Usually, P1519 means that there is a problem with the idle air control valve circuit (IAC) on Honda vehicles. This problem can be solved by simply replacing it. Your car needs an IAC if you want it to start and idle properly. It might be that a wire got shorted or something like that.
To ensure the wire is not shorted, I recommend tracking it down at the ECU harness and testing it there. If you need specific instructions or testing procedures, you should be able to get help from someone who has a shop manual.
As part of the idle regulation, the IAC lets air into the tract when the car is started. Without it, nothing gets into the tract.
P1519 Honda Definition: Idle Air Control Valve Circuit Malfunction
There are various engine conditions (coolant temperature, A/C operation, and other functions) that can affect the target idle speed stored in the Engine Control Module (ECM).
To control intake airflow, the ECM switches the Idle Air Control Valve (IACV) ON/OFF to maintain the target idle speed.
Moreover, the IACV is also the first idle valve that controls the engine speed based on the temperature of the engine coolant.
A malfunction occurs when duty cycle signals are not inputted into a circuit that checks return signals in the ECM, resulting in the P1519 code. As well, the check engine light will be on as the only symptom.
Common P1519 Failure Symptoms
- Start-up difficulties when cold
- Unstable idleness
- Cold temperatures cause low idle speeds
Possible Causes Of The Code P1519 Honda
- A poor electrical connection is present in the idle air control valve circuit.
- There is an open or shorted harness on the idle air control valve
- IACV (Idle Air Control Valve) failure
Diagnosis of Honda Code P1519 Idle Air Control Valve
It represents the code for a rotary air control valve, also known as an IAC or RACV. The valve is likely to have failed. However, it is highly unlikely to be a wiring or ECU problem.
Cleaning the IAC is not recommended by Honda as a method of repair. It is necessary to replace the IAC once it sets this code. The valve can be tested in a somewhat complicated manner to confirm that it is bad, but the procedure requires a lot of effort.
A primary goal of these tests is to eliminate any possibility of wiring or electronic control unit failure.
Can A Bad IAC Cause Idle Issues And Starting Issues After the Engine Is Warm?
There is no doubt that it can cause such problems. With IAC, you can modulate the throttle like you would with your foot. Of course, you can’t do this with your foot, but the IAC can. Depending on the input conditions detected by the ECU, the ECU can shift idle speeds as needed.
How To Fix The P1519 Honda Code?
The first thing you should do is check the list of “Possible Causes” above. Next, check the connectors and wiring harness associated with the wiring harness. Finally, make sure that the connector’s pins are not bent, broken, or corroded and that none of the components are damaged.
You need to ensure that the IAC valve is plugged in when you have P1519. An electrical failure is usually caused by wiring but can also be caused by a faulty electrical component.
Common Mistakes When Fixing
Your vehicle has a common head gasket that won’t set the P1519 code, and a faulty IACV won’t cause low compression either.
P1519 codes are usually caused by dirty/loose/corroded wiring plug connections at the IACV on Hondas. The intake manifold has this on the backside.
There could be a problem with the IACV itself, or there could be a shortage in the wiring harness. See if it comes back after clearing the codes, then recheck them.