AutoCodes – Chevrolet – P159F Chevrolet

P159F Chevrolet Code - Fuel Economy Mode Switch Circuit Low Voltage

Quick Answer

The Engine Control Module (ECM) supplies 5 V reference voltage, through the 5 V reference voltage circuit, to the S87 fuel economy mode switch. Common causes include Faulty Fuel Economy Mode Switch, Fuel Economy Mode Switch harness is open or shorted, Fuel Economy Mode Switch 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: P159F Chevrolet indicates Fuel Economy Mode Switch Circuit Low Voltage.
Common causes: Common causes include Faulty Fuel Economy Mode Switch, Fuel Economy Mode Switch harness is open or shorted, Fuel Economy Mode Switch 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 11,371

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 02, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P159F Chevrolet Description

The Engine Control Module (ECM) supplies 5 V reference voltage, through the 5 V reference voltage circuit, to the S87 fuel economy mode switch. The 5 V reference voltage causes current to flow through a series of resistors in the switch to the switch ground circuit. The ECM monitors the reference voltage through a discrete fuel economy mode switch signal circuit. When the switch button is momentarily pressed, the switch contacts allow the 5 V reference voltage to by-pass one of the resistors. The ECM detects the resulting voltage drop as a fuel economy mode request and sends a GMLAN message to the Transmission Control Module (TCM) indicating the request. When the TCM receives the request, throttle progressions and transmission shift points are modified to optimize fuel efficiency. The Instrument Panel Cluster (IPC) also receives the fuel economy mode request message from the ECM and illuminates the fuel economy mode indicator lamp. The fuel economy mode switch must be pressed for between 0.094-1.5 s to activate the fuel economy mode.

OBDII Code P159F Chevrolet - Fuel Economy Mode Switch Circuit Low Voltage - AutoCodes.com — P159F Chevrolet Code - Fuel Economy Mode Switch Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P159F Chevrolet?

Faulty Fuel Economy Mode Switch
Fuel Economy Mode Switch harness is open or shorted
Fuel Economy Mode Switch circuit poor electrical connection

How to Fix the DTC P159F Chevrolet?

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 P159F Chevrolet 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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Need more information on how to fix the P159F Chevrolet code? Get Access to Factory Service Manuals

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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.

Frequently Asked Questions about P159F Chevrolet Code

1. What are the common symptoms of OBDII code P159F in a Chevrolet related to the Fuel Economy Mode Switch Circuit Low Voltage?

- Common symptoms include poor fuel economy, illuminated check engine light, and potential issues with the vehicle's performance.

2. What are the possible causes of the P159F code in a Chevrolet?

- The code P159F in a Chevrolet can be caused by a faulty fuel economy mode switch, damaged wiring or connectors in the circuit, or a malfunctioning PCM.

3. How can I diagnose the Fuel Economy Mode Switch Circuit issue causing the P159F code in my Chevrolet?

- To diagnose the issue, you can visually inspect the wiring and connectors for any damage, test the fuel economy mode switch for proper functionality, and use a scan tool to check the PCM for related faults.

4. Are there any repair tips for fixing the Fuel Economy Mode Switch Circuit Low Voltage issue in a Chevrolet?

- Repair tips include repairing or replacing damaged wiring and connectors, replacing the faulty fuel economy mode switch, and resetting the PCM after making any necessary repairs.

5. Can I drive my Chevrolet with the P159F code related to the Fuel Economy Mode Switch Circuit Low Voltage?

- It is not recommended to drive your Chevrolet with the P159F code present, as it can lead to poor fuel economy and potential performance issues. It is best to address the issue promptly.

6. How much does it typically cost to repair the Fuel Economy Mode Switch Circuit issue causing the P159F code in a Chevrolet?

- The cost of repairs can vary depending on the exact cause of the issue, but it may range from around $100 for basic repairs to a few hundred dollars for more complex repairs involving component replacement.

7. Can a DIY enthusiast fix the P159F code related to the Fuel Economy Mode Switch Circuit in a Chevrolet?

- Depending on your skill level and access to tools, a DIY enthusiast may be able to diagnose and repair the issue. However, it's recommended to have a professional mechanic handle more complex repairs.

8. How urgent is it to address the P159F code in a Chevrolet?

- While the vehicle may still be driveable with the P159F code, it's important to address the issue promptly to prevent further damage and ensure optimal fuel efficiency and performance.

9. Will resetting the PCM clear the P159F code related to the Fuel Economy Mode Switch Circuit in a Chevrolet?

- Resetting the PCM may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to return. It's crucial to diagnose and repair the root cause of the problem.

10. Can extreme weather conditions affect the triggering of the P159F code in a Chevrolet?

- Extreme weather conditions can potentially impact the circuitry and components related to the Fuel Economy Mode Switch, leading to the triggering of the P159F code. It's important to keep this in mind when diagnosing the issue.