Circuit Description
The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature, and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on the 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.
Under normal operation the highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor in order to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 19 kPa when pressures are low, to as much as 104 kPa when pressures are high, depending on the BARO.
Within the ECM, the diagnostic has the ability to determine an inaccurate input from the MAP sensor. Calibrated within the diagnostics are estimates for MAP based on throttle position and engine speed. the diagnostic compares the estimated value to the actual sensor input. If the ECM detects that the MAP sensor input is not within a calibrated limit of the estimated value, DTC P0106 sets.
Conditions for Running the DTC
| • | DTC P0068, P0101, P0102, P0103, P0107, P0108, P0122, P0123, P0222, P0223, P0506, P0507, P2101, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2138, or P2176 are not set. |
| • | The engine speed is between 600-6,300 RPM. |
Conditions for Setting the DTC
The ECM detects that the MAP sensor pressure is not within a calibrated limit of the estimated value for more than 1 second.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||
2 |
Is DTC P2095 also set? | -- | Go to Step 3 | |||||||||
3 |
Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 4 | ||||||||
4 |
Important: The vehicle used for the comparison is not limited to the same type of vehicle as is being serviced. A vehicle known to provide an accurate reading is acceptable. Do you have access to another vehicle in which the MAP sensor pressure can be observed with a scan tool? | -- | Go to Step 5 | Go to Step 6 | ||||||||
Is the difference between the values less than the specified value? | 3 kPa | Go to Step 7 | Go to Step 12 | |||||||||
6 |
Important: The Altitude vs. Barometric Pressure table indicates a pressure range for a given altitude under normal weather conditions. Weather conditions consisting of very low or very high pressure and/or very low or very high temperature may cause a reading to be slightly out of range.
Does the MAP sensor indicate the correct barometric pressure? | -- | Go to Step 7 | Go to Step 12 | ||||||||
7 |
Does the MAP sensor pressure change? | -- | Go to Step 8 | Go to Step 12 | ||||||||
8 |
Is the decrease in MAP sensor pressure consistent? | -- | Go to Step 9 | Go to Step 12 | ||||||||
9 | Apply vacuum with the J 23738-A until 20 in Hg is reached. Is the MAP sensor pressure less than the specified value? | 34 kPa | Go to Step 10 | Go to Step 12 | ||||||||
10 | Disconnect the J 23738-A from the MAP sensor. Does the MAP sensor pressure return to the value observed in step 4 or 5? | -- | Go to Step 11 | Go to Step 28 | ||||||||
11 | Inspect for the following conditions:
Did you find and correct the condition? | -- | Go to Step 30 | Go to Intermittent Conditions | ||||||||
12 | Test for an intermittent and for a poor connection at the MAP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 13 | ||||||||
13 |
Is the pressure less than the specified value? | 20 kPa | Go to Step 14 | Go to Step 20 | ||||||||
Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Note the measurement as Supply voltage. Is the voltage more than the specified value? | 5.2 V | Go to Step 21 | Go to Step 15 | |||||||||
15 | Is the voltage more than the specified value? | 4.8 V | Go to Step 16 | Go to Step 22 | ||||||||
16 |
Is the amperage equal to the specified value? | 0 mA | Go to Step 25 | Go to Step 17 | ||||||||
Important: Before any calculations are performed, ensure that all measurements are converted into like units, for example volts/amps or millivolts/milliamps. Is the result more than the specified value? | 5 ohms | Go to Step 23 | Go to Step 18 | |||||||||
Important: Before any calculations are performed, ensure that all measurements are converted into like units, for example volts/amps or millivolts/milliamps. Is the result more than the specified value? | 5 ohms | Go to Step 26 | Go to Step 19 | |||||||||
19 |
Is the pressure more than the specified value? | 103 kPa | Go to Step 28 | Go to Step 24 | ||||||||
20 | Test the MAP sensor signal circuit between the engine control module (ECM) and the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 27 | ||||||||
21 | Test all branches of the 5-volt reference circuit that are shared with the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 27 | ||||||||
22 | Test the 5-volt reference circuit between the ECM and the MAP sensor for an open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 27 | ||||||||
23 | Test the 5-volt reference circuit between the ECM and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 27 | ||||||||
24 | Test the MAP sensor signal circuit between the ECM and the MAP sensor for the following:
Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 27 | ||||||||
25 | Test the low reference circuit between the ECM and the MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 27 | ||||||||
26 | Test the low reference circuit between the ECM and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 27 | ||||||||
27 | Test for shorted terminals and for poor connections at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 29 | ||||||||
28 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 30 | -- | ||||||||
29 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 30 | -- | ||||||||
30 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 31 | ||||||||
31 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
