To the top of the document
Volt
   
GMDE Start Page Load static TOC Load dynamic TOC Help?

DTC P00B3 or P00B4

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 Descriptors

DTC P00B3:  Radiator Coolant Temperature (RCT) Sensor Circuit Low Voltage

DTC P00B4:  Radiator Coolant Temperature (RCT) Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Coolant Temperature Sensor Signal

P00B3

P00B4

P00B4*

P00B6

Low Reference

-

P00B4

P00B4*

P00B6

* Internal ECM or sensor damage may occur if the circuit is shorted to B+.

Typical Scan Tool Data

Radiator Coolant Temperature Sensor

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Engine Running in Closed Loop

Parameter Normal Range: Varies with ambient temperature

Radiator Coolant Temperature Sensor Signal

140°C (284°F)

-40°C (-40°F)

-40°C (-40°F)*

Low Reference

-

-40°C (-40°F)

-40°C (-40°F)*

* Internal ECM or sensor damage may occur if the circuit is shorted to B+.

Circuit/System Description

The radiator coolant temperature (RCT) 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 RCT signal circuit and supplies a ground to the low reference circuit.

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

RCT

RCT Resistance

RCT Signal Voltage

Cold

High

High

Warm

Low

Low

Conditions for Running the DTC

P00B3

    • The engine run time is greater than 10 seconds.
    • The inlet air temperature (IAT) is colder than 70°C (158°F).
    • The DTC runs continuously when the above conditions are met.

P00B4

    • The engine run time is greater than 60 seconds.
    • The inlet air temperature (IAT) is warmer than -7°C (19°F).
    • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P00B3

The ECM detects that the RCT sensor is warmer than 149°C (300°F) for greater than 10 seconds.

P00B4

Note: The scan tool only displays to -40°C (-40°F).

The ECM detects that the RCT sensor is colder than -60°C (-76°F) for greater than 10 seconds.

Action Taken When the DTC Sets

DTC P00B3 and P00B4 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTC P00B3 and P00B4 are Type B DTCs.

Diagnostic Aids
    • As the thermostat opens, the RCT sensor temperature should rise steadily, then stabilise once the thermostat opens completely.
    • Test the RCT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor.
    • If the vehicle has sat for greater than 8 hours, the RCT sensor and the ECT sensor values should display within 3°C (5°F).

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Hybrid Modes of Operation Description

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Engine running, observe the DTC information with a scan tool. DTCs P00B3 or P00B4 should not set.
  2. 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 B203 engine coolant temperature sensor.
  2. Vehicle OFF, all systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the low reference circuit terminal 1 and ground.
    3. ⇒If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Vehicle in Service Mode, verify the scan tool Radiator Coolant Temperature Sensor parameter is at -40°C (-40°F).
    4. ⇒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 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 2 and the low reference circuit terminal 1. Verify the Radiator Coolant Temperature Sensor parameter is at 140°C (284°F).
    5. ⇒If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  5. If all circuits test normal, test or replace the B203 engine coolant temperature sensor.

Component Testing
  1. Vehicle OFF, remove the B203 engine coolant temperature sensor.

    2. Note: A thermometer can be 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.
    3. ⇒If not within the specified range, replace the B203 engine coolant temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Engine Coolant Temperature Sensor Replacement
    • Control Module References for ECM replacement, setup, and programming
   


&#169© Copyright Chevrolet. All rights reserved