AutoCodes – Generic – P158C

P158C Code - Idle Air Control Actuator 1 Self-Test Fault

Quick Answer

The Engine Control Module (ECM) monitors the Idle Air Control Actuator 1. Common causes include Faulty Idle Air Control Actuator, Idle Air Control Actuator harness is open or shorted, Idle Air Control Actuator 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: P158C indicates Idle Air Control Actuator 1 Self-Test Fault.
Common causes: Common causes include Faulty Idle Air Control Actuator, Idle Air Control Actuator harness is open or shorted, Idle Air Control Actuator 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 1,155

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jan 01, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P158C Description

The Engine Control Module (ECM) monitors the Idle Air Control Actuator 1. The ECM sets the OBDII code when the Idle Air Control Actuator 1 is not to factory specifications.

OBDII Code P158C - Idle Air Control Actuator 1 Self-Test Fault - AutoCodes.com — P158C Code - Idle Air Control Actuator 1 Self-Test Fault

What does this mean?

What are the Possible Causes of the DTC P158C?

Faulty Idle Air Control Actuator
Idle Air Control Actuator harness is open or shorted
Idle Air Control Actuator circuit poor electrical connection

How to Fix the DTC P158C?

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 P158C 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.

Need more information about the P158C code?

Need more information on how to fix the P158C code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P158C code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P158C BMW — Idle Air Control Actuator 1 Self-Test Fault
P158C MINI — Idle Air Control Actuator 1 Self-Test Fault

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.

Frequently Asked Questions about P158C Code

1. What are the common symptoms of OBDII code P158C (Idle Air Control Actuator 1 Self-Test Fault)?

Symptoms may include rough idling, stalling, poor engine performance, and the illumination of the Check Engine Light.

2. What can cause OBDII code P158C to trigger?

Possible causes include a faulty idle air control actuator, wiring issues, a vacuum leak, or a problem with the electronic control module.

3. How can I diagnose the cause of OBDII code P158C?

Diagnosis typically involves using a scan tool to retrieve the code, checking the wiring and connections to the idle air control actuator, and testing the actuator itself for proper operation.

4. Can I still drive my vehicle with OBDII code P158C present?

It is not recommended to drive your vehicle with this code present, as it can lead to further engine damage and potential safety issues. It is best to address the issue promptly.

5. How should I repair OBDII code P158C?

Repair options may include replacing the idle air control actuator, repairing any damaged wiring or connections, fixing vacuum leaks, or reprogramming the electronic control module.

6. Are there any DIY tips for fixing OBDII code P158C?

While some basic checks like inspecting for loose connections or vacuum leaks can be done by DIY enthusiasts, it is recommended to consult a professional mechanic for a proper diagnosis and repair.

7. Can a dirty throttle body cause OBDII code P158C?

While a dirty throttle body can impact engine performance, it is not a direct cause of this specific fault code. However, it is good practice to keep the throttle body clean for optimal engine operation.

8. How long does it typically take to repair OBDII code P158C?

The repair time can vary depending on the exact cause of the fault. In some cases, it can be a relatively quick fix, while in others, it may take more time to diagnose and repair the issue.

9. Is it possible for OBDII code P158C to come back after being repaired?

If the root cause of the issue is not properly addressed during the repair, there is a possibility for the code to return. It is important to ensure that all related components are thoroughly inspected and repaired.

10. Can OBDII code P158C affect fuel efficiency?

Yes, this fault code can impact fuel efficiency as it can lead to improper air-fuel mixture ratios and engine performance, causing the vehicle to consume more fuel.