P0069–MANIFOLD PRESSURE/BAROMETRIC PRESSURE CORRELATION

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

The Barometric/Atmospheric Pressure Sensor is calculated from the Inlet Pressure Sensor Signal. The ECM compares the signal of the Inlet Pressure Sensor to the signal of the Boost Pressure Sensor during key on, engine off and during after-run mode to determine the plausibility of these sensors.

When Monitored:
Engine not running. There are no Sensor Reference Voltage DTC's. There are no other Boost Pressure related DTC's. There are no Inlet Pressure Sensor DTC's.
Set Condition:
The difference between the Boost Pressure Sensor Signal and the Inlet Pressure Sensor Signal is greater than 100 hpa (1.45 psi).

Possible Causes

BOOST PRESSURE SENSOR RELATED WIRING & CONNECTORS

BOOST PRESSURE SENSOR

INLET PRESSURE SENSOR RELATED WIRING & CONNECTORS

INLET PRESSURE SENSOR

ENGINE CONTROL MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Diagnostic Test

1. CHECK FOR ACTIVE DTCS IN THE ECM

NOTE: Verify and note actual Atmospheric/Barometric pressure.

Ignition on, engine not running.
With the scan tool, Clear DTCs in the Engine Control Module (ECM).
Monitor the scan tool for at least two minutes.
Cycle the ignition key off and on several times, leaving the ignition on for at least 10 seconds at a time.
Turn the ignition on.
With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

Go To 2

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.

2. ECM

With the scan tool, view the ECM Data and read the Atmospheric Pressure.
Compare ECM Atmospheric Pressure reading to the actual atmospheric pressure.

Does the scan tool display Atmospheric Pressure that is within 150 hpa (2.175 psi.) of actual atmospheric pressure?

Yes

Go To 3

Check the wiring connectors between the Inlet Pressure Sensor and the ECM for high resistance, poor terminal contact, corrosion or other problems. If Inlet Pressure Sensor wiring and connectors check out good, replace the Inlet Pressure Sensor.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

3. BOOST PRESSURE SENSOR WIRING INSPECTION

Turn the ignition off.
Using the wiring schematics as a guide, inspect the wiring and connectors associated with the Boost Pressure Sensor circuits between the Boost Pressure Sensor and the ECM.

Were any problems found?

Yes

Repair or replace wiring/connectors as necessary.

Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Replace the Boost Pressure Sensor.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)