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 provide an overview of each diagnostic category. |
DTC Descriptors
DTC B0481 00 : Overheat Detected, Software LevelDTC B0482 00 : Overheat Detected, Hardware Level
DTC B0483 00 : Overheat Possible
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Coolant Heater Overheat Sensor Supply Voltage Circuit | B0460 00 | B0462 00 | -- | B0481 00 B0482 00 B0483 00 |
Coolant Heater Overheat Sensor Ground Circuit | -- | B0460 00 | B0462 00 | B0481 00 B0482 00 B0483 00 |
Circuit/System Description
The fuel operated heater uses a coolant heater overheat sensor to protect the unit for over temperature conditions. The fuel operated heater also uses Overheat Detection software.
Conditions for Running the DTC
Engine is running.
Conditions for Setting the DTC
Fuel operated heater has recognized out of range condition for more than 2.5 seconds.
Action Taken When the DTC Sets
Fuel operated heater is disabled.
Conditions for Clearing the DTC
DTC must be cleared with a scan tool.
Reference Information
Schematic Reference
Connector End View Reference
Cooling System Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Start the vehicle. Observe the coolant heater over heat sensor scan tool parameter . The scan tool parameter should display between 0.09-4.9 volts.
Component Testing
- Ignition OFF, disconnect the 14-pin coolant heater module connector from the module.
- Test the coolant heater over heat sensor resistance.
- Compare the readings with the Temperature vs Resistance table and verify that the resistance is within 5 percent of the specification.
- If the coolant heater overheat sensor tests normal, replace the coolant heater.
| ⇒ | If the resistance vs temperature reading is not within 5 percent, replace the coolant heater overheat sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
