DTC P0597-P0599
Diagnostic Instructions
DTC Descriptors
DTC P0597 00: Engine Coolant Thermostat
Heater Control Circuit
DTC P0598 00: Engine Coolant Thermostat
Heater Control Circuit Low Voltage
DTC P0599 00: Engine Coolant Thermostat
Heater Control Circuit High Voltage
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Control High
|
P0597 00, P0598 00
|
P0597 00, P0598 00
|
-
|
-
|
Control Low
|
P0598 00
|
P0598 00
|
P0597 00, P0599 00
|
-
|
Circuit/System Description
The engine control module (ECM) controls the pulse width
modulated (PWM) thermostat. The engine coolant thermostat heater
controls coolant flow and regulates the engine operating
temperature. The ECM supplies 12 V to the thermostat. The ECM
controls the engine coolant thermostat heater by grounding the
control circuit with a solid state device called a driver. The
driver is equipped with a feedback circuit that is pulled-up to a
voltage. The ECM can determine if the control circuit is open,
shorted to ground, or shorted to a voltage by monitoring the
feedback voltage.
Conditions for Running the DTC
• |
The ignition is ON or the engine is running. |
• |
The ignition voltage is greater than
9 V. |
• |
DTC P0597 00, P0598 00, and
P0599 00 run continuously once the above conditions are
met. |
Conditions for Setting the DTC
The ECM detects that the commanded state of the driver and the
actual state of the control circuit do not match for greater than
15 s.
Action Taken When the DTC Sets
DTC P0597 00, P0598 00, P0599 00 are Type B
DTCs.
Conditions for Clearing the DTC
DTC P0597 00, P0598 00, P0599 00 are Type B
DTCs.
Diagnostic Aids
The engine coolant thermostat heater has a mechanical fail-safe
in case of an electrical condition with the engine coolant
thermostat heater. The mechanical thermostat will open at
approximately 104°C (220°F). The mechanical thermostat will
cycle from approximately 104°C (220°F) to approximately
98°C (208°F). The heater is part of the thermostat. The
engine coolant thermostat heater and the thermostat housing are
serviced as an assembly.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
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
- Ignition OFF, disconnect the harness connector at the
E41 Engine Coolant Thermostat Heater.
- Ignition ON, verify that a test lamp illuminates
between the control circuit terminal 2 and ground.
⇒ |
If the test lamp does not illuminate, test the
control circuit for a short to ground or an open/high resistance.
If the circuit tests normal, replace the K20 Engine Control
Module. |
- Verify that a test lamp does not illuminate between
the control circuit terminal 1 and ground.
⇒ |
If the test lamp illuminates, test the control
circuit for a short to voltage. If the circuit tests normal,
replace the K20 Engine Control Module. |
- Ignition OFF, disconnect the X1 harness connector at
the K20 Engine Control Module.
- Test for infinite resistance between the control
circuit terminal 43 X1 and ground.
⇒ |
If less than the specified value, test the control
circuit for a short to ground. |
- Test for less than 5 Ω between the control
circuit terminal 43 X1 at the K20 Engine Control
Module harness connector and terminal 1 at the E41 Engine
Coolant Thermostat Heater harness connector.
⇒ |
If greater than the specified value, test the
control circuit for an open/high resistance. |
- If all circuits test normal, replace the
E41 Engine Coolant Thermostat Heater.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|