Circuit Description
The Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure (vacuum). The MAP sensor signal voltage to the PCM varies from below 2 volts at idle (high vacuum) to above 4 volts with the key on, engine not running or at wide-open throttle (low vacuum). The MAP sensor is used to determine manifold pressure changes while the EGR flow test diagnostic is being run (refer to DTC P0401), to determine engine vacuum level for some other diagnostics and to determine barometric pressure (BARO). The PCM monitors the MAP signals for voltages outside the normal range of the MAP sensor. If the PCM detects a MAP signal voltage that is excessively low, DTC P0107 will be set.
Conditions for Setting the DTC
| • | No TP sensor DTCs present. |
| • | The engine is running. |
| • | Throttle angle above 0%, if engine speed is less than 1000 rpm. |
| • | Throttle angle above 6%, if engine speed is greater than 1000 rpm. |
| • | The MAP sensor signal voltage is less than 0.1 volt. |
| • | Above conditions present for longer than 175 3X reference periods (58 crankshaft revolutions). |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed. |
| • | The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool. |
Diagnostic Aids
Check for the following conditions:
| • | Monitor the MAP sensor using the scan tool. If the MAP sensor does not respond to throttle changes, check the 3X circuits from the ignition control module to the PCM. |
| If the 3X signal is lost the PCM will only update the MAP sensor reading once per key cycle, when the engine is first started. |
| Depending on where the MAP sensor voltage (high voltage or low voltage) is when the engine is started, the high or low voltage MAP sensor DTC's will set. |
| • | Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the MAP display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault. |
If DTC P0107 cannot be duplicated, the information included in the Fail Records data can be useful in determining since the DTC was last set. If it is determined that the DTC occurs intermittently, performing DTC P1107 Diagnosis may isolate the cause of the fault.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table:
-
This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On Board Diagnostic (OBD) System Check performed? | -- | ||
2 |
Is MAP value near the specified value? | 0 V | ||
3 |
Does scan tool indicate DTC P0107 failed? | -- | Refer to Diagnostic Aids | |
4 |
Is MAP value near the specified value? | 4.95 V | ||
5 |
Is MAP value near the specified value? | 4.95 V | ||
6 |
Was a problem found? | -- | ||
7 | Check the 5 Volt reference A circuit for a poor connection at the PCM and replace terminal if necessary. Refer to Repair Procedures in Electrical Diagnosis. Was a problem found? | -- | ||
8 |
Was a problem found? | -- | ||
9 | Check the MAP sensor signal circuit for a poor connection at the PCM and replace terminal if necessary. Refer to Repair Procedures in Electrical Diagnosis. Was a problem found | -- | ||
10 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement Is the action complete? | -- | -- | |
Replace the PCM. Important: : The replacement PCM must be programmed. Go to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||
12 |
Using a scan tool, monitor Specific DTC info for DTC P0107. Does the scan tool indicate DTC P0107 failed? | -- | System OK |
