P0507 Honda Accord: Idle Control System RPM Higher Than Expected

Honda Accord P0507 Idle Control Diagnosis

Quick Answer: What is P0507?

On a Honda Accord, the P0507 code means the engine's idle speed is significantly higher than the target RPM set by the computer. Usually, an Accord should idle around 650-750 RPM; if it stays above 900-1000 RPM while stopped, the ECM triggers this code. The most common cause is a dirty throttle body or a vacuum leak.

Note: If you recently cleaned your throttle body or disconnected the battery, your Accord might just need an Idle Relearn Procedure to fix this code without replacing any parts.

Common Symptoms

High Idle: The engine revs high while in Park or Neutral.
Surging: The RPM "hunts" or bounces up and down.
Hard Shifting: The automatic transmission may jerk when shifting into Drive or Reverse.
Check Engine Light: On with code P0507.

Most Likely Causes

Dirty Throttle Body (70%): Carbon buildup prevents the butterfly valve from closing fully.
Vacuum Leak (20%): Unmetered air entering through cracked intake boots or gaskets.
Faulty PCV Valve: A stuck open PCV valve acts like a large vacuum leak.
Power Steering Pressure Sensor: A shorted sensor can trick the ECM into raising the idle.

Detailed Repair Cost & Labor Analysis

Estimates for Honda Accord (2.4L and 3.5L engines) in the US market:

Component / Task	Part Cost	Labor Time	Difficulty	Total (Est.)
Throttle Body Cleaning	$15 (Spray)	1.0 hr	Easy (DIY)	$95 - $135
Intake Manifold Gasket	$25 - $40	2.0 hrs	Moderate	$180 - $260
PCV Valve Replacement	$20 - $35	0.5 hr	Easy	$70 - $110

How to Fix P0507 on a Honda Accord

Step 1: Inspect the Air Intake Hose

On Honda Accords, the large rubber hose between the air filter box and the throttle body often cracks in the "accordion" sections. Even a small crack will let in extra air, raising the idle. Tape it temporarily to see if the RPM drops; if it does, replace the hose.

Step 2: Clean the Throttle Body

Remove the intake hose and use Throttle Body Cleaner on a microfiber cloth to wipe away the black carbon ring around the butterfly valve. Warning: Do not spray directly into the motor assembly; wipe it manually and do not force the valve open aggressively on electronic models.

Step 3: The Idle Relearn Procedure

If the idle is still high after cleaning, you must perform a relearn:
1. Make sure all electrical loads (A/C, lights, radio) are OFF.
2. Start the engine and hold it at 3,000 RPM until the cooling fan comes on.
3. Let it idle for 5 to 10 minutes with the throttle fully closed.