The radiator coolant temperature (RCT) sensor, or engine coolant temperature (ECT) sensor 2, is a variable resistor that measures the temperature of the engine coolant in the radiator. The engine control module (ECM) supplies 5 volts to the RCT signal circuit and supplies a ground to the low reference circuit.

The following table illustrates the difference between temperature, resistance, and voltage:

This DTC sets if one of the following conditions occur for less than 1 second:

DTC P00B6 is a Type B DTC.

DTC P00B6 is a Type B DTC.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. DTC P00B3, P00B4, P0117, P0118, P0597, P0598, or P0599 should not be set.

⇒	If a DTC is set, refer to 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 and Loss of Coolant.
3. Engine idling for 15 minutes with the A/C OFF.

Note: Depending on ambient temperature, it may take up to 4 minutes for the temperatures to equalize.

4. 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 RCT and the ECT sensor parameters. The RCT and the ECT sensor parameters should be within 20°C (68°F).
5. 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.

1. Ignition OFF, disconnect the harness connector at the RCT sensor, or ECT sensor 2.
2. Ignition OFF, test for less than 5 Ω between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify the scan tool RCT sensor parameter is at -40°C (-40°F).

⇒	If greater than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the ECM.

Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.

4. Install a 1 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool RCT sensor parameter is at 150°C (302°F).

⇒	If less than specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the RCT sensor.

1. Ignition OFF, disconnect the harness connector at the RCT sensor.

Note: A thermometer can be used to the used to test the sensor off the vehicle.

2. Test the RCT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance table and verify that the resistance is within 5 percent of the specification.

⇒	If not within the specified range, replace the RCT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.