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 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.

The engine control module (ECM) 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.

DTC P0106 is a Type B DTC.

DTC P0106 is a Type B DTC.

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

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. If DTC P0641 or P0651 are set, refer to DTC P0641 or P0651.
2. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust.
3. Verify that the engine is in good mechanical condition. Refer to Symptoms - Engine Mechanical for the 4.8L, 5.3L, 6.0L and 6.2L engine.
4. Ignition OFF for 90 seconds, determine the current vehicle testing altitude. Ignition ON, observe the scan tool BARO Sensor parameter. Compare the parameter to the Altitude Versus Barometric Pressuretable. The BARO sensor pressure 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. The readings should be within 3 kPa of the known good vehicle.
6. Ignition ON, observe the scan tool MAP sensor parameter. Start the engine. The MAP Sensor parameter should change.

⇒	If the vehicle passes the Circuit System Verification Test, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records list.

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

1. Verify the integrity of the air induction system by inspecting for the following conditions:

•	Any damaged components

•	Loose or improper installation

•	Improperly routed vacuum hoses

•	Any vacuum leak

•	Any type of restriction

•	MAP sensor seal that is missing or damaged

2. Verify that restrictions do not exist in the MAP sensor vacuum source.
3. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust.
4. Ignition OFF, disconnect the MAP harness connector at the MAP sensor.
5. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal A and ground.

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

6. 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.

7. 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.

8. Install a 3A 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.

⇒	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.

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

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.

Skewed Sensor Test

1. Using the following steps and referencing the table below will determine if the MAP sensor is skewed.
2. Ignition ON, engine OFF, observe the MAP sensor scan tool parameter.
3. Use the observed MAP Sensor Scan Tool parameter that is closest to a value that is indicated in the first column.
4. Using the J 23738-A or the J 35555 to apply 5 in Hg of vacuum to the MAP sensor, the parameter in the first column should decrease by 17 kPa. The acceptable range is indicated in the second column.
5. Using the J 23738-A or the J 35555 to apply 10 in Hg of vacuum to the MAP sensor, the parameter in the first column should decrease by 34 kPa. The acceptable range is indicated in the third column.

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 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 the terminal B of the MAP sensor and ground.
6. Ignition ON, with the J 23738-A or J 35555 , slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 4.9-0.2 volts without any spikes or dropouts.

⇒	If the voltage is erratic, replace the MAP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.