B7
- Radiator Coolant Temperature (RCT) Insufficient Flow
Diagnostic Fault Information
Typical Scan Tool Data
Circuit Description
The engine control module (ECM) monitors the temperature of the engine radiator coolant. The ECM controls the thermostat with a pulse width modulated (PWM) signal. The ECM compares the radiator coolant temperature to the engine coolant temperature in order to determine if there sufficient coolant flow through the thermostat.
Conditions for Running the DTC
* DTCs P00B3, P00B4, P00B6, P0116, P0117, and P0118 are not set.
* The engine run time is greater than 5 m.
OR
* The engine coolant temperature is greater than 105°C (221°F).
* The DTC runs continuously when the above conditions are met.
Conditions for Setting the DTC
Note: The scan tool display range is between -40 and + 150°C (-40 and +302°F).
The ECM detects the difference between the RCT sensor and the ECT sensor is greater than 30°C (86°F) when the ECT sensor is warmer than 117°C (242°F) for greater than 5 s.
Action Taken When the DTC Sets
DTC P00B7 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P00B7 is a Type B DTC.
Diagnostic Aids
* The thermostat has a mechanical fail-safe in case of an electrical condition with the thermostat heater. The mechanical thermostat will open at approximately 80°C (176°F). The mechanical thermostat will cycle from approximately 85°C (185°F) to approximately 102°C (215°F).
* A resistance condition in the RCT sensor circuits may cause this DTC. This condition results in a greater voltage on the RCT sensor signal circuit, which is interpreted by the ECM as a colder RCT.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Engine Running, observe the DTC information with a scan tool. DTC P00B3, P00B4, P00B6, P0117, P0118, P0597, P0598, and P0599 should not be set.
• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
2. Verify the coolant in the radiator surge tank is at the correct level and there are no engine coolant leaks. Refer to Cooling System Draining and Filling Cooling System Draining and Filling and Loss of Coolant Loss of Coolant.
3. Verify the engine cooling fan operates. Refer to Cooling Fan Inoperative (LUV) Cooling Fan InoperativeCooling Fan Inoperative (LUW, LWE) Cooling Fan Inoperative.
4. Engine idling for 15 minutes with the A/C OFF.
Note: Depending on ambient temperature, it may take up to 4 minutes for the temperature to decrease less than the specified value.
5. Command the Engine Coolant Thermostat Heater to 100 percent with a scan tool. Increase the engine speed to 3,000 RPM. Observe the scan tool ECT sensor parameter. The temperature should decrease to less than 85°C (185°F).
6. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
Circuit/System Testing
1. Vehicle OFF, inspect the cooling system for the conditions below. Refer to Symptoms - Engine Cooling Symptoms - Engine Cooling.
* Weak coolant solution
* Obstructed radiator air flow or bent radiator fins
* Blocked cooling system passages
* Radiator hoses that are restricted, collapsed, or deteriorated
* Damaged water pump and or belt
* Loss of cooling system pressure
- Leaking surge tank cap
- Radiator hoses
* Cylinder head or an engine block that is cracked or plugged
• If you find any of the above conditions, repair as necessary.
2. If all conditions test normal, replace the E41 engine coolant thermostat heater.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Engine Coolant Thermostat Replacement (LUV) Service and RepairEngine Coolant Thermostat Replacement (LUW) Service and Repair