GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2006 🢒 Grand Prix 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P0069

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 provide an overview of each diagnostic category.

DTC Descriptor (L32 ONLY)

DTC P0069 : Manifold Absolute Pressure-Barometric Pressure Correlation

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

5-Volt Reference Circuit

P0069, P0651, P2228, P0530, P0463

P0069

P0069, P2228

P0069

--

Sensor Signal Circuit

P0069, P2228

P0069

P0069, P2228

P0069

--

Low Reference Circuit

--

P0069

P0069, P2229

--

--

Typical Scan Tool Data

BARO Sensor

Circuit

Normal Range

Short to Ground

Open

Short to Voltage

5-Volt Reference Circuit

--

8 kPa

8 kPa

200 kPa

Sensor Signal Circuit

Refer to Altitude Versus Barometric Pressure

8 kPa

8 kPa

200 kPa

Low Reference Circuit

--

--

191 kPa

--

Circuit/System Description

The barometric pressure (BARO) sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. This gives the control module an indication the current of barometric pressure. The control module uses this information to calculate fuel delivery. The BARO sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The control module supplies 5 volts to the BARO sensor on a 5-volt reference circuit, and provides a ground on a low reference circuit. The BARO sensor provides a voltage signal to the control module on a signal circuit relative to the pressure changes. The control module compares the BARO sensor to the manifold absolute pressure (MAP) sensor in order to monitor the BARO sensor operation. If the difference between the two sensors is more than a predetermined amount, DTC P0069 sets.

Conditions for Running the DTC
    • DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0220, P0502, P0503, P2135 are not set.
    • DTCs P2227, P2228, P2229, where applicable, are not set.
    • The ignition is ON.

Conditions for Setting the DTC
    • The control module detects that the difference between the BARO sensor pressure and the MAP sensor pressure is more than 5 kPa when the ignition is ON before engine startup.
        OR
    • The difference between the BARO sensor pressure and the control module predicted BARO is more than 60 kPa when the engine is running.
    • The above conditions are met for 1 second.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Powertrain Control Module Connector End Views
    •  Engine Controls Connector End Views

Electrical Information Reference

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

Special Tools Required

J 23738-A Mityvac

Circuit/System Testing

Always perform the Diagnostic System Check - Vehicle .

  1. If DTCs P0107, P0108, P0641, P0651 are also set, diagnose them first.
  2. Turn OFF the ignition.
  3. Remove the BARO sensor and the MAP sensor.
  4. Inspect each sensor for a plugged port.

    5. Important: The Altitude vs. Barometric Pressure table indicates a pressure range for a given altitude under normal weather conditions. Weather conditions consisting of very low or very high pressure, and/or very low or very high temperature, may cause a reading to be slightly out of range.

  5. Turn ON the ignition, with the engine OFF.
  6. Observe the BARO parameter with a scan tool. Refer to Altitude Versus Barometric Pressure . The BARO parameter should be within the range specified for your altitude.
    7. ⇒If the BARO sensor does not indicate the correct barometric pressure, then test for an intermittent and for a poor connection at the BARO sensor.
  7. Observe the BARO parameter and the MAP Sensor parameter with a scan tool. Compare the values. The difference between the values should be less than 3 kPa.
    8. ⇒If more than 3 kPa, then test for an intermittent and for a poor connection at the MAP sensor.
  8. Turn OFF the ignition.
  9. Connect a J 23738-A to the BARO sensor port.
  10. Turn ON the ignition, with the engine OFF
  11. Monitor the BARO parameter with the scan tool.
  12. Apply vacuum with the J 23738-A SLOWLY, 1 inch Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the BARO sensor pressure.
  13. Increase the vacuum to 20 inches Hg.
    14. ⇒If does not increase smoothly, then test for an intermittent and for a poor connection at the BARO sensor.
  14. Disconnect the J 23738-A from the BARO sensor port. Observe the BARO sensor to see if it returns to the normal range. Refer to Altitude Versus Barometric Pressure .
    15. ⇒If the BARO sensor does not return to the normal range, then replace the BARO sensor.
  15. Turn OFF the ignition.
  16. Remove the MAP sensor from the vacuum source, leaving the harness connected.
  17. Connect a J 23738-A to the MAP sensor port.
  18. Turn ON the ignition, with the engine OFF.
  19. Monitor the MAP sensor parameter with the scan tool.
  20. Apply vacuum with the J 23738-A SLOWLY, 1 inch Hg at a time. Each inch of vacuum should result in a 3-4 kPa drop in the MAP sensor pressure.
  21. Increase the vacuum to 20 inches Hg.
    22. ⇒If MAP sensor parameter does not decrease smoothly during test, then test for an intermittent and for a poor connection at the MAP sensor.
  22. Disconnect the J 23738-A from the MAP sensor port. Observe the MAP sensor to see if it returns to the normal range.
    23. ⇒If does not return to the normal range, then replace the MAP sensor.
  23. Connect a 3A fused jumper wire between the 5-volt reference circuit of the BARO sensor and the signal circuit of the BARO sensor and observe the scan tool parameter for 198 kPa.
    24. ⇒If more than 198 kPa, then replace the BARO sensor.
    ⇒If less than 198 kPa, then test the signal circuit of he BARO sensor for high resistance.
  24. Connect a 3A fused jumper wire between the 5-volt reference circuit of the MAP sensor and the signal circuit of the MAP sensor at the harness connector and observe the scan tool parameter for 4.75 volts.
    25. ⇒If more than 4.75 volts, then replace the MAP sensor.
    ⇒If less than 4.75 volts, then test the signal circuit of he MAP sensor for high resistance.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References
    •  Barometric Pressure Sensor Replacement