P1451

Barometric Pressure Sensor Performance:

Circuit Description

The Barometric Pressure Sensor reading is displayed from the Powertrain Control Module (PCM) at ignition switch "ON," engine "OFF" and at wide open throttle. The Barometric Pressure Sensor represents barometric pressure and is used to compensate for altitude changes.


Conditions for Setting the DTC

Comparison with the Manifold Absolute Pressure (MAP) sensor:

^ Difference between barometric pressure and manifold absolute pressure is 67 kPa or more.

^ Key "ON" for 2 seconds and engine cranked for 2 seconds.


Action Taken When the DTC Sets


^ The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the fault active.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.


Conditions for Clearing the MIL/DTC


^ The MIL will turn "OFF" after three consecutively passing cycles without a fault present.

^ A History DTC will clear after 40 consecutive warm-up cycles without a fault.

^ DTC(s) can be cleared by using a scan tool or by disconnecting the PCM battery feed.

Diagnostic Aids


Check The Following Conditions:

^ If any MAP sensor DTC(s) are set, refer to applicable DTC table first.

^ Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

^ Damaged harness. Inspect the wiring harness for damage.

^ Note that barometric pressure varies depending on weather conditions as well as altitude.

If DTC P1451 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

If any wiring repairs need to be made, Refer to Repair Procedures in Diagrams.


Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Determine if fault is present. Review Freeze Frame data to determine when the DTC set. Always record this information. If any MAP sensor DTC(s) are set, refer to applicable DTC table first.