P2227

DTC P2227

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P2227
- Barometric Pressure (BARO) Sensor Performance

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The barometric pressure (BARO) sensor measures the pressure of the atmosphere. This pressure is affected by altitude and weather conditions. A diaphragm within the BARO sensor is displaced by the pressure changes that occur from varying altitudes and weather conditions. The sensor translates this diaphragm action into the voltage signal input that is used by the engine control module (ECM) for diagnostics, emissions control, and to calculate fuel delivery.

Changes in BARO due to weather are relatively small, while changes due to altitude are significant. Pressure can range from 56 kPa at an altitude of 4 267 meters (14,000 feet), to 104 kPa at or below sea level.

The sensor has the following circuits:

* An ECM supplied and regulated 5-volt reference circuit
* An ECM supplied ground for the low reference circuit
* A sensor signal circuit that supplies a voltage input to the ECM

The control module monitors the stability of the BARO sensor output by comparing successive samples. If the control module detects that the difference between the samples is more than a predetermined amount, DTC P2227 sets.

Conditions for Running the DTC

* DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0220, P0502, P0503, P2135, P2228, P2229 are not set.
* The engine run time is more than 10 seconds.

Conditions for Setting the DTC

* The control module detects that 80 out of 100 consecutive BARO sensor samples vary more than 10 kPa between each sample.
* The above condition is met for 10 seconds.

Action Taken When the DTC Sets

DTC P2227 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P2227 is a Type B DTC.

Diagnostic Aids

If the BARO parameter DOES NOT fluctuates rapidly, refer to Inducing Intermittent Fault Conditions. Component Tests and General Diagnostics

Special Tools Required

J 35555 Metal Mityvac

Circuit/System Verification

1. Ignition ON, observe the scan tool MAP, SC Inlet Pressure, and BARO sensor parameters. The readings should be within 5 kPa of each other and also the current BARO for your location. Refer to Altitude Versus Barometric Pressure.
2. Engine running, observe the DTC information with a scan tool. DTC P2227 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

Circuit/System Testing

Start the vehicle and monitor the BARO parameter with the scan tool for a steady value.

If the BARO parameter fluctuates rapidly.

* Test for an intermittent and for a poor connection at the BARO sensor.
* Test for proper BARO wiring harness routing.
* Test all of the BARO sensor circuits for intermittent shorts or opens.
* Test for an intermittent and for a poor connection at the control module.

• If the circuits test normal, replace the BARO sensor.

Component Testing

Important: You must perform the Circuit/System Testing before proceeding with the Component Test.

1. Turn ON the ignition with the engine OFF and remove the BARO sensor.
2. Install a 3A fused jumper wire between the 5-volt reference terminal C of the sensor and 5-volt reference.
3. Install a jumper wire between the low reference terminal A of the sensor and ground.
4. Install a jumper wire at the signal terminal B of the BARO sensor.
5. Connect a DMM between the jumper wire from terminal B of the sensor and ground.
6. Install the J 35555 to the BARO sensor vacuum port. Slowly apply vacuum to the sensor while monitoring the voltage on the DMM. The voltage should vary between 5.2-0 volts, without any spikes or dropouts.

• If the voltage is not within the specified range or is erratic, replace the BARO sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Control Module References for ECM replacement, setup, and programming Programming and Relearning
* Barometric Pressure Sensor Replacement