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P00B4





DTC P00B3 or P00B4

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 P00B3
- Radiator Coolant Temperature Sensor Circuit Low Voltage

DTC P00B4
- Radiator Coolant Temperature Sensor Circuit High Voltage

Diagnostic Fault Information






Typical Scan Tool Data






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:






Conditions for Running the DTC

P00B3

* The engine run time is greater than 10 s.

* The intake 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 s.

* The intake 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 s.

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 s.

Action Taken When the DTC Sets

P00B3 and P00B4 are Type B DTCs.

Conditions for Clearing the MIL/DTC

P00B3 and P00B4 are Type B DTCs.

Diagnostic Aids

* As the thermostat opens, the RCT sensor temperature should rise steadily, then stabilize 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 [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Sunshade - Left

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. Ignition ON.

2. Verify the scan tool Radiator Coolant Temperature Sensor parameter is between -39 to + 120°C (-38 to +248°F) and changes with engine run time.

• If not between -39 to + 120°C (-38 to +248°F) or does not change
Refer to Circuit/System Testing.

• If between -39 to + 120°C (-38 to +248°F) and changes

3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

4. Verify the DTC does not set.

• If the DTC sets
Refer to Circuit/System Testing.

• If the DTC does not set

5. All OK.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor 2. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 5 ohms between the low reference terminal 2 and ground.

• If 5 ohms or greater

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.

2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K20 Engine Control Module.

• If less than 5 ohms

3. Ignition ON.

4. Verify the scan tool Radiator Coolant Temperature Sensor parameter is colder than -39°C (-38°F).

• If warmer than -39°C (-38°F)

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.

2. Test for infinite resistance between the signal circuit terminal 1 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the K20 Engine Control Module.

• If colder than -39°C (-38°F)

5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2.

6. Ignition ON, Verify the scan tool Radiator Coolant Temperature Sensor parameter is warmer than 149°C (300°F).

• If colder than the 149°C (300°F)

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, Ignition ON.

2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V

3. Ignition OFF

4. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K20 Engine Control Module.

• If warmer than 149°C (300°F)

7. Test or replace the B34B Engine Coolant Temperature Sensor 2.

Component Testing

1. Ignition OFF, disconnect the harness connector at the B34B Engine Coolant Temperature Sensor 2.

2. Test for refer to Temperature Versus Resistance Electrical Specifications between the signal circuit terminal 1 and the low reference terminal 2.

• If the temperature versus resistance are not within the specified ranges
Replace the B34B Engine Coolant Temperature Sensor 2.

• If the temperature versus resistance are within the specified ranges

3. Test for infinite resistance between each terminal and the sensor housing.

• If less than infinite resistance
Replace the B34B Engine Coolant Temperature Sensor 2.

• If infinite resistance

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Engine Coolant Temperature Sensor Replacement - Radiator Engine Coolant Temperature Sensor Replacement - Radiator

* Engine Control Module Replacement (LCV) Service and RepairEngine Control Module Replacement (LTG) Service and Repair for ECM replacement, programming, and setup.

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