GM Service Manual Online
For 1990-2009 cars only

Object Number: 12257  Size: MF
Engine Controls Components
PCM MAP, TP, ECT, IAT, and A/C Pressure Switch
OBD II Symbol Description Notice
Handling ESD Sensitive Parts 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), 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 Setting the DTC

    • No TP sensor DTCs present.
    • The engine is running.
    • Throttle angle greater than 0%, if engine speed is less than 1000 RPM.
    • Throttle angle greater than 6%, if engine speed is greater than 1000 RPM.
    • The MAP sensor signal voltage is less than 0.1 volt.
    • The above conditions present for at least 200 3X reference periods (67 crankshaft revolutions).

Action Taken When the DTC Sets

    • The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
    • 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:

    • Poor connection at the PCM--Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
    • 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 malfunction.

If DTC P0107 cannot be duplicated, the information included in the Failure Records data can be useful in determining since the DTC was last set. If it is determined that the DTC occurs intermittently, performing the DTC P1107 Diagnostic Chart may isolate the cause of the malfunction.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table:

  1. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

DTC P0107 - MAP Sensor Circuit Low Voltage

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to the Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn ON the ignition switch.
  2. Observe the MAP value displayed on the scan tool.

Is MAP value near the specified value?

0V

Go to Step 4

Go to Step 3

3

  1. Turn ON the ignition switch.
  2. Review and record scan tool Fail Records data.
  3. Operate the vehicle within Fail Records conditions.
  4. Using a scan tool, monitor Specific DTC info for DTC P0107.

Does the 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 together at the MAP sensor harness connector.
  3. Observe the MAP value displayed on the scan tool.

Is the MAP value greater than the specified value?

4.6V

Go to Step 10

Go to Step 5

5

  1. Connect a test light between B+ and the MAP sensor signal circuit at the MAP sensor harness connector.
  2. Observe the MAP value displayed on the scan tool.

Is the MAP value near the specified value?

4.6V

Go to Step 6

Go to Step 8

6

  1. Turn OFF the ignition switch.
  2. Disconnect the PCM.
  3. Check the 5 volt reference A circuit for an open, short to ground, or short to the sensor ground circuit.
  4. If a problem is found, repair it as necessary. Refer to Repair Procedures in Electrical Diagnosis.

Was a problem found?

--

Go to Step 12

Go to Step 7

7

  1. Check the 5 volt reference A circuit for a poor connection at the PCM.
  2. If a problem is found, repair as necessary. Refer to Repair Procedures in Electrical Diagnosis.

Was a problem found?

--

Go to Step 12

Go to Step 11

8

  1. Turn OFF the ignition switch.
  2. Disconnect the PCM.
  3. Check the MAP signal circuit for an open, short to ground, or short to the sensor ground circuit.
  4. If a problem is found, repair as necessary. Refer to Repair Procedures in Electrical Diagnosis.

Was a problem found?

--

Go to Step 12

Go to Step 9

9

  1. Check the MAP sensor signal circuit for a poor connection at the PCM.
  2. If a problem is found, repair as necessary. Refer to Repair Procedures in Electrical Diagnosis.

Was a problem found?

--

Go to Step 12

Go to Step 11

10

Replace the MAP sensor.

Is action complete?

--

Go to Step 12

--

11

Replace the PCM.

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

Is action complete?

--

Go to Step 1

--

12

  1. Turn ON the ignition switch.
  2. Review and record scan tool Fail Records data.
  3. Clear DTCs.
  4. Operate the vehicle within Fail Records conditions.
  5. Using a scan tool, monitor Specific DTC info for DTC P0107.

Does the scan tool indicate DTC P0107 failed?

--

Go to Step 4

System OK