For 1990-2009 cars

### 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, P0340, P0365, P0452, P0532, P0641 | P0106, P0107 | P0107 | P0108, P0340, P0365, P0453, P0533, P0641 | 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 | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Engine Running Parameter Normal Range: 12-103 kPa
5-Volt Reference | 10 kPa | 10 kPa | 104 kPa
MAP Sensor Signal | 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 from this model is displayed on the scan tool as the MAF Performance Test parameter.

• | 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 from this model is displayed on the scan tool as the MAP Performance Test 1 parameter.

• | 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 from this model is displayed on the scan tool as the MAP Performance Test 2 parameter.

• | The fourth model is created from the combination and additional calculations of the throttle model and the first intake manifold model. The information from this model is displayed on the scan tool as the TP Performance Test parameter.

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.

#### Scan Tool Diagnostic Test Results

MAF Performance Test | MAP Performance Test 1 | MAP Performance Test 2 | TP Performance Test | DTCs Passed | DTCs Failed
--- | --- | --- | --- | --- | ---
-- | -- | 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
-- | -- | OK | Fault | P0101, P0106, P1101 | P0121
OK | OK | Fault | Fault | P0101, P0106, P0121, P1101 | None
Fault | OK | Fault | Fault | P0101, P0106, P0121 | P1101
-- | 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°C to +125°C (+19°F 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 ECM detects that the actual measured airflow from MAF, MAP, and TP is not within range of the calculated airflow that is derived from the system of models for more than 2 seconds.

### 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 .

• | The barometric pressure (BARO) that is used by the 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.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Controls Connector End Views

• | Engine 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

#### Special Tools Required

• | J 23738-A Mityvac

• | J 35555 Metal Mityvac

### Circuit/System Verification

1. If DTC P0641 or P0651 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
2. Verify that the engine is in good mechanical condition. Refer to Symptoms - Engine Mechanical .
3. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust .
4. Ignition OFF for 90 seconds, determine the current vehicle testing altitude. Ignition ON, observe the scan tool BARO parameter. Compare the parameter to the Altitude Versus Barometric Pressure table. The BARO parameter should be within the specified range indicated in the table.
5. 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

1. 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

2. Verify that restrictions do not exist in the MAP sensor port or vacuum source.
3. Ignition OFF, disconnect the MAP harness connector at the MAP sensor.
4. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal A and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

5. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.

⇒ | 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 ECM.

⇒ | 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.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

7. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit terminal C. Verify the scan tool MAP Sensor parameter is greater than 103 kPa.

⇒ | 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 ECM.

8. If all circuits test normal, test or replace the MAP sensor.

### Component Testing

#### Skewed Signal Test

1. Ignition OFF, remove the vacuum source from the MAP sensor.
2. Ignition ON, observe and recorded the scan tool MAP Sensor parameter. This is the first MAP sensor reading.
3. With the J 23738-A or J 35555 , apply 5 in Hg (17 kPa) of vacuum to the MAP sensor. Observe and record the scan tool MAP Sensor parameter. This is the second MAP sensor reading.
4. Subtract the second MAP sensor reading from the first MAP sensor reading. Verify that the vacuum decrease is within 1 in Hg (4 kPa) of the applied vacuum.

⇒ | If the vacuum decrease is not within the specified range, replace the MAP sensor.

5. With the J 23738-A or J 35555 , apply 10 in Hg (34 kPa) of vacuum to the MAP sensor. Observe and record the scan tool MAP Sensor parameter. This is the third MAP sensor reading.
6. Subtract the third MAP sensor reading from the first MAP sensor reading. Verify that the vacuum decrease is within 1 in Hg (4 kPa) of the applied vacuum.

⇒ | If the vacuum is not within the specified range, replace the MAP sensor.

#### Erratic Signal Test

1. Ignition OFF, remove the MAP sensor.
2. Install a 3A 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. Ignition ON, install the J 23738-A or 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.

⇒ | If the voltage reading 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 ECM replacement, setup, and programming