Circuit Description
The manifold absolute pressure (MAP) sensor is a pressure sensor. The control module supplies the MAP sensor a reference voltage, signal, and ground circuits. When manifold vacuum is low, the MAP sensor signal voltage rises to a value near the reference voltage, and the MAP sensor signal voltage decreases when the manifold vacuum increases. The control module monitors the MAP sensor signal circuit voltage in order to calculate the vacuum within the intake manifold.
Certain vehicle models will also use the MAP sensor in order to calculate the barometric pressure (BARO) when the ignition switch is turned ON and the engine is NOT cranked. This BARO reading may also be updated whenever the engine is operated at wide open throttle (WOT).
Conditions for Running the DTC
| • | No active TP sensor DTCs |
| • | No active EGR DTCs |
| • | Any variation in engine speed is less than 75 RPM |
| • | Any variation in throttle position is less than 1.5 % |
| • | Any variation in idle air is less than 4 steps |
| • | The change in EGR flow rate is less than 2 % |
| • | No change in brake switch status |
| • | No change in the clutch switch status (manual transmission) |
| • | No change in A/C clutch status for 2 seconds |
| • | The engine speed is between 400-5,000 RPM |
Conditions for Setting the DTC
The MAP voltage is outside acceptable limits for more than 24 seconds.
Action Taken When the DTC Sets
The VCM turns ON the MIL when 2 failures are reported after 2 consecutive trips. The VCM substitutes a calculated value for the MAP sensor value so an acceptable driving condition is maintained.
Conditions for Clearing the MIL or DTC
| • | The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed. |
| • | A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle. |
| • | Use a scan tool in order to clear the DTCs. |
Diagnostic Aids
Check the MAP sensor vacuum source for leaks, restrictions or poor connections.
Important: The electrical connector must remain securely fastened.
Important: After removing the MAP Sensor from the intake manifold, replace the MAP Sensor to intake manifold seal.
Disconnect the MAP Sensor from the intake manifold and gently twist the sensor in order to check for intermittent connections. Output changes greater than 0.1 volt indicate a bad connector or connection.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Check the MAP sensor output voltage to the VCM. Without the engine running, this voltage represents a barometric reading to the VCM.
Important: When comparing the scan tool readings to a known good vehicle, compare vehicles which use a MAP sensor having the same color insert or the same Hot Stamped number.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and the Failure Records for reference. This data will be lost when the Clear DTC Information function is used. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
2 |
Is the MAP sensor voltage near the first specified value, plus or minus the second specified value? | 4.5V 0.4V | ||
Is the difference greater than the specified value? | 1.5V | Go to Diagnostic Aids | ||
4 | Check the MAP sensor connections. Was a problem found? | -- | ||
5 | Repair the connections as necessary. Refer to Wiring Repairs in Repair Instructions. Is the action complete? | -- | -- | |
6 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement in Repair Instructions. Is the action complete? | -- | -- | |
7 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||
8 | Use the scan tool in order to display the Capture Info and the Review Capture Info functions. Are any DTCs displayed that have not been diagnosed? | -- | Go to The Applicable DTC Table | System OK |
