B1543

DTC B1543 Oil Temperature Circuit Open:

DTC B1543 Oil Temperature Circuit Open (Part 1 Of 2):

DTC B1543 Oil Temperature Circuit Open (Part 2 Of 2):

CIRCUIT DESCRIPTION
The Instrument Panel Cluster (IPC) receives oil temperature information from the oil temperature sensor. The oil temperature sensor is a thermistor type sensor, which will produce high resistance with low engine oil temperature, while low resistance with high engine oil temperature. The IPC supplies a 5 volt reference signal to the oil temperature sensor. When the engine oil is cold, the sensor resistance will decrease, and the IPC reference voltage level will drop. The IPC measures the reference voltage change and displays the calculated value on the gauge.

CONDITIONS FOR SETTING THE DTC
^ The IPC detects oil temperature less than -10 °C (14 °F)
^ The IPC detects a high voltage level (an open) in oil temperature sensor circuit.
^ The engine must be running for longer than 5 minutes for this DTC to set.

ACTION TAKEN WHEN THE DTC SETS
^ Stores a DTC B1543 in the IPC memory.
^ The PC displays oil temperature as LOW.
^ No driver warning message will be displayed for this DTC.

CONDITIONS FOR CLEARING THE DTC
^ The IPC detects oil temperature above -10 °C (14 °F).
^ The IPC no longer detects a high voltage level (an open) in oil temperature sensor circuit.
^ A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Use the IPC clear DTC feature.
^ Use a scan tool.


DIAGNOSTIC AIDS
^ The following conditions may cause an intermittent malfunction to occur:
- An intermittent open or high resistance in the oil temperature sensor circuit.
- An internal open in the oil temperature sensor.
^ If there is an open in the oil temperature sensor or related wiring, the IPC will display LOW for oil temperature.
^ Check if the IPC is able to recognize a change in resistance from the oil temperature sensor by grounding CKT 357. If the IPC displays oil temperature at approximately 392 °C (200 °F), then the IPC and CKT 357 is not the cause of the malfunction. Check for an open in the oil temperature sensor ground circuit or the sensor itself.

TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table:
2. This test checks the oil temperature data using a scan tool. The scan tool will display oil temperature as -10 °C (14 °F) if there is an open in the oil temperature sensor circuit.
3. This test checks if the IPC is able to recognize a change in resistance by jumping the oil temperature sensor circuit terminals A and B together. The scan tool will display oil temperature at approximately 392 °C (200 °F) when the oil temperature sensor circuit terminals A and B are is shorted to ground.
4. This test checks if the IPC is able to send a 5 volt reference to the oil temperature sensor.
5. This test checks for an opens in the oil temperature sensor ground circuit.