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 (RCT) Sensor Circuit Low Voltage
DTC P00B4
- Radiator Coolant Temperature (RCT) 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 radiator coolant. The ECM supplies 5 V to the RCT sensor signal circuit and supplies a ground for the low reference circuit.
Conditions for Running the DTC
* The ignition is ON, or the engine is running.
* The battery voltage is greater than 9 V.
* The intake air temperature (IAT) is warmer than -30°C (-22°F) or the IAT is colder than -30°C (-22°F) and the engine run time is greater than 120 s.
* This DTC runs continuously within the enabling conditions.
Conditions for Setting the DTC
P00B3
The ECM detects that the RCT sensor signal is less than 0.27 V, which is warmer than 137°C (279°F) for greater than 2 s.
P00B4
The ECM detects that the RCT sensor signal is greater than 4.96 V, which is colder than-39°C (-38°F) for greater than 2 s.
Action Taken When the DTC Sets
* DTCs P00B3 and P00B4 are Type B DTCs.
* The cooling fans will be commanded ON.
* The A/C compressor will be commanded OFF.
Conditions for Clearing the DTC
DTCs P00B3 and P00B4 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Cooling System Description and Operation (Cooling System)
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 (Programming and Relearning)for scan tool information
Circuit/System Verification
1. If the ignition has been OFF for 8 h or greater, the IAT, the ambient air temperature, and the RCT should be within 9°C (16°F) of each other. Ignition ON, observe the scan tool IAT Sensor, Ambient Air Temperature, and the RCT sensor. Compare those sensor parameters to each other to determine if the condition is current.
2. Engine running, observe the RCT Sensor parameter. The reading should be between -39 to +120°C (-38 to +248°F) depending on the current Ambient Air Temperature, the engine run time, and the vehicle operating conditions.
3. 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. Ignition OFF, disconnect the harness connector at the B34B Radiator Coolant Temperature Sensor.
2. Ignition OFF, test for less than 5 ohm 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 K20 Engine Control Module.
3. Ignition ON, verify the scan tool RCT sensor parameter is at -40°C (-40°F).
• If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.
4. Install a 3 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 greater than 142°C (288°F).
• If greater than the 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 Radiator Coolant Temperature Sensor.
Component Testing
Static Test
Measure and record the resistance of the B34B Radiator Coolant Temperature Sensor at various ambient air temperatures, then compare those measurements to the Temperature Versus Resistance () table.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning)for ECM replacement, setup, and programming