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 senses an intermittent signal voltage lower than the normal range of the sensor, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC.
DTC P1107 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent Low Voltage
MAP Correlation
The following table illustrates the differences between the engine conditions, the MAP sensor values, and the engine vacuum:
Engine Condition | MAP kPa | MAP Voltage | Engine Vacuum |
|---|---|---|---|
Idle | Low | Low | High |
Deceleration | Low | Low | High |
Ignition ON, Engine OFF | High | High | Low |
Wide-Open Throttle | High | High | Low |
Conditions for Running the DTC
| • | The engine is operating. |
| • | DTCs P0106, P0107, P0108, P0121, P0122, and P0123 are not set. |
| • | The throttle position (TP) angle is 0% when the engine speed is less than 800 RPM. |
| OR |
| • | The TP angle is more than 12% when the engine speed is more than 800 RPM. |
| • | DTC P1107 runs continuously once either of the above conditions are met. |
Conditions for Setting the DTC
The MAP sensor voltage is less than 0.4 volts for more than 3 seconds.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the 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. |
Diagnostic Aids
| • | Inspect the MAP sensor vacuum source for leaks, for restrictions, or for poor connections. |
| • | Inspect the engine oil pressure sensor circuits for malfunctions. |
| • | If an intermittent condition exists, refer to Intermittent Conditions . |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
Does DTC P0107 fail this ignition cycle? | Go to DTC P0107 | Go to Step 3 | |
3 |
Does the sensor value change abruptly while a related connector is being moved? | Go to Step 6 | Go to Step 4 |
4 | Observe the affected sensor value on a scan tool while moving the related wiring harnesses. Does the sensor value change abruptly while moving the related electrical harnesses? | Go to Step 7 | Go to Step 5 |
5 |
Does the DTC fail this ignition cycle? | Go to Step 8 | Go to Diagnostic Aids |
6 | Repair the damaged connectors and terminals. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
7 | Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
8 |
Is the action complete? | Go to Step 9 | -- |
9 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 |
10 | With a scan tool, select Capture Info in order to observe the stored information. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |
