AutoCodes – Land Rover – P0505 Land Rover

P0505 Land Rover Code - Idle Control System Malfunction

Quick Answer

This system automatically controls engine idle speed to a specified level. Common causes include Faulty IACV-AAC valve, IACV-AAC valve harness is open or shorted, IACV-AAC valve circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0505 Land Rover indicates Idle Control System Malfunction.
Common causes: Common causes include Faulty IACV-AAC valve, IACV-AAC valve harness is open or shorted, IACV-AAC valve circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 2,309

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jan 18, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0505 Land Rover Description

This system automatically controls engine idle speed to a specified level. Idle speed is controlled through fine adjustment of the amount of air that bypasses the throttle valve via Idle Air Control Valve IACV) and Auxiliary Air Control AAC) Valve. The IACV-AAC valve changes the opening of the air bypass passage to control the amount of auxiliary air. This valve is actuated by a step motor built into the valve, which moves the valve in the axial direction in steps corresponding to the Engine Control Module (ECM) output signals.
One step of IACV-AAC valve movement causes the respective opening of the air bypass passage. (i.e. when the step advances, the opening is enlarged.) The opening of the valve is varied to allow for optimum control of the engine idling speed. The crankshaft position sensor (POS) detects the actual engine speed and sends a signal to the ECM. The ECM then controls the step position of the IACV-AAC valve so that engine speed coincides with the target value memorized in ECM. The target engine speed is the lowest speed at which the engine can operate steadily. The optimum value stored in the ECM is determined by taking into consideration various engine conditions, such as during warm-up, deceleration, and engine load (air conditioner, power steering, and cooling fan operation).

OBDII Code P0505 Land Rover - Idle Control System Malfunction - AutoCodes.com — P0505 Land Rover Code - Idle Control System Malfunction

What does this mean?

What are the Possible Causes of the DTC P0505 Land Rover?

Faulty IACV-AAC valve
IACV-AAC valve harness is open or shorted
IACV-AAC valve circuit poor electrical connection

How to Fix the DTC P0505 Land Rover?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0505 Land Rover code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.