Circuit Description
Without Supercharger/RPO L26
The manifold absolute pressure (MAP) sensor responds to changes in the intake manifold pressure, which gives an indication of the engine load. The MAP sensor wiring includes a 5-volt reference circuit, a low reference circuit, and a signal circuit. The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit, which is relative to the pressure changes in the manifold. With low MAP, such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP, such as during ignition ON, engine OFF or wide open throttle (WOT), the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 10-104 kPa. The MAP sensor is also used in order to calculate the barometric pressure (BARO) when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at wide-open throttle. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is excessively high, DTC P0108 sets.
With Supercharger/RPO L32
The MAP sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor wiring includes a 5-volt reference circuit, a low reference circuit, and a signal circuit. The PCM supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit, which is relative to the pressure changes in the manifold. With low MAP, such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP, such as WOT, the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 8-208 kPa. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is excessively high, DTC P0108 sets.
Conditions for Running the DTC
| • | DTCs P0068, P0120, P0220, P1125, P1516, P1518, P2101, P2107, P2108, P2119, P2120, P2125, P2135, P2138 are not set. |
| • | The engine has been running for a length of time that is determined by the start-up coolant temperature. The length of time ranges from 2 minutes at less than -30°C (-22°F) to 1 second at more than 30°C (86°F). |
| • | The throttle angle is less than 2 percent when engine speed is less than 1,000 RPM. |
| OR |
| • | The throttle angle is less than 10 percent when the engine speed is more than 1,000 RPM. |
Conditions for Setting the DTC
The PCM detects that the MAP sensor signal voltage is more than 4.3 volts for 7 seconds.
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 numbers below refer to the step numbers on the diagnostic table.
-
The MAP sensor, the exhaust gas recirculation (EGR) valve, and the fuel tank pressure (FTP) sensor utilize the 5-volt reference A circuit for supply voltage. DTC P0641 sets if a failure occurs causing this system voltage to be pulled high or low. This DTC should be diagnosed first.
-
A short to voltage on the MAP sensor signal circuit may backfeed through the sensor affecting the 5-volt reference system voltage. This step tests for this condition.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |||||||
2 |
Is the voltage more than the specified value? | 4.3 V | Go to Step 4 | Go to Step 3 | ||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions | ||||||
4 | Inspect the MAP sensor vacuum source for the following conditions:
Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 5 | ||||||
Monitor the DTC information with the scan tool. Is DTC P0641 also set? | -- | Go to Step 9 | Go to Step 6 | |||||||
6 | 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 15 | Go to Step 7 | ||||||
7 |
Is the voltage less than the specified value? | 0.1 V | Go to Step 8 | Go to Step 10 | ||||||
8 |
Is the voltage more than the specified value? | 0.2 V | Go to Step 11 | Go to Step 13 | ||||||
Is the voltage less than the specified value? | 0.1 V | Go to DTC P0641 | Go to Step 10 | |||||||
10 |
Important: Disconnecting the powertrain control module (PCM) may eliminate the short during testing. Important: The MAP sensor may have been damaged if the circuit was shorted to a voltage source. Test the MAP sensor signal circuit between the PCM 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 15 | Go to Step 14 | ||||||
11 | Test the low reference circuit between the PCM and the MAP sensor for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 | ||||||
12 | Test for an intermittent and for a poor connection at the PCM. 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 15 | Go to Step 14 | ||||||
13 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||
14 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||
15 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 16 | ||||||
16 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||
