P1408

Wiring Diagram:

Circuit Description
The Manifold Absolute Pressure (MAP) sensor measures the change in intake manifold pressure (vacuum). The Powertrain Control Module (PCM) provides a 5 volt reference signal to the MAP sensor. The change in the pressure that results from engine load and RPM changes is converted into a voltage signal that is monitored by the PCM. By monitoring the sensor output voltage, the PCM can detect a change in manifold pressure.

Conditions for Setting the DTC
Signal voltage is greater than 4.8 volts.
^ Engine coolant temperature is greater than 45°C (113°F).
^ Intake air temperature is greater than 5°C (41°F).
^ Throttle position is less than 10 degrees.
Or
Signal voltage is less than 0.2 volts.
^ Engine coolant temperature is greater than 45°C (113°F).
^ Intake air temperature is greater than 5°C (41°F).
^ Throttle position is greater than 5 degrees.

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 consecutive drive cycles without a fault present.
^ A DTC will clear after 40 consecutive warm-up cycles without a fault.
^ The DTCs can be cleared by using a scan tool or by disconnecting the PCM battery feed.

Diagnostic Aids
Check for any of the following conditions:
^ A poor connection at the PCM. Inspect the harness connectors for a backed out terminal, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal to wire connection.
^ Check for proper vacuum hose routing and spilt or pinched vacuum lines.
^ A damaged wiring harness. Inspect the wiring harness for damage and repair as necessary.
If the DTC P1408 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions since 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.
3. Review the Freeze Frame data to determine when the DTC set. Always record this information.
7. This step checks the MAP sensor calibration.