GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 LeSabre 🢒 Restraints 🢒 SIR 🢒 DTC P1106

Circuit Description

VIN K

The manifold absolute pressure (MAP) sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low 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 MAP sensor signal circuit which is relative to the pressure changes in the manifold. With low MAP, such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP, such as ignition ON, engine OFF, or wide open throttle (WOT), the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 10-104 kPa. The MAP sensor is also used in order to calculate the barometric pressure (BARO) when the ignition switch 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 sets.

VIN 1

The MAP sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The 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 MAP sensor signal circuit which is relative to the pressure changes in the manifold. With low MAP, such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP, such as WOT, the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 8-208 kPa. The MAP sensor is also used in order to calculate the BARO when the ignition switch is turned ON, with the engine OFF. 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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1106 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage

Conditions for Running the DTC

VIN K

    • DTCs P0121, P0122, P0123 are not set.
    • The engine has been running for a length of time that is determined by start-up coolant temperature. The length of 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 engine speed is less than 1,500 RPM.
        OR
    • The throttle angle is less than 10 percent when engine speed is more than 1,500 RPM.

VIN 1

    • DTCs P0121, P0122, P0123 are not set.
    • The engine has been running for a length of time that is determined by start-up coolant temperature. The length of 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 engine speed is less than 900 RPM.
        OR
    • The throttle angle is less than 30 percent when engine speed is more than 900 RPM.

Conditions for Setting the DTC
    • The PCM detects that the MAP sensor signal voltage is intermittently more than 4.2 volts.
    • This diagnostic runs continuously once the above conditions have been met.

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

This DTC may set due to poor idle characteristics. A possible cause may be uncontrolled fueling due to an open or high resistance in the HO2S 1 low signal circuit. Before replacing any component, ensure that this condition does not exist.

Test Description

The number below refers to the step number on the diagnostic table.

  1. Many intermittent open or shorted circuits come and go with harness and connector movement caused by vibration, engine torque, and bumps. This step attempts to recreate the fault which set the DTC.

Step

Action

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 - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Start the engine.
  2. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.

Is DTC P0108 or P0641 also set?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3

  1. Observe the MAP sensor parameter with the scan tool.
  2. Attempt to induce the fault that set the DTC by manipulating the following items:
    3. • The manifold absolute pressure (MAP) sensor wiring harness
    • The MAP sensor electrical connector
    • The powertrain control module (PCM) connector

Refer to Inducing Intermittent Fault Conditions and Intermittent Conditions .

Is the MAP sensor voltage affected during any part of the test?

Go to Step 4

Go to Step 9

4

Test the low reference circuit between the PCM and the MAP sensor for an intermittent open of for high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Important: Disconnecting the PCM may eliminate the short during 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 .

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

Test for an intermittent and for a poor connection at the MAP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

Test the HO2S 1 low signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 8

8

Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you complete the action?

Go to Step 9

--

9
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 10

10

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK