GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 DTC 🢒 DTC P1106

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:

    • A 5-volt reference circuit
    • A low reference circuit
    • A 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 an idle or a deceleration. The PCM should detect a high voltage at a high MAP, such as the ignition is ON with the engine OFF, or at 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
    • DTC P0068, P0120, P0220, P1125, P1516, P2101, P2120, P2121, P2125, P2126, P2130, P2131, P2135 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 4 minutes at less than -30°C (-22°F) to 1 second at more than 30°C (86°F).
    • The throttle angle is 0 percent when engine speed is less than 1,200 RPM.
        OR
    • The throttle angle is less than 20 percent when engine speed is more than 1,200 RPM.

Conditions for Setting the DTC

The PCM detects that the MAP sensor signal voltage is more than 4.9 volts for 20 seconds.

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.

  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-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Start the engine.
  2. Monitor the DTC Information with the scan tool.

Is DTC P0108 or P0641 also set?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

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

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 of for 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 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 Intermittent Conditions and Poor Connections 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 Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you complete the action?

Go to Step 8

--

8
  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 9

9

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK