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 will set.
Conditions for Running the DTC
| • | DTCs P0606, P1120, P1125, P1220, P1221, P1271, P1272, P1273, P1275, P1276, P1280, P1281, P1285, P1286, P1514, P1515, P1516, or P1517 are not set. |
| • | The engine has been running for a period of time that is determined by start-up 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 0.5 percent when engine speed is less than 900 RPM. |
Conditions for Setting the DTC
The MAP sensor signal voltage is more than 4.3 volts for 20 seconds.
Action Taken When the DTC Sets
| • | The PCM stores the DTC in history after the first failure but will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM records the operating conditions at the time the diagnostic runs and fails. The PCM stores the failure information as Freeze Frame/Failure Records. |
Conditions for Clearing the DTC
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
The fault is currently not present. Many intermittent open or shorted circuits come and go with harness and connector movement that is caused by vibration, by engine torque, and by bumps. This step attempts to recreate the fault which set the DTC.
-
This step tests the 5-volt reference circuit for a short to voltage, and tests the low reference circuit for an open.
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 indicate that DTC P1635 or P0108 is current? | -- | Go to Step 3 | |||||||
3 | Does the scan tool indicate that the MAP sensor voltage is greater than the specified value? | 4.3 V | Go to Step 5 | Go to Step 4 | ||||||
With a scan tool, observe the MAP sensor voltage while moving the following components:
Does the scan tool indicate that the MAP sensor voltage is more than the specified value and holding? | 4.3 V | Go to Step 5 | Go to Step 13 | |||||||
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 | ||||||
Measure the voltage from the 5-volt reference circuit to the low reference circuit at the MAP sensor electrical connector. 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 low reference 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 Intermittent Conditions | ||||||
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 Intermittent Conditions | ||||||
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 | |||||||
