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 linear 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 signal for voltages outside the normal range of the MAP sensor. If the PCM detects a MAP signal voltage that is intermittently low, DTC P1107 will be set.
Conditions for Setting the DTC
| • | No TP sensor DTC(s) are present. |
| • | Ignition ON. |
| • | Throttle angle is steady above 5% if engine speed is above 1000 RPM. |
| • | The MAP sensor indicates an intermittent manifold absolute pressure below 2 kPa. |
| • | Above conditions for over 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A 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 Clear Info function. |
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. |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic system Check performed? | -- | Go to Powertrain OBD System Check | |||||||
2 | Select DTC info, Last Test Fail and note any other DTCs set. Is DTC P0107 also set? | -- | Go to other DTC chart first | |||||||
3 | Is DTC P1122 also set? | -- | ||||||||
4 | Check for a poor 5 volt reference A circuit or MAP signal circuit terminal connection at the MAP sensor. Was a problem found? | -- | ||||||||
5 | Check the MAP signal circuit between the MAP sensor connector and the PCM for an intermittent open or short to ground (refer to Engine Electrical). Was a problem found? | -- | ||||||||
6 | Check for an intermittent short to ground on the 5 volt reference A circuit between the PCM and the following components (refer to Engine Electrical):
Was a problem found? | -- | ||||||||
7 | Check for a poor 5 volt reference A terminal connection at the PCM (refer to Engine Electrical). Was a problem found? | -- | ||||||||
8 | Check for an intermittent open or a faulty splice in the 5 volt reference A circuit (refer to Engine Electrical). Was a problem found? | -- | Refer to Diagnostic Aids | |||||||
9 | Replace the faulty harness connector terminal(s) for the 5 volt reference A circuit and/or the MAP signal circuit as necessary (refer to Engine Electrical). Is action complete? | -- | -- | |||||||
10 | Repair intermittent open/short circuit in wiring harness as necessary (refer to Engine Electrical). Is action complete? | -- | -- | |||||||
11 |
Does scan tool indicate DTC P1107 failed? | -- | Repair complete |
