Circuit 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 action into electrical resistance. The BARO sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The BARO sensor provides a signal voltage to the ECM, relative to the pressure changes on the BARO sensor signal circuit. The ECM converts the signal voltage input to a pressure value.
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 4267 meters (14,000 feet), to 105 kPa at or below sea level. The BARO sensor has a range of 8-207 kPa. The ECM uses the BARO sensor input for fuel delivery and other diagnostics.
Within the ECM, the diagnostic compares the BARO sensor input to the boost pressure sensor input. If the ECM detects that the inputs are not within a specified amount of each other, DTC P2227 sets.
DTC Descriptor
The following procedure supports the following DTC:
DTC P2227 Barometric Pressure (BARO) Sensor Performance
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0237, P0238, P0299, P0335, P0336, P0500, P2228, P2229 is not set. |
| • | The engine speed is between 580-900 RPM. |
| • | The engine run time is more than 8 seconds. |
| • | The vehicle speed is less than 40 km/h (25 mph). |
| • | The accelerator pedal position (APP) is less than 69 percent. |
| • | The engine coolant temperature is more than 20°C (68°F). |
| • | The mass air flow (MAF) is less than 50 g/s. |
| • | The power take-off (PTO) is not active. |
| • | The above conditions are met for 5 seconds. |
| • | DTC P2227 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The ECM detects that the difference between the BARO pressure and the boost pressure is more than 15 kPa for 6 seconds.
Action Taken When the DTC Sets-Federal
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The MIL will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Action Taken When the DTC Sets-California
| • | 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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the ability of the boost pressure sensor to correctly indicate barometric pressure.
-
This step tests the circuits and the controller output.
-
This step test the circuits and the controller output.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |
2 |
Is the BARO parameter within the range specified? | -- | Go to Step 3 | Go to Step 7 |
Is the Boost Pressure Sensor parameter within the range specified? | -- | Go to Step 4 | Go to Step 13 | |
4 |
Does the BARO parameter decrease? | -- | Go to Step 5 | Go to Step 24 |
5 |
Does the BARO parameter change more than the specified value? | 15 kPa | Go to Step 7 | Go to Step 6 |
6 |
Is the difference between the Boost Pressure Sensor parameter and the BARO parameter more than the specified value? | 15 kPa | Go to Step 13 | Go to Intermittent Conditions |
7 | Test for an intermittent and for a poor connection at the BARO sensor connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 8 |
Is the amperage more than the specified value? | 170 mA | Go to Step 9 | Go to Step 10 | |
9 |
Is the pressure more than the specified value? | 205 kPa | Go to Step 24 | Go to Step 19 |
10 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 11 |
11 |
Is the resistance more than the specified value? | 5 ohms | Go to Step 23 | Go to Step 12 |
12 | Measure the resistance of the low reference circuit between the BARO sensor and the ECM, with a DMM. Is the resistance more than the specified value? | 5 ohms | Go to Step 23 | Go to Step 26 |
13 | Test for an intermittent and for a poor connection at the boost pressure sensor connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 14 |
Is the amperage more than the specified value? | 170 mA | Go to Step 15 | Go to Step 16 | |
15 |
Is the resistance more than the specified value? | 5 ohms | Go to Step 23 | Go to Step 20 |
16 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 17 |
17 |
Is the resistance more than the specified value? | 5 ohms | Go to Step 23 | Go to Step 18 |
18 | Measure the resistance of the low reference circuit between the boost pressure sensor and the ECM, with a DMM. Is the resistance more than the specified value? | 5 ohms | Go to Step 23 | Go to Step 26 |
19 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 21 |
20 |
Is the Boost Pressure Sensor parameter more than the specified value | 254 kPa (36 PSI) | Go to Step 25 | Go to Step 22 |
21 |
Is the resistance more than the specified value? | 5 ohms | Go to Step 23 | Go to Step 26 |
22 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 26 |
23 | Repair the high resistance in the circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 27 | -- |
24 | Replace the BARO sensor. Refer to Barometric Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 27 | -- |
25 | Replace the boost pressure sensor. Refer to Turbocharger Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 27 | -- |
26 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 27 | -- |
27 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 28 | |
28 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
