For 1990-2009 cars

### Description

The barometric pressure sensor and circuitry are located inside of the powertrain control module. The powertrain control module uses barometric pressure information in order to compensate for altitude changes. The barometric pressure sensor reading is displayed on a scan tool when the ignition switch is ON and the engine is OFF.

### Conditions for Setting the DTC

Input range check indicates that the barometric pressure is less than 33 kPa or greater than 134 kPa.

OR

Input range check indicates that barometric pressure is greater than or equal to 135 kPa.

The above conditions occur when the ignition is ON for 2 seconds and the engine is cranking for 2 seconds.

### Action Taken When the DTC Sets

• | The PCM illuminates the malfunction indicator lamp (MIL).

• | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

• | The PCM enters the Fail-Safe Function and operates as if the barometric pressure is 101 kPa (760 mmHg).

### Conditions for Clearing the MIL/DTC

• | The MIL turns OFF after three consecutively passing trips without a fault present.

• | A History DTC clears after 40 consecutive warm-up cycles without a fault.

• | Use the scan tool Clear DTC Information function or disconnect the PCM battery feed in order to clear the DTC.

### Diagnostic Aids

Barometric pressure varies depending on weather conditions and altitude.

If a DTC P1450 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.

### Test Description

The numbers below refer to the step numbers in 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. This step determines if the fault is present.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Turn ON the ignition, leaving the engine OFF.
2. Clear the scan tool information.
3. Operate the vehicle within the Freeze Frame conditions as specified.

Is DTC P1450 set?

--

Go to Step 3

Go to Diagnostic Aids

3 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 4 | --
4 |

1. Perform the scan tool Clear DTC Information function and road test the vehicle within the Freeze Frame conditions that set the DTC.
2. Review scan tool data and check for DTCs. The repair is complete if no DTCs are stored.

Are any DTCs displayed on the scan tool?

--

Go to the applicable DTC table

System OK