DTC P1128: Manifold Absolute Pressure (MAP) Sensor Signal Lower Than Expected: General Description
The manifold absolute pressure (MAP) sensor senses manifold absolute pressure (vacuum) and converts it into electrical signals. The MAP sensor outputs low signal voltage at high-vacuum (idling) and high signal voltage at low-vacuum (throttle valve wide open).
The engine control module (ECM) compares a predetermined MAP value at a given throttle position and manifold absolute pressure to the output voltage value of the MAP sensor.
If the MAP sensor outputs lower voltage than expected, the ECM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
| Execution | Once per driving cycle |
| Sequence | None |
| Duration | 2 seconds or more |
| DTC Type | Two drive cycles, MIL ON |
| OBD Status | PASSED/FAILED/NOT COMPLETED (STILL TESTING) |
ENABLE CONDITIONS CHART
| Condition | Minimum | Maximum | |
|---|---|---|---|
| Engine coolant temperature | 156°F (69°C) | - | |
| Engine speed | 1,300 rpm | 7,600 rpm | |
| Vehicle speed | 15 mph (24 km/h) | - | |
| Throttle position | 1,000 rpm | 11.2° | - |
| 4,000 rpm | 22.5° | ||
| No active DTCs | P0107, P0108, P0117, P0118, P0122, P0123, P0171, P0172, P0222, P0223, P0300, P0301, P0302, P0303, P0304, P0506, P0507, P1109, P1129, P2101, P2108, P2118, P2122, P2123, P2127, P2128, P2135, P2138, P2176, P2227, P2228, P2229, P2279, P2646, P2647, P2648, P2649, U0107 | ||