Buick Regal: Symptoms - Displays and Gauges

NOTE: The following steps must be completed before using the symptom diagnostic tables.

1. Before using the symptom diagnostic tables, perform the Diagnostic System Check - Vehicle in order to determine that there are no DTCs set, and that the control modules can communicate via the serial data link.

2. Review the system operation in order to understand the system functions. Refer to the following description and operations:

• Instrument Cluster Description and Operation
• Indicator/Warning Message Description and Operation
• Audible Warnings Description and Operation

Visual/Physical Inspection

• Inspect for aftermarket devices which can affect the operation of the instrument panel cluster or the audible warning systems. Refer to Checking Aftermarket Accessories.
• Inspect the accessible system components or the visible system components for obvious damage or for obvious conditions which can cause the symptom.
• Inspect for the proper fluid levels.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• Fuel Gauge Malfunction (with F46 (AWD) ) Fuel Gauge Malfunction (FWD)
• Engine Oil Pressure Indicator Malfunction
• Outside Air Temperature Display Malfunction

Engine Oil Pressure Indicator Malfunction

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 P0521

Engine Oil Pressure Sensor Performance

DTC P0522

Engine Oil Pressure Sensor Circuit Low Voltage.

DTC P0523

Engine Oil Pressure Sensor Circuit High Voltage

Diagnostic Fault Information

1. Engine Oil Pressure Indicator Malfunction

Circuit/System Description

The engine oil pressure sensor changes voltage based on the engine oil pressure. The engine oil pressure sensor is a 3-wire sensor comprising of the signal circuit, the low reference circuit and the 5 V reference circuit. The engine control module (ECM) supplies 5 V to the engine oil pressure sensor via the 5 V reference circuit and provides ground via the low reference circuit. The ECM monitors the signal circuit of the engine oil pressure sensor to determine if the engine oil pressure sensor voltage is within the normal operating range of approximately 1 - 4 V. When the engine oil pressure is high, the engine oil pressure sensor voltage is high and the ECM senses a high signal voltage. When the engine oil pressure is low, the engine oil pressure sensor voltage is low and the ECM senses a low signal voltage. The ECM sends the engine oil pressure information to the instrument cluster via serial data. The instrument cluster will illuminate or display the engine oil pressure indicator when the engine oil pressure is low.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

P0521

• The ECM detects that measured oil pressure is at least 47 kPa (6.8 psi) less than or 50 kPa (7.3 psi) higher than the predicted oil pressure.
• The engine oil pressure is outside of a calculated working range determined by engine speed and temperature.
• The above condition is present for greater than 10 s.

P0522

• The ECM detects that the engine oil pressure sensor signal circuit is less than 0.2 V.
• The above condition is present for greater than 10 s.

P0523

• The ECM detects that the engine oil pressure sensor signal circuit is greater than 4.8 V.
• The above condition is present for greater than 10 s.

Action Taken When the DTC Sets

• The ECM records the operating conditions at the time the diagnostics test fails. The ECM displays this information in the Failure Records on the scan tool.
• The instrument cluster illuminates the engine oil pressure indicator.

Conditions for Clearing the DTC

• The DTC becomes history when the conditions for setting the DTC are no longer present.
• The history DTC clears after 40 malfunction-free warm-up cycles.

Diagnostic Aids

DTC P0521 can set if engine oil pressure is outside the calculated engine oil pressure model stored in the engine control module. This can be an indication of improper engine oil level, poor engine oil condition, or mechanical engine issues causing lower than expected engine oil pressure.

Reference Information

Schematic Reference

Instrument Cluster Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Master Electrical Component List

Description and Operation

• Indicator/Warning Message Description and Operation
• Instrument Cluster Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

With UDD or UDC

1. Verify correct engine oil level and condition.

2. Ignition ON.

3. Verify the engine oil pressure indicator turns on and off when commanding the All Indicators ON and OFF with a scan tool.

• If the engine oil pressure indicator does not turn on and off.

Replace the P16 Instrument Cluster.

• Go to next step: If the engine oil pressure indicator turns on and off

4. Verify the scan tool Engine Oil Pressure Sensor parameter is 0 psi (0 kPa).

• If not 0 psi (0 kPa)

Refer to Circuit/System Testing.

• Go to next step: If 0 psi (0 kPa)

5. Engine running.

6. Verify actual engine oil pressure is within specified range. Refer to Oil Pressure Diagnosis and Testing in Displays and Gauges Component Replacement Reference.

7. Verify the scan tool Engine Oil Pressure parameter is within specified range.

• If not within specified range

Refer to Circuit/System Testing.

• Go to next step: If within specified range

8. Verify the engine oil pressure displayed on Instrument Cluster is within specified range.

• If not within specified range

Test or replace the P16 Instrument Cluster.

• Go to next step: If within specified range

9. All OK.

With UDV or UHS

1. Verify correct engine oil level and condition.

2. Ignition ON.

3. Verify the scan tool Engine Oil Pressure Sensor parameter is 0 psi (0 kPa).

• If not 0 psi (0 kPa)

Refer to Circuit/System Testing.

• Go to next step: If 0 psi (0 kPa)

4. Engine running.

5. Verify actual engine oil pressure is within specified range. Refer to Oil Pressure Diagnosis and Testing in Displays and Gauges Component Replacement Reference.

6. Verify the scan tool Engine Oil Pressure parameter is within specified range.

• If not within specified range

Refer to Circuit/System Testing.

• Go to next step: If within specified range

7. Verify the engine oil pressure displayed on Instrument Cluster is within specified range.

• If not within specified range

Test or replace the P16 Instrument Cluster.

• Go to next step: If within specified range

8. All OK.

Circuit/System Testing

NOTE: Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B37B Engine Oil Pressure Sensor. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal 2 and ground.

• If 10 Ω or greater

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 Ω in the low reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If less than 10 Ω

3. Ignition ON.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 3 and ground.

• If less than 4.8 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the 5 V reference circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the 5 V reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• If greater than 5.2 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the 5 V reference circuit and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K20 Engine Control Module.

• Go to next step: If between 4.8 - 5.2 V

5. Verify the scan tool Engine Oil Pressure parameter is less than 35kPa (5psi).

• If 35kPa (5psi) or above

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 1 and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K20 Engine Control Module.

• Go to next step: If below 35kPa (5psi)

6. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the 5 V reference circuit terminal 3.

7. Engine running.

8. Verify the scan tool Engine Oil Pressure parameter is greater than 800kPa (116psi).

• If 800kPa (116psi) or less

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit terminal 1 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If greater than 800kPa (116psi)

9. Test or replace the B37B Engine Oil Pressure Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Displays and Gauges Component Replacement Reference
• Control Module References for control module replacement, programming and setup

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