A diagnostic trouble code (DTC) is a signal your car sends to tell you something is wrong with its engine. Code readers that can read OBD-II codes allow you to read engine codes, commonly known as DTCs.
An engine code P0505 indicates an improperly functioning idle control system or idle air control valve. You should inspect your engine immediately if your vehicle is stalling or developing other problems.
Your car will behave incorrectly when you have a Honda P0505 OBDII trouble code. When your Honda’s idle air controller malfunctions, you’ll experience fluctuating idle, inconsistent throttle, and other symptoms.
This can be quickly and easily diagnosed by your mechanic since they should already have access to a code reader and the tools required to fix this problem.
P0505 Honda Code Definition: Idle Control System Malfunction
When an engine code P0505 appears, the idle control system or idle air control valve (IAC) on/near the throttle body is malfunctioning. Controlling the volume of air allowed into your engine while it idles is critical for maintaining the throttle speed.
Thus, the actual idle speed differs from the target idle speed. The idle speed of most cars is between 650 and 750 rpm. Older automobiles commonly have idle air control valves (IACs) near or on the throttle bodies. Measurement of air flowing through the throttle plate’s throat is the IAC’s job in maintaining idle speed.
When the car is idling, the throttle plate closes, reducing airflow to the engine. In contrast, the engine requires air to run. A bypass air channel is opened by the idle control system when the PCM commands it to do so. Air can still flow around and into the engine even if the throttle plate is closed.
In the idle control system, the bypass air channel size can be adjusted to regulate how much air the idling engine receives. It is possible to increase or decrease idle speeds by adjusting airflow.
Common Symptoms Of The Honda P0505 Engine Code
Similar to other automotive parts, the idle air control system wears and strains over time. When this component malfunctions, the engine’s idle speed may be adversely affected, resulting in P0505 codes.
When the IAC valve does not operate properly, the P0505 engine code will be set. The check engine light will turn on as the first sign. You should also keep an eye out for the following:
- Stalling of the vehicle
- An erratic or rough idle
- There is a problem starting the engine
- The engine can idle too high at times.
- The engine can die when coming to a stop.
- The engine can idle rough if there is a vacuum leak
- Depending on the engine, the idle speed may be higher or lower than recommended.
- An ECM code will be stored in the memory of the ECM, causing the Check Engine Light to come on.
What Could Cause The P0505 Honda Engine Code?
P0505 DTCs occur when the parts that control airflow in an idling engine malfunction. In most cases, the culprit is an idle air control valve that is worn or damaged.
Idle control maintains the engine’s throttle at its optimal level while the engine is idle. A throttle body-mounted idle air control valve opens or closes to accomplish this.
If too much air is in the engine, it will have to work harder than it should. The engine will stall if there is not enough air. P0505 engine codes are often caused by the idle air control valve, but it is not the only possible culprit. DTC P0505 can also be caused by the following:
- The powertrain control module (PCM) is malfunctioning
- The IAC circuit is not electrically connected
- The IAC harness is open or shorted
- There is a buildup of dirt, debris, or carbon in the IAC passages that blocks or narrows them.
- The engine’s intake system has a vacuum leak after the throttle body that the ECM cannot fix.
- It is difficult to control the idle air control (IAC) valve due to Carbon modification.
P0505 Code Diagnosis: How Does A Mechanic Do It?
An idle air control valve problem or a vacuum leak is usually the cause of P0505. Putting in a new idle air control valve may seem like a good idea, but the first thing you should do is check for a vacuum leak. Here are some things that a mechanic will do. You can also follow this checklist.
- Replacement of the IAC valve should involve cleaning the passages of excess carbon.
- Before replacing the IAC, make sure there is no suction leak in the engine.
- Several common pitfalls can be encountered when diagnosing the P0505 code.
- IACs should be removed and inspected in passageways.
- The IAC should be disconnected to test the engine’s idle base.
- Carbon buildup on tread plates and IAC valve inlets needs to be checked.
- Check the engine for vacuum leaks.
- Check the idle of the engine during a driving test to ensure it stays within specifications
- Clear and verify the code in the ECM after scanning and documenting it.
Is It Possible To Fix The P0505 Honda Engine Code Myself?
There are many causes of DTC P0505, making it difficult for the average person to fix it on their own. Taking your car to a professional is a smart idea if you are not confident about your car skills.
- Checking the exhaust camshaft position actuator solenoid
- Following these steps will help you determine whether you can do a quick fix on your car yourself if you have the necessary skills:
- Make sure the idle air control valve’s (IAC) wiring harness and connectors are in good working order
- The IAC should be checked for damage
- Make sure the pins of the connector are not broken, bent, pushed out, or corroded
- The intake manifold and gaskets may need to be inspected and possibly repaired for a vacuum leak.
- Clean throttle body passages and install a new IAC valve.
After following these steps, if the DTC still appears, you need professional help.
If My Car Has A Trouble Code P0505 And A CEL Light On, Can I Drive It?
An immediate fix is needed for error code P0505. However, if the engine stalls or stutters in a way that makes driving difficult, you can still drive your car even if the P0505 code is displayed.
You may encounter errors or not be able to control the idle speed. It is most common for a vacuum line to leak at one of the intake or throttle body ports.
Checking for leaks in the engine before replacing the IAC is a good practice. The passages of the IAC valve should not contain too much carbon if the valve is being replaced.
P0505 Honda Engine Code: How Serious Is It?
For your vehicle to function properly, you need proper airflow into the engine. P0505 engine codes should be investigated by your mechanic as soon as possible if you discover them or have symptoms of them.
If an engine doesn’t get enough air, it will either work too hard or stall. A stranded vehicle or engine parts that are worn out over time could be the result in the short term. Avoid having to tow your vehicle or replace engine parts prematurely by fixing a P0505 engine code as soon as possible.
It is possible that the IAC malfunctions, causing the engine to idle low or high or to stall when the vehicle is stopped. Having the Check Engine Light on will result in a failed emissions test. An engine with a vacuum leak may also run rough and be less fuel efficient.
How Much Will It Cost To Fix Code P0505 Honda?
You may have to pay $70-$400+ to replace the idle air control valve if your car’s engine code is caused by it. An hour should be enough for a mechanic to accurately diagnose a P0505 DTC.
Labor costs vary depending on the shop, but generally speaking, you can expect a bill between $75 and $150. The cost of labor and parts for fixing a P0505 engine code depends on your location and your car’s make and model.
Expect to pay between $145 and $550. It may be more expensive to repair a computer if the code source cannot be found or if other parts need to be replaced.
The Bottom Line
An engine code P0505 indicates an engine that is difficult to start, runs rough, or idles irregularly. It is also possible for an engine to stall at a stoplight after reaching temperature (for example, after it has gotten warm).
Honda Civic and Honda Accord commonly experience Code P0505 problems, which are usually remedied by adjusting the idle speed.
The Odyssey minivan and the Honda Pilot are other Honda models that can sometimes experience this problem.
Your Accord is suffering from P0505. Good luck diagnosing it. In most cases, it’s due to a vacuum leak or a malfunctioning idle air control valve.