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 intermittently high, DTC P1106 sets.
Conditions for Running the DTC
| • | DTCs P0121, P0122, or P0123 are not set. |
| • | The engine has been running for a period of time that is determined by the startup coolant temperature. The time ranges from 2 minutes at less than -30°C (-22°F) to 1 second at more than -30°C (86°F). |
| • | The throttle angle is less than 2 percent when the engine speed is less than 3,000 RPM. |
| OR |
| • | The throttle angle is less than 30 percent when the engine speed is more than 3,000 RPM. |
Conditions for Setting the DTC
The PCM detects that the MAP sensor voltage is intermittently more than 4.2 volts.
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the DTC
| • | 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 non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Test Description
The number below refers to the step number on the diagnostic table.
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-Engine Controls? | -- | Go to Step 2 | |||||||
2 |
Does the scan tool display DTC P1635 or P0108 set? | -- | Go to DTC P1635 | Go to Step 3 | ||||||
Refer to Inducing Intermittent Fault Conditions in Wiring Systems and Intermittent Conditions . Is the MAP sensor voltage affected during any part of the test? | -- | Go to Step 4 | Go to Step 8 | |||||||
4 | Test the low reference circuit between the PCM and the MAP sensor for an intermittent open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 5 | ||||||
5 |
Important: Disconnecting the PCM may eliminate the short during the testing. Test the MAP sensor signal circuit between the PCM and the MAP sensor for an intermittent short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 6 | ||||||
6 | Test for an intermittent and for a poor connection at the MAP sensor. Refer to Testing for Continuity and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 7 | ||||||
7 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Continuity and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | |||||||
8 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 9 | ||||||
9 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||
