Circuit Description
The manifold absolute pressure (MAP) sensor responds to changes in intake manifold pressure, indicating the engine load. The MAP sensor has a 5-volt reference circuit, and a signal circuit. The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the signal circuit which is relative to the pressure changes in the manifold. With low manifold absolute pressure such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high manifold absolute pressure such as ignition ON, with the engine OFF or wide-open throttle, the PCM should detect a high MAP sensor signal voltage. Certain vehicle models will also use the MAP sensor in order to calculate the barometric pressure (BARO) when the ignition is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at wide-open throttle. 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 will set.
Conditions for Running the DTC
| • | DTCs P0121, P0122, or P0123 are not set. |
| • | The engine has been running for a length 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. |
| • | The throttle angle is less than 30 percent when the engine speed is more than 3,000 RPM. |
Conditions for Setting the DTC
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. |
Diagnostic Aids
| • | Inspect the MAP sensor vacuum source for leaks, for restrictions, or for poor connections. |
| • | 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 | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
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 Step 3 | |
3 | Does the scan tool indicate that the MAP sensor voltage is more than the specified value? | 4.2 V | Go to Step 5 | Go to Step 4 |
With a scan tool, observe the MAP sensor voltage, while moving the MAP sensor connector, the PCM connector, and the wiring harness related to the MAP sensor. Does the scan tool indicate that the MAP sensor voltage is more than the specified value and holding? | 4.2 V | Go to Step 5 | Go to Diagnostic Aids | |
5 |
Does the scan tool indicate that the MAP sensor voltage is less than the specified value? | 0.1 V | Go to Step 6 | Go to Step 8 |
6 | Connect a DMM between the 5-volt reference circuit of the MAP sensor and the low reference circuit of the MAP sensor. Does the voltage measure within the specified value range? | 4.7-5.2 V | Go to Step 11 | Go to Step 7 |
7 | Does the voltage measure more than the specified value? | 5.2 V | Go to Step 10 | Go to Step 9 |
8 | Test the signal circuit of the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
9 | Test the reference low circuit of the MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
10 | Test the 5-volt reference circuit of the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
11 | Inspect for poor connections at the MAP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Diagnostic Aids |
12 | Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Diagnostic Aids |
13 |
Does the DTC run and pass? | -- | Go to Step 14 | Go to Step 2 |
14 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
