Chevrolet Trax: DTC P00B6 (2H0 OR LUJ): Radiator coolant temperature (RCT) Sensor

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category

DTC Descriptor

DTC P00B6

Radiator Coolant Temperature (RCT)-Engine Coolant Temperature (ECT) Not Plausible

Diagnostic Fault Information

Typical Scan Tool Data

Radiator Coolant Temperature Sensor

Circuit Description

The engine coolant temperature sensor 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 engine coolant temperature signal circuit and supplies a ground to the low reference circuit. The purpose of this diagnostic is to determine if the input from the RCT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the engine is OFF. If the required engine OFF time is met at start-up, the ECM will compare the temperature difference between the actual measured RCT and ECT sensors.

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

Conditions for Running the DTC

• DTCs P00B3, P00B4, P00B6, P0112, P0113, P0117, P0118, P0502, P0503 or P2610 are not set.
• The vehicle has been OFF for greater than 8 hours before vehicle ON.
• The vehicle is ON, or the engine is running.
• The intake air temperature (IAT) is warmer than -7ºC (19ºF).
• The fuel level is greater than 10 percent.
• The DTC runs once per ignition cycle when the above conditions are met.

Conditions for Setting the DTC

The ECM determines the absolute difference of temperature between the RCT start up temperature and ECT start up temperature is greater than 20ºC (68ºF) .

Action Taken When the DTC Sets

DTC P00B6 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P00B6 is a Type B DTC.

Diagnostic Aids

• As the thermostat opens, the radiator coolant temperature sensor signal should rise steadily, then stabilize once the thermostat opens completely.
• Inspect for the correct operation of the engine cooling system and verify the correct coolant level.

Reference Information

Schematic Reference

Engine Heating/Cooling Schematics (Encore), Engine Heating/Cooling Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Engine running, 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 radiator coolant temperature sensor and ECT sensor parameters. The radiator coolant temperature sensor and the ECT sensor parameters should be within 20ºC (68ºF).
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.

Circuit/System Testing

1. Vehicle OFF, disconnect the harness connector at the B34B engine coolant temperature sensor.
2. Vehicle OFF, all systems OFF. This may take up to 2 minutes for all vehicle systems to power down.

   Test for less than 5 ohms between the low reference circuit terminal 1 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 K20 engine control module.

3. Vehicle ON, verify the scan tool Radiator Coolant Temperature Sensor parameter is at -40ºC (-40ºF).

• If warmer than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 engine control module.

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 2 and the low reference circuit terminal 1. Verify the scan tool Radiator Coolant Temperature Sensor parameter is at 140ºC (284ºF).

• 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 K20 engine control module.

5. If all circuits test normal, test or replace the B34B engine coolant temperature sensor.

Component Testing

1. Vehicle OFF, remove the B34B engine coolant temperature sensor.

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

2. Test the engine coolant temperature 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 B34B engine coolant temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Engine Coolant Temperature Sensor Replacement (Water Outlet) , Engine Coolant Temperature Sensor Replacement (Radiator)
• Engine Control Module Replacement for ECM replacement, setup, and programming

READ NEXT: