GM Service Manual Online
For 1990-2009 cars only

Object Number: 412824  Size: SF
Engine Controls Components
Cell 21: EVAP and EGR Controls
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure (vacuum). The MAP sensor signal voltage to the PCM varies from below 2 volts at idle (high vacuum) to above 4 volts with the key ON, engine not running or at wide open throttle (low vacuum).

The MAP sensor is used to determine manifold pressure changes while the EGR flow test diagnostic is being run (refer to DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient ), to determine engine vacuum level for some other diagnostics and to determine barometric pressure (BARO). The PCM monitors the MAP signals for voltages outside the normal range of the MAP sensor. If the PCM detects a MAP signal voltage that is excessively low, DTC P0107 will be set.

Conditions for Running the DTC

    •  No TP sensor DTCs present.
    •  Engine running.
    •  System voltage greater than 9.0 volts.
    •  Throttle angle above 10%, if engine speed is above 1000 RPM.

Conditions for Setting the DTC

    •  The MAP sensor signal is less than 12.1 kPa.
    • The above conditions have been met for greater than 2 seconds.

Action Taken When the DTC Sets

    • The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecuitive trip in which the diagnostic has been run and failed.
    • If equipped with traction control, the PCM will command the EBTCM via the serial data circuit to turn OFF traction control, and the EBTCM will illuminate the TRACTION OFF lamp.
    • The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

Conditions for Clearing the MIL/DTC

    • The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
    • The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool.

Diagnostic Aids

Check for the following conditions:

    •  Monitor the MAP sensor using the scan tool. If the MAP sensor does not respond to throttle changes, check the 3X reference circuits from the ignition control module to the PCM.
         If the 3X reference signal is lost the PCM will only update the MAP sensor reading once per key cycle, when the engine is first started.
         Depending on where the MAP sensor voltage (high voltage or low voltage) is when the engine is started, the high or low voltage MAP sensor DTCs will set.
    •  Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems.
    •  Damaged harness. 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. Refer to Wiring Repairs in Wiring Systems.

If DTC P0107 cannot be duplicated, the information included in the Fail Records data can be useful in determining the conditions that caused this DTC to set. If it is determined that the DTC occurs intermittently, performing the DTC P1107 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent Low Voltage Diagnostic Table may isolate the cause of the fault.

Step

Action

Value(s)

Yes

No

1

Was the Powertrain OBD System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn the ignition on, and leave the engine off.
  2. With the throttle closed, observe the MAP value displayed on the scan tool engine data list.

Is MAP value near the specified value?

0.0 volt

Go to Step 4

Go to Step 3

3

  1. Ensure the ignition is on, and the engine is off.
  2. Review and record scan tool Fail Records data.
  3. Operate vehicle within Fail Records conditions as noted.
  4. Using a scan tool, monitor Specific DTC info for DTC P0107.

Does scan tool indicate DTC P0107 failed?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Disconnect the MAP sensor electrical connector.
  2. Jumper the 5 Volt Reference A circuit and the MAP signal circuit together at the MAP sensor harness connector.
  3. Observe the MAP value displayed on the scan tool.

Is MAP value near the specified value?

4.95V

Go to Step 10

Go to Step 5

5

  1. Remove the jumper.
  2. Connect a J 35616-200 test lamp between battery positive voltage and the MAP sensor signal circuit at the MAP sensor harness connector.
  3. Observe the MAP value displayed on the scan tool.

Is MAP value near the specified value?

4.95V

Go to Step 6

Go to Step 8

6

  1. Turn the ignition off.
  2. Disconnect the PCM and check the 5 Volt Reference A circuit for an open or short to ground.
  3. If the 5 Volt Reference A circuit is open or shorted to ground, repair it as necessary. Refer to Wiring Repairs in Wiring Systems..

Was the 5 volt reference A circuit open or shorted to ground?

--

Go to Step 12

Go to Step 7

7

Test the 5 volt reference A circuit for a poor connection at the PCM and replace terminal if necessary. Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals , and Connector Repairs in Wiring Systems..

Did the terminal require replacement?

--

Go to Step 12

Go to Step 11

8

  1. Turn the ignition off.
  2. Disconnect the PCM.
  3. Test the MAP Sensor signal circuit for an open, short to ground, or short to the sensor ground.
  4. If the MAP sensor signal circuit is open or shorted to ground, repair it as necessary. Refer to Wiring Repairs in Wiring Systems..

Was the MAP signal circuit open or shorted to ground?

--

Go to Step 12

Go to Step 9

9

Test the MAP sensor signal circuit for a poor connection at the PCM and replace terminal if necessary. Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals , and Connector Repairs in Wiring Systems..

Did the terminal require replacement?

--

Go to Step 12

Go to Step 11

10

Replace the MAP sensor. Refer to MAP Sensor Replacement .

Is the action complete?

--

Go to Step 12

--

11

Important: :  Replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM.

Is the action complete?

--

Go to Step 12

--

12

  1. Turn the ignition on, and leave the engine off.
  2. Clear the DTCs.
  3. Operate vehicle within Fail Records conditions as noted.
  4. Using a scan tool, monitor Specific DTC info for DTC P0107.

Does scan tool indicate DTC P0107 failed?

--

Go to Step 2

System OK