P1128 ISUZU Possible Causes
- Engine mechanical condition
- Faulty Manifold Absolute Pressure (MAP) sensor
- Manifold Absolute Pressure (MAP) sensor harness is open or shorted
- Poor electrical connection in the Manifold Absolute Pressure (MAP) sensor circuit
How to Fix ISUZU Code P1128?
Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Check Engine Light on (or Service Engine Soon warning light)
P1128 ISUZU Meaning
The Manifold Absolute Pressure (MAP) sensor detects the intake manifold absolute pressure (vacuum) and converts it into electrical signals. The MAP sensor outputs a low signal voltage at high vacuum (idle) and a high signal voltage at low vacuum (wide open throttle).
The Engine Control Module (ECM) compares a predetermined MAP value for a given throttle position and intake manifold absolute pressure to the MAP sensor output voltage value.
If the MAP sensor delivers a voltage lower than expected, the ECM detects a malfunction and stores a DTC.