The manifold absolute pressure (MAP) sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) supplies 5V to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a voltage signal to the ECM on the signal circuit relative to the intake manifold pressure changes.

The sensor used on this engine is a three atmosphere sensor. Pressure in the intake manifold is affected by engine speed, throttle opening, turbocharger boost pressure, intake air temperature (IAT), and barometric pressure (BARO). Under normal operation the greatest pressure that can exist in the intake manifold at ignition ON, engine OFF is equal to the BARO. When the vehicle is operated at wide-open throttle (WOT), the turbocharger can increase the pressure to near 240 kPa. The least manifold pressure occurs when the vehicle is decelerating and can range from 13-48 kPa.

The purpose of this diagnostic is to analyze the performance of the MAP sensor by comparing the measured pressure changes to the following 2 distinct models:

P0106 - Engine Cranking

P0106 - Engine Running

P0106 - Engine Cranking

The ECM detects when the engine is cranking that the MAP sensor signal plus a calibrated threshold is not within range of a model derived from BARO, and boost pressure for more than 2 seconds.

P0106 - Engine Running

DTC P0106 is a Type B DTC.

DTC P0106 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

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. Verify that DTCs P0641, P0642, or P0643 are not set.

⇒	If any of the DTCs are set, refer to DTC P0641-P0643, P0651-P0653, or P0697-P0699.

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.
4. Ignition OFF for 90 seconds, determine the current vehicle testing altitude.
5. Ignition ON, engine OFF, observe the scan tool BARO parameter, Boost Pressure Sensor parameter, and MAP Sensor parameter. Compare the parameters to the Altitude Versus Barometric Pressure table. The parameters should be within the specified range indicated in the table.
6. Ignition ON, observe the scan tool MAP Sensor parameter. Start the engine. The MAP Sensor parameter should change.
7. Use the scan tool and compare the MAP Sensor parameter to the Boost Pressure Sensor parameter during a WOT acceleration at the time of the 1-2 shift. The readings should be within 20 kPa of each other.
8. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Verify the integrity of the entire air induction system including all turbocharger components by inspecting for the following conditions:

•	Any damaged components

•	Loose or improper installation including the flexible ductwork of the turbocharger and the CAC

•	An air flow restriction

•	Any vacuum leak

•	In cold climates, inspect for any snow or ice buildup at the BARO port on the K20 ECM

•	A restriction in the MAP sensor port or the BARO port

2. Ignition OFF, disconnect the harness connector at the B74 MAP sensor.
3. Ignition OFF for 90 seconds, test for less than 5Ω between the low reference circuit terminal 2 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 K20 ECM.

4. Ignition ON, test for 4.8-5.2V between the 5-volt reference circuit terminal 1 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 K20 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 K20 ECM.

5. Verify the scan tool MAP Sensor parameter is less than 1 kPa.

⇒	If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the K20 ECM.

6. Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 1. Verify the scan tool MAP Sensor parameter is greater than 254 kPa.

⇒	If less than the specified range, test the signal circuit terminal 3 for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

7. If the circuits test normal, test or replace the B74 MAP sensor.

Note: 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.

THEN

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 B74 MAP sensor.
2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal 1 and the corresponding terminal of the MAP sensor.
3. Install a jumper wire between the low reference circuit terminal 2 of the MAP sensor and ground.
4. Install a jumper wire at terminal 3 of the MAP sensor.
5. Connect a DMM between the jumper wire from terminal 3 of the MAP sensor and ground.
6. Ignition ON, with the J 23738-A or the J 35555 , slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5.2V, without any spikes or dropouts.

⇒	If the voltage reading is erratic, replace the B74 MAP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.