P0505 OBD-II Trouble Code: Idle Control System Malfunction

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0505 code

P0505 is a diagnostic trouble code (DTC) for "Idle Control System Malfunction". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0505 DIAGNOSTIC Get a fair and transparent estimate upfront

P0505 code definition

Idle Control System Malfunction

What the P0505 code means

P0505 is an OBD-II generic code that the engine control module (ECM) determined the engine idle control system is not managing the idle to stay in specification. The idle is too high or goes too low.

What causes the P0505 code?

  • The idle air control (IAC) valve is carboned up and sticks or has limited control due to the carbon build up.

  • The IAC passages are clogged or restricted with dirt, debris or carbon build up.

  • The engine has a vacuum leak in the intake system after the throttle body that the ECM cannot control with the IAC.

What are the symptoms of the P0505 code?

  • The Check Engine Light will be illuminated and the code is set in ECM memory.
  • The engine idle may be lower or higher than specifications.
  • The engine may idle rough if it has a vacuum leak.
  • The engine may stall when coming to a stop.
  • The engine may idle too high at times.

How does a mechanic diagnose the P0505 code?

  • Scans codes and documents the code in the ECM, clears and verifies the code

  • Monitors the engine idle to see if it stays within specifications in and out of gear and on road test

  • Checks the engine for vacuum leaks

  • Checks the engine for carbon build up on throttle plates and IAC valve inlet

  • Disconnects the IAC to see if the engine base idle is within specifications

  • Removes the IAC and check for blockage of passages

Common mistakes when diagnosing the P0505 code

  • Not verifying that the engine does not have a vacuum leak before replacing the IAC
  • Not removing excessive carbon in the IAC passages if replacing the IAC valve

How serious is the P0505 code?

  • Code P0505 is an indication the IAC is not working correct and it can cause the engine to idle too low or high and the engine may stall when coming to a stop.

  • The Check Engine Light being on causes the vehicle to fail emission testing.

  • The code may be from the engine has a vacuum leak and this can cause the engine to run rough and have poor fuel mileage.

What repairs can fix the P0505 code?

  • Replacing the IAC valve and cleaning the throttle body and passages
  • Removing carbon from throttle body and IAC passages and clean IAC
  • Repairing a vacuum leak in the engine intake manifold vacuum system or gaskets

Additional comments for consideration regarding the P0505 code

Code P0505 is for erratic idle and lack of idle control. The most common problem is a vacuum line to one of the intake or throttle body ports.

Need help with a P0505 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
P0505
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0505 code.

SCHEDULE P0505 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,361

Rating Summary
4,946
200
50
30
135
4,946
200
50
30
135

William

16 years of experience
64 reviews
William
16 years of experience
Jeep Grand Cherokee - Check Engine Light is on - Denver, Colorado
Couldn’t be happier with my experience with William. Will happily recommend him to everyone and will definitely be using him again. Fantastic service.

Andrian

31 years of experience
112 reviews
Andrian
31 years of experience
BMW 525i - Check Engine Light is on - Fort Lauderdale, Florida
Highly recommend Adrian for all automotive services. Very professional and extremely knowledgeable about everything related to our car. He explained everything so we knew exactly what was needed and went above and beyond to make the process easy. I would never use another person to work on our cars. EXCELLENT OVERALL!!

Brian

22 years of experience
335 reviews
Brian
22 years of experience
Chevrolet Colorado - Check Engine Light is on - Orange Park, Florida
Brian is a very experienced mechanic. Billing not so sharp. Wrong time (corona-19).to be stiff with adding up, Informing the older customers what to expect? Very sorry to say goodbye to a great mechanic!

Scott

35 years of experience
665 reviews
Scott
35 years of experience
Dodge Grand Caravan - Check Engine Light is on - Phoenix, Arizona
This is the second time I have used his service. All I can say. if he can find my mistakes, he can fix anything. Thanks once again.


Related questions

Code p0505

For the P0505 code, you should make sure that the PCV valve is clean or you should have the valve replaced. The throttle idle valve should be removed and throttle plates and IAC passages cleaned out. Make sure there is...

My truck runs till it gets warm then acts like it has no power.

Hi there. It seems that your vehicle has multiple malfunctions that are happening at the same time. The idle air control valve has a fault, evaporative emission system has a large leak, the gear ratio is incorrect, and knock sensor...

Failed emissions after P0505 code... Considering options

The mechanic that checked your vehicle is giving you a possible fix by cleaning the throttle body of built up carbon. This may help with the idle and P0505 code, and for passing the emissions test. The throttle body is...

More related articles

P0226 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch C Circuit Range/Performance Problem
P0226 P0226 code definition Throttle/Pedal Position Sensor/Switch C Circuit Range/Performance Problem What the P0226 code means P0226 is a generic OBD-II code which indicates that the throttle/pedal position sensor/switch C circuit has a range or performance problem causing the sensor...
P0150 OBD-II Trouble Code: O2 Sensor Circuit Malfunction (Bank 2, Sensor 1)
P0150 P0150 code definition O2 Sensor Circuit Malfunction (Bank 2 Sensor 1) What the P0150 code means P0150 is the OBD-II generic code indicating the O2 sensor 1 for bank 2 fails to meet the minimum or maximum voltage limits...
P2425 OBD-II Trouble Code: Exhaust Gas Recirculation Cooling Valve Control Circuit Open
P2425 P2425 code definition Exhaust Gas Recirculation Cooling Valve Control Circuit Open What the P2425 code means P2425 is an OBD-II generic code that the engine control module (ECM) detected the engine exhaust gas recirculation cooling bypass valve (EGRCBV) control...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com