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 B0460 00: Coolant Heater Overheat Sensor Circuit LowDTC B0462 00: Coolant Heater Overheat Sensor Circuit Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Coolant Heater Overheat Sensor Signal | B0460 00 | B0462 00 | B0462 00 | -- |
Coolant Heater Overheat Sensor Low Reference | -- | B0460 00 | -- | -- |
Circuit/System Description
The fuel operated coolant heater uses a overheat sensor to protect the unit for over temperature condition.
Conditions for Running the DTC
Engine is running.
Conditions for Setting the DTC
The fuel operated coolant heater has recognized out of range condition for more than 2.5 seconds.
Action Taken When the DTC Sets
The fuel operated coolant heater is disabled.
Conditions for Clearing the DTC
| • | A current DTC will clear when the conditions for setting the DTC are no longer present. |
| • | A history DTC will clear after 40 malfunction-free ignition cycles. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Air Temperature Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Engine running, observe the scan tool Overheat Temperature Sensor parameter. The parameter should be between 0.09-4.9 volts.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the coolant heater temperature sensor.
- Ignition OFF, test for less than 5 ohms between the low reference circuit and ground.
- Ignition ON, verify the scan tool Overheat Temperature Sensor parameter is greater than 4.5 volts.
- Install a 3A fused jumper wire between the signal circuit and the low reference circuit . Verify the scan tool Overheat Temperature Sensor parameter is less than 0.5 volts.
- If all circuits test normal, test or replace the coolant temperature sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the coolant heater. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the coolant heater. |
| ⇒ | 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 coolant heater. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
