Circuit Description
The manifold absolute pressure (MAP) sensor responds to changes in intake manifold pressure, vacuum. The MAP signal voltage to the engine control module (ECM) varies from below 2 volts at idle, high vacuum, to above 4 volts with the key in the ON position, engine not running. or at wide open throttle (WOT), low vacuum.
A speed density method of determining engine load is used. This is calculated using inputs from the MAP sensor, the RPM (58X), and the intake air temperature (IAT) sensor. The MAP sensor is the main sensor used in this calculation, and measuring engine load is its main function.
The ECM compares the MAP sensor signal to calculated MAP based on throttle position (TP) and various other engine load factors. If the ECM detects a MAP signal voltage that is intermittently above the calculated value, DTC P1106 will set.
Conditions for Setting the DTC
| • | The MAP is greater than 103 kPa (15 psi). |
| • | No TP sensor fail conditions are present. |
| • | The engine is running more than 10 seconds. |
| • | The TP sensor is less than 20 percent if RPM is less than 3,000. |
| • | The TP sensor is less than 30 percent if RPM is greater than 3,000. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The ECM will store conditions which were present when the DTC was set as Failure Records data only. |
| • | This information will not be stored in the Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Diagnostic Aids
Inspect for the following conditions:
| • | Leaking or plugged vacuum supply line to the MAP sensor |
| • | Inspect the ECM harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal-to-wire connection. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, observe the MAP display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault. |
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Yes | No |
|---|---|---|---|
1 | Perform an On-Board Diagnostic System Check. Was the check performed? | Go to Step 2 | |
2 |
Is DTC P0108 also set? | Go to applicable DTC table | Go to Step 3 |
3 | Inspect for a poor sensor ground circuit terminal A connection at the manifold absolute pressure (MAP) sensor. Is a repair necessary? | Go to Step 7 | Go to Step 4 |
4 | Inspect the MAP signal circuit between the MAP sensor connector and engine control module (ECM) for an intermittent short to voltage. Is a repair necessary? | Go to Step 7 | Go to Step 5 |
5 | Inspect for an intermittent short to voltage on the 5-volt reference A31 circuit between the MAP sensor and ECM. Is a repair necessary? | Go to Step 8 | Go to Step 6 |
6 | Inspect for a poor sensor ground circuit terminal A16 connection at the ECM. Is a repair necessary? | Go to Step 7 | Go to Step 9 |
7 | Repair the faulty harness connector terminal for sensor ground circuit or replace it. Did you complete the repair? | Go to Step 9 | -- |
8 | Locate and repair intermittent open or short circuit in the wiring harness as needed. Did you find and correct the condition? | Go to Step 9 | -- |
9 |
Does the scan tool indicate that this diagnostic has run and passed? | Go to Step 10 | Go to Step 2 |
10 | Are any DTCs displayed that have not been diagnosed? | Go to applicable DTC table | System OK |
