P1128 HONDA Possible Causes
- Mechanical condition of the engine
- Faulty Manifold Absolute Pressure (MAP) sensor
- Manifold Absolute Pressure (MAP) sensor harness is open or short-circuited
- Poor electrical connection in the Manifold Absolute Pressure (MAP) sensor circuit
How to Fix P1128 HONDA Code?
Start by checking the “possible causes” listed above. Visually inspect the corresponding cable harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Engine light on (or engine warning light soon to come on)
P1128 HONDA Meaning
The Manifold Absolute Pressure (MAP) sensor detects the absolute pressure of the manifold (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 (throttle wide open).
The Engine Control Module (ECM) compares a predetermined MAP value for a given throttle position and manifold absolute pressure to the output voltage value of the MAP sensor.
If the MAP sensor delivers a voltage lower than expected, the ECM detects a malfunction and stores a DTC.