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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Astro - 2WD 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 DTC P1106 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage

Object Number: 600262 Size: MF
Engine Controls Components
Fuel Mixture Input Controls
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The manifold absolute pressure (MAP) sensor is a pressure sensor. The control module supplies the MAP sensor a reference voltage, signal, and ground circuits. When manifold vacuum is low, the MAP sensor signal voltage rises to a value near the reference voltage, and the MAP sensor signal voltage decreases when the manifold vacuum increases. The control module monitors the MAP sensor signal circuit voltage in order to calculate the vacuum within the intake manifold.

Certain vehicle models will also use the MAP sensor in order to calculate the barometric pressure (BARO) when the ignition switch is turned ON and the engine is NOT cranked. This BARO reading may also be updated whenever the engine is operated at wide open throttle (WOT).

This DTC is designed to detect intermittent high voltage signals on the MAP sensor circuit.

Conditions for Running the DTC
    • No active throttle position (TP) sensor DTCs
    • The throttle position is more than 0.4 percent with an engine speed of more than 1,200 RPM.
        OR:
        The throttle position is more than 20 percent with an engine speed of more than 1,200 RPM.

Conditions for Setting the DTC

The vehicle control module (VCM) detects an intermittent high MAP sensor voltage after a calibrated amount of time.

Action Taken When the DTC Sets
    • The control module stores the DTC in history after the first failure but will not illuminate the malfunction indicator lamp (MIL).
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores the failure information in the scan tools Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC
    • A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles.
    • A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle.
    • Use the scan tool Clear Information function.

Diagnostic Aids

With the ignition ON and the engine OFF, the manifold pressure is equal to the atmospheric pressure with the signal voltage high. The VCM uses this information as an indication of the vehicles altitude. Comparison of this reading with a known good vehicle using the same sensor is a good way to check the accuracy of a suspect sensor. The readings should be within 0.4 volts of each other. This DTC could set if the sensor ground circuit is intermittently open or the MAP sensor signal circuit is intermittently shorted to voltage.

Inspect for intermittents.

An intermittent may be caused by any of the following conditions:

    • A poor connection
    • Rubbed through wire insulation
    • A broken wire inside the insulation

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. If the MAP sensor signal is more than 4.6 volts, the condition is present. Even though DTC P0108 is not set, the P0108 table is more comprehensive and may aid in diagnosis.

    2.

  2. The engine must be running in order to observe the MAP sensor signal voltage.

Step

Action

Values

Yes

No

1

Important: Be sure to use the same diagnostic equipment for all measurements.

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Install a vacuum gauge.
  2. Correct any of the following conditions before using this table:
    3. • The engine idle is unstable
    • The engine idle is incorrect
    • The manifold vacuum at idle is more than 15 inches Hg
    • Refer to Symptoms .
  3. Install the scan tool.
  4. Start the engine.
  5. Display the MAP sensor voltage.

Is the voltage more than the specified value?

4.4 V

Go to DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

Go to Step 3

3
  1. Disconnect the MAP sensor harness connector.
  2. Inspect the MAP sensor harness connector and the terminals.

Did you find a problem?

--

Go to Step 6

Go to Step 4

4
  1. Disconnect the VCM connector C2 and connector C3.
  2. Inspect the terminals and connectors.

Did you find a problem?

--

Go to Step 6

Go to Step 5

5

  1. Reconnect the VCM harness connector and the MAP sensor harness connector.
  2. Start the engine.
  3. Check for an open or a short to voltage in the MAP sensor signal circuit or MAP sensor ground circuit while moving the harness in various locations.
  4. Display the MAP sensor voltage while moving the harness.

Did the voltage fluctuate more than the specified value?

0.5 V

Go to Step 6

Go to Diagnostic Aids

6

Repair the circuit as necessary. Refer to Wiring Repairs or to Connector Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 7

--

7
  1. Using the scan tool, clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle until the engine reaches a normal operating temperature.
  4. Select the DTC and the Specific DTC functions.
  5. Enter the DTC number which was set.
  6. Operate the vehicle within the Conditions for Setting the DTC until the scan tool indicates the diagnostic Ran.

Does the scan tool indicate the diagnostic Passed?

--

Go to Step 8

Go to Step 2

8

Does the scan tool display any additional undiagnosed DTCs?

--

Go to the applicable DTC table

System OK