GM Service Manual Online
For 1990-2009 cars only

Object Number: 368491  Size: LF
Engine Controls Components
Cell 20: Engine Controls, Exhaust Gas Recirculation Valve
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The Manifold Absolute Pressure (MAP) sensor is mounted in front of the intake manifold. The MAP sensor measures pressure changes within the intake manifold, which is an indication of engine load. The MAP sensor has a 5.0  volt reference, a ground and a signal circuit. The MAP sensor contains diaphragm which changes resistance based on pressure. When manifold pressure is low (high vacuum) sensor output voltage is low. When manifold pressure is high (low vacuum) sensor output voltage is high. MAP sensor voltage (depending on altitude) can range from 1.0-1.5 volts at idle (high vacuum) to 4.0-4.9 volts at wide open throttle (low vacuum). When the PCM senses a signal voltage lower than the normal operating range of the sensor this DTC will set.

Conditions for Running the DTC

    • No TP sensor DTC are set.
    • The engine is running.
    • TP sensor is greater than 0 percent when engine is less than 800 RPM.
    • TP sensor is greater than 12.5 percent when engine is greater than 800 RPM.

Conditions for Setting the DTC

The following conditions will set the DTC:

The Ignition voltage is between 10 and 11 Volts.

Action Taken When the DTC Sets

    • The PCM turns on the malfunction indicator lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.
    • The PCM will record operating conditions at the time the diagnostic fails. The first time the diagnostic fails, this information will be stored in Failure Records. If the diagnostic reports a failure on the second consecutive drive trip, the operating conditions at the time of failure will be written to Freeze Frame and the Failure record will be updated.
    • The PCM will use TP sensor values to calculate MAP.

Conditions for Clearing the MIL/DTC

       Important: If the last failure was during a non-typical driving condition, the MIL may remain ON longer than 3 drive trips. Review Freeze Frame and Failure Records for the last failure conditions.

    • The PCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.
    • A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (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.
    • A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.
        Use the scan tool Clear Information function.
    • Disconnect the PCM battery feed for 30 seconds.

Diagnostic Aids

    • An intermittent open in the MAP sensor signal circuit or the 5 volt reference circuit will result in a DTC P1107.
    • With the ignition ON and the engine OFF, the manifold pressure is equal to atmospheric pressure with the signal voltage high. The PCM uses this information as an indication of the vehicle's altitude. Comparison of this reading with a known good vehicle using the same sensor is a good way to check accuracy of a suspect sensor. Readings should be the same ±0.4 volts.
    •  An intermittent open in the MAP sensor signal circuit or the 5 volt reference circuit will result in a DTC P1107.
    • The PCM 5.0 volt reference circuits are internally connected within the PCM. If all the MAP sensor circuits check to be OK, inspect all PCM 5.0 volt reference component/circuits for a malfunction.

Refer to Symptoms .

Important: The electrical connector must remain securely fastened.

Important: After removing the MAP sensor from the intake manifold, replace the MAP Sensor to intake manifold seal.

Remove the MAP sensor. Twist the sensor by hand (only) in order to check for intermittent connections. Output changes greater than 0.1 volt indicates a bad connector or connection. If OK, replace sensor.

Test Description

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

  1. This step determines if the malfunction is present.

  2. Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.

  3. If the scan tool displays 5.0 volts, the MAP sensor signal, 5.0 volt reference circuit, and the PCM are OK. For any test that requires probing the PCM or component harness connectors, use the Connector Test Adapter Kit J 35616 . Using this kit will prevent any damage to the harness connector terminals.

  4. If the scan tool displays 5.0 volts, the MAP sensor signal circuit and the PCM are OK. For any test that requires probing the PCM or component harness connectors, use the Connector Test Adapter Kit J 35616 . Using this kit will prevent any damage to the harness connector terminals.

  5. Disconnecting the PCM allows using the DMM J 39200 in order to check the continuity of the circuits. This aids in locating an open or a shorted circuit.

Step

Action

Value(s)

Yes

No

1

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

Monitor the MAP sensor voltage on Engine 1 Data List on the scan tool.

Is the MAP sensor voltage below the specified value?

0.10 V

Go to Step 4

Go to Step 3

3

  1. Turn ON the ignition leaving the engine OFF.
  2. Review the Freeze Frame and/or Failure Records data for this DTC and observe the parameters.
  3. Turn OFF the ignition for 15 seconds.
  4. Start the engine.
  5. Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in the Freeze Frame/Failure Records as possible. Special operating conditions that you need to meet before the PCM will run this diagnostic, where applicable, are listed in Conditions for Running the DTC.
  6. Select the Diagnostic Trouble Code (DTC) option, the Specific DTC option, then enter the DTC number using the scan tool.

Does the scan tool indicate that this diagnostic failed this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn the ignition OFF.
  2. Disconnect the MAP sensor electrical connector.
  3. Turn ON the ignition leaving the engine OFF.
  4. Jumper the 5.0 volt reference circuit and the MAP sensor signal circuit together at the MAP sensor harness connector.
  5. Observe the MAP sensor voltage display on the scan tool.

Is the MAP sensor voltage near the specified value?

5.0 V

Go to Step 10

Go to Step 5

5

  1. Connect a test lamp J 35616-200 between B+ and the MAP sensor signal circuit at the MAP sensor harness connector.
  2. Observe the MAP sensor voltage display on the scan tool.

Is the MAP sensor voltage near the specified value?

5.0 V

Go to Step 6

Go to Step 8

6

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector. Refer to Powertrain Control Module Replacement .
  3. Check the 5.0 volt reference circuit for an open or short to a ground.
  4. If you find the 5.0 volt reference circuit is open or shorted to a ground, repair the circuit as necessary.

Did you find the 5.0 volt reference circuit open or shorted to a ground?

--

Go to Step 12

Go to Step 7

7

  1. Check the 5.0 volt reference circuit for a poor connection at the PCM
  2. Replace the terminal if necessary. Refer to Wiring Repairs

Did the terminal require replacement?

--

Go to Step 12

Go to Step 11

8

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector. Refer to Powertrain Control Module Replacement .
  3. Check the MAP sensor signal circuit for the following:
  4. • Open circuit
    • Short to a ground
    • Short to sensor ground circuit
  5. If you find the MAP sensor signal circuit is open or shorted to a ground, repair the circuit as necessary. Refer to Wiring Repairs

Did you find the MAP sensor signal circuit open or shorted to a ground?

--

Go to Step 12

Go to Step 9

9

Check the MAP sensor signal circuit for a poor connection at the PCM and replace the terminal if necessary. Refer to Wiring Repairs

Did the terminal require replacement?

--

Go to Step 12

Go to Step 11

10

Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement .

Is the action complete?

--

Go to Step 12

--

11

Important:: Reprogram the replacement PCM.

Replace the PCM. Refer to Powertrain Control Module Replacement .

Is the action complete?

--

Go to Step 12

--

12

  1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the scan tool.
  2. Idle the engine at the normal operating temperature.
  3. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test ran and passed?

--

Go to Step 13

Go to Step 2

13

Select the Capture Info option and the Review Info option using the scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to the applicable DTC table

System OK