AutoCodes – Generic – P15A1

P15A1 Code - Fuel Economy Mode Switch Performance

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: P15A1 indicates Fuel Economy Mode Switch Performance.
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 21,872

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 P15A1 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 P15A1 - Fuel Economy Mode Switch Performance - AutoCodes.com — P15A1 Code - Fuel Economy Mode Switch Performance

What does this mean?

What are the Possible Causes of the DTC P15A1?

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 P15A1?

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 P15A1 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 P15A1 code?

Need more information on how to fix the P15A1 code? Get Access to Factory Service Manuals

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Information for Specific Makes

P15A1 BMW — Engine Oil Pressure Mechanical Control Solenoid Sticking Activated
P15A1 Buick — Fuel Economy Mode Switch Performance
P15A1 Cadillac — Fuel Economy Mode Switch Performance
P15A1 Chevrolet — Fuel Economy Mode Switch Performance
P15A1 GMC — Fuel Economy Mode Switch Performance
P15A1 Honda — Motor Driver Module Temperature Signal Circuit High
P15A1 MINI — Engine Oil Pressure Mechanical Control Solenoid Sticking Activated

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 P15A1 Code

1. What are common symptoms of OBDII code P15A1, Fuel Economy Mode Switch Performance?

- Common symptoms include decreased fuel efficiency, rough idling, and potentially a check engine light.

2. What can cause the OBDII code P15A1 to trigger?

- The code P15A1 may be triggered by a faulty fuel economy mode switch, wiring issues, or a malfunction in the engine control module.

3. How can I diagnose the cause of the OBDII code P15A1?

- Diagnosing the code involves checking the fuel economy mode switch, inspecting the wiring for damage or loose connections, and performing a scan with an OBDII scanner.

4. Can I continue driving my vehicle with the OBDII code P15A1 present?

- It is generally not recommended to continue driving with the code present as it can lead to decreased fuel efficiency and potentially cause further damage to the engine.

5. How can I repair the OBDII code P15A1, Fuel Economy Mode Switch Performance?

- Repairing the code may involve replacing the fuel economy mode switch, repairing any damaged wiring, or resetting the engine control module.

6. Are there any DIY tips for fixing the OBDII code P15A1?

- DIY tips include checking for loose connections, inspecting the switch for any visible damage, and resetting the code with an OBDII scanner after making repairs.

7. Can a faulty fuel economy mode switch affect other systems in the vehicle?

- Yes, a faulty fuel economy mode switch can affect the vehicle's fuel management system, leading to poor fuel efficiency and potentially impacting engine performance.

8. How much does it typically cost to repair the OBDII code P15A1?

- Repair costs can vary depending on the extent of the issue, but replacing a fuel economy mode switch or repairing wiring may cost anywhere from $100 to $300 at a repair shop.

9. Will the OBDII code P15A1 reset on its own after repairs are made?

- In some cases, the code may reset on its own after repairs are made and the vehicle is driven for a certain amount of time. However, it is recommended to use an OBDII scanner to clear the code.

10. Is it possible for the OBDII code P15A1 to return after repairs?

- If the root cause of the issue is not properly addressed, the code P15A1 may return even after repairs. It is crucial to diagnose the problem accurately and ensure all necessary repairs are completed.