Circuit Description
The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits:
| • | 5-volt reference circuit |
| • | Low reference circuit |
| • | MAP sensor signal circuit |
The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used in order to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.
If the PCM detects a MAP sensor signal voltage that is excessively high, DTC P0108 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage
Conditions for Running the DTC
| • | DTCs P0068, P0120, P0122, P0123, P0220, P0222, P0223 P1516, P1680, P1681, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2176 are not set. |
| • | The throttle position (TP) is less than 15 percent. |
| • | The vehicle speed is less than 2 km/h (1 mph). |
| • | The engine run time is greater than 40 seconds. |
| • | DTC P0108 runs continuously when the above conditions are met. |
Conditions for Setting the DTC
The PCM detects that the MAP sensor voltage is more than 4.2 volts for more than 1 second.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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 | Values | 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 - Vehicle? | -- | Go to Step 2 | |||||||
2 |
Is the voltage more than the specified value? | 4.2 V | Go to Step 4 | Go to Step 3 | ||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections | ||||||
4 | Inspect the MAP sensor vacuum source for the following conditions:
Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 5 | ||||||
5 | Monitor the DTC Information with the scan tool. Is DTC P0651 also set? | -- | Go to Step 9 | Go to Step 6 | ||||||
6 | Test for an intermittent and for a poor connection at the MAP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 7 | ||||||
7 |
Is the voltage less than the specified value? | 0.2 V | Go to Step 8 | Go to Step 10 | ||||||
8 |
Is the voltage more than the specified value? | 0.2 V | Go to Step 11 | Go to Step 13 | ||||||
9 |
Is the voltage less than the specified value? | 0.2 V | Go to DTC P0651 | Go to Step 10 | ||||||
10 | Test the MAP sensor signal circuit between the powertrain control module (PCM) and the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||
11 | Test the low reference circuit between the PCM and the MAP sensor for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 | ||||||
12 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||
13 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||
14 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||
15 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 16 | ||||||
16 | Observe the Capture Info with a scan tool. Have any other DTCs not been diagnosed? | -- | System OK | |||||||
