GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    •  Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0106: Manifold Absolute Pressure (MAP) Sensor Performance

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

5-Volt Reference

P0107, P0222, P0651, P2122

P0106, P0107

P0107

P0106, P0108, P0223, P0651, P2123

P0106, P0107

MAP Sensor Signal

P0107

P0106, P0107

P0107

P0108

P0106, P0107, P1101

Low Reference

--

P0106, P0108

P0106, P0108

--

P0106, P0108

Typical Scan Tool Data

MAP Sensor

Circuit

Normal Range

Short to Ground

Open

Short to Voltage

5-Volt Reference

--

10 kPa

10 kPa

104 kPa

MAP Sensor Signal

12-103 kPa

10 kPa

10 kPa

104 kPa

Low Reference

--

--

80-103 kPa

--

Circuit Description

The intake flow rationality diagnostic provides the within-range rationality check for the mass air flow (MAF), manifold absolute pressure (MAP), and the throttle position (TP) sensors. This is an explicit model-based diagnostic containing 4 separate models for the intake system.

    • The throttle model describes the flow through the throttle body and is used to estimate the MAF through the throttle body as a function of barometric pressure (BARO), TP, intake air temperature (IAT), and estimated MAP. The information derived from this model is the MAF Performance Test.
    • The first intake manifold model describes the intake manifold and is used to estimate MAP as a function of the MAF into the manifold from the throttle body and the MAF out of the manifold caused by engine pumping. The flow into the manifold from the throttle uses the MAF estimate calculated from the above throttle model. The information derived from this model is the MAP Performance Test 1.
    • The second intake manifold model is identical to the first intake manifold model except that the MAF sensor measurement is used instead of the throttle model estimate for the throttle air input. The information derived from this model is the MAP Performance Test 2.
    • The fourth model is created from the combination and additional calculations of the throttle model and the first intake manifold model. The information derived from this model is the TP Performance Test.

The estimates of MAF and MAP obtained from this system of models and calculations are then compared to the actual measured values from the MAF, MAP, and the TP sensors and to each other to determine the appropriate DTC to fail. The following table illustrates the possible failure combinations and the resulting DTC or DTCs.

MAF Performance Test

MAP Performance Test 1

MAP Performance Test 2

TP Performance Test

DTCs Passed

DTCs Failed

X

X

OK

OK

P0101, P0106, P0121, P1101

None

OK

OK

Fault

OK

P0101, P0106, P0121, P1101

None

Fault

OK

Fault

OK

P0106, P0121, P1101

P0101

OK

Fault

Fault

OK

P0101, P0121, P1101

P0106

Fault

Fault

Fault

OK

P0121, P1101

P0101, P0106

X

X

OK

Fault

P0101, P0106, P1101

P0121

OK

OK

Fault

Fault

P0101, P0106, P0121, P1101

None

Fault

OK

Fault

Fault

P0101, P0106, P0121

P1101

X

Fault

Fault

Fault

P0101, P0106, P0121

P1101

Conditions for Running the DTC

    • DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0128, P0335, P0336 are not set.
    • The engine speed is between 400-8,192 RPM.
    • The IAT Sensor parameter is between -7 to +125°C (+19 to 257°F).
    • The ECT Sensor parameter is between 70-125°C (158-257°F).
    • This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTC

The powertrain control module (PCM) detects that the MAP sensor pressure is not within range of the calculated pressure that is derived from the system of models for more than 0.5 second.

Action Taken When the DTC Sets

DTC P0106 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P0106 is a Type B DTC.

Diagnostic Aids

    • A wide open throttle (WOT) acceleration from a stop should cause the MAP sensor parameter on the scan tool to increase rapidly to near the BARO Sensor parameter at the time of the 1-2 shift.
    • A skewed or stuck engine coolant temperature (ECT) sensor or IAT sensor will cause the calculated models to be inaccurate and may cause this DTC to run when it should not. Refer to Temperature Versus Resistance .

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Controls Connector End Views
    •  Powertrain Control Module Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Output Controls
    •  Scan Tool Snapshot Procedure

Circuit/System Verification

Important: Verify that the engine is in good mechanical condition before continuing with this diagnostic.

    • If DTC P0641 or P0651 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
    • Verify the integrity of the entire air induction system by inspecting for the following conditions:
       - Any damaged components
       - Loose or improper installation
       - An air flow restriction
       - Any vacuum leak
       - Improperly routed vacuum hoses
       - In cold climates, inspect for any snow or ice buildup
    • Verify that restrictions do not exist in the MAP sensor port or vacuum source.
    • Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust .
    • The BARO that is used by the engine control module (ECM) to calculate the air flow models is initially based on the MAP sensor at ignition ON. When the engine is running, the ECM will continually update the BARO value near WOT using the MAP sensor and a calculation. A skewed MAP sensor will cause the BARO value to be inaccurate. Determine the current vehicle testing altitude. Ignition ON, observe the scan tool BARO Sensor parameter. Compare the parameter to the Altitude vs Barometric Pressure table. Refer to Altitude Versus Barometric Pressure .
    • A skewed MAP sensor will also cause the first and second intake manifold models to disagree with the actual MAP sensor measurements. Use the scan tool and compare the MAP Sensor parameter to a known good vehicle, under various operating conditions.

Circuit/System Testing

    Important: All electrical components and accessories must be turned OFF, and allowed to power down.

  1. Ignition OFF, disconnect the MAP harness connector at the MAP sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal A and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.
  5. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM.
    If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Verify the scan tool MAP Sensor parameter is less than 12 kPa.
  7. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the PCM.
  8. Install a 3-amp fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify the scan tool MAP Sensor parameter is greater than 103 kPa.
  9. If less than the specified range, test the signal circuit terminal B for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM.
  10. If all circuits test normal, test the MAP sensor. Refer to Component Testing for instructions.

Component Testing

    Important: You must perform the Circuit/System Testing in order to verify the integrity of the MAP sensor circuits before proceeding with the Component Testing.

  1. Ignition ON, remove the MAP sensor.
  2. Install a 3-amp fused jumper wire between the 5-volt reference circuit terminal C and the corresponding terminal of the MAP sensor.
  3. Install a jumper wire between the low reference circuit terminal A of the MAP sensor and ground.
  4. Install a jumper wire at terminal B of the MAP sensor.
  5. Connect a DMM between the jumper wire from terminal B of the MAP sensor and ground.
  6. Install the J 35555 to the MAP sensor vacuum port. Slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5.2 volts, without any spikes or dropouts.
  7. If the voltage is not within the specified range or is erratic, replace the MAP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Manifold Absolute Pressure Sensor Replacement
    •  Control Module References for PCM replacement, setup, and programming