GM Service Manual Online
For 1990-2009 cars only

Object Number: 469072  Size: MF
Instrument Cluster Components
Instrument Cluster: Analog Schematics
Handling Electrostatic Discharge Sensitive Parts Notice

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 IPC 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:

  1. 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.

  2. 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.

  3. This test checks if the IPC is able to send a 5 volt reference to the oil temperature sensor.

  4. This test checks for an opens in the oil temperature sensor ground circuit,

DTC B1543 -- Oil Temperature Circuit Open

Step

Action

Value(s)

Yes

No

1

Were you sent here from the IPC Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

Using a scan tool, select IPC data display and monitor the oil temperature data.

Does the scan tool display oil temperature data less than the specified value?

-10°C (14°F)

Go to Step 3

Go to Step 6

3

  1. Disconnect the oil temperature sensor connector.
  2. At the oil temperature sensor (harness side), jumper terminals A and B together.
  3. Using a scan tool, select IPC data display and monitor the oil temperature sensor data.

Does the scan tool display oil temperature data more than the specified value?

190°C (374°F)

Go to Step 8

Go to Step 4

4

  1. Remove the jumper wire.
  2. At the oil temperature sensor connector (harness side), measure the voltage between terminal B and ground.

Was the voltage indicated between the specified value?

4.5-5.5 V

Go to Step 5

Go to Step 9

5

At the oil temperature sensor connector (harness side), check for continuity between terminal A and ground.

Is there continuity?

--

Go to Step 7

Go to Step 10

6

Check the oil temperature sensor circuit for an intermittent malfunction. Refer to Diagnostic Aids.

Was a problem found and repaired?

--

Go to Step 12

Go to Step 7

7

  1. Turn OFF the ignition switch.
  2. Reconnect or install any connectors or components that were disconnected or removed.
  3. Turn ON the ignition switch.
  4. Clear any DTCs.
  5. Run engine for 5 minutes.

Does DTC B1543 set as current?

--

Go to Step 11

System OK

8

Replace the oil temperature sensor.

Is the replacement complete?

--

Go to Step 12

--

9

Check for an open or short in CKT 357.

Was a problem found and repaired?

--

Go to Step 12

Go to Step 11

10

Check for an open or short in CKT 470.

Was a problem found and repaired?

--

Go to Step 12

Go to Step 11

11

Replace the IPC assembly. Refer to Instrument Cluster Replacement .

Is the replacement complete?

--

Go to Step 12

--

12

  1. Turn OFF the ignition switch.
  2. Reconnect or install any connectors or components that were disconnected or removed.
  3. Turn ON the ignition switch.
  4. Clear any DTCs.

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

--