Circuit Description
The barometric pressure (BARO) sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. This gives the powertrain control module (PCM) an indication of the current barometric pressure. The PCM 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 PCM 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 PCM on a signal circuit relative to the pressure changes. The PCM monitors the stability of the BARO sensor output by comparing successive samples. If the PCM detects that the difference between the samples is more than a predetermined amount, DTC P2227 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2227 Barometric Pressure (BARO) Sensor Performance
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0120, P0125, P0128, P0220, P0502, P0503, P0506, P0507, P1182, P1183, P1184, P2135, P2228, P2229 are not set. |
| • | The engine run time is more than 10 seconds. |
| • | The Vehicle Speed parameter is less than 100 kph (60 mph). |
| • | This DTC runs continuously within the enabling conditions in a 250 ms loop. |
Conditions for Setting the DTC
| • | The PCM 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
| • | 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. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |
2 |
Is DTC P2228 or P2229 set? | Go to Step 3 | |
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Inducing Intermittent Fault Conditions in Wiring Systems and Intermittent Conditions |
4 |
Important: The connectors for the following sensors are of the same configuration but are not interchangeable.
Did you find and correct the condition? | Go to Step 8 | Go to Step 5 |
5 | Test for an intermittent and for a poor connection at the BARO sensor. 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 8 | Go to Step 6 |
6 | Test all of the BARO sensor circuits for any intermittent shorts or opens. Refer to Testing for Electrical Intermittents in Wiring Systems. Did you find and correct the condition? | Go to Step 8 | Go to Step 7 |
7 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you complete the action? | Go to Step 8 | -- |
8 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 9 |
9 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |
