AutoCodes – Cadillac – P15A1 Cadillac

P15A1 Cadillac 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 Cadillac 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 3,110

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

What does this mean?

What are the Possible Causes of the DTC P15A1 Cadillac?

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 Cadillac?

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 Cadillac 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.

Frequently Asked Questions about P15A1 Cadillac Code

1. What are the common symptoms of OBDII code P15A1 in a Cadillac related to Fuel Economy Mode Switch Performance?

The common symptoms include poor fuel economy, reduced engine performance, and the illumination of the check engine light.

2. What are the possible causes of OBDII code P15A1 in a Cadillac?

Possible causes include a faulty fuel economy mode switch, wiring issues, a malfunctioning PCM (powertrain control module), or software-related problems.

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

Diagnosing the issue may involve checking the fuel economy mode switch for proper operation, inspecting the wiring for any damage, and using a diagnostic scanner to read the code and monitor relevant data.

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

It is generally not recommended to continue driving with this code present, as it can lead to decreased fuel efficiency and potential long-term engine issues.

5. How can I repair OBDII code P15A1 related to Fuel Economy Mode Switch Performance in my Cadillac?

Repairing this code may involve replacing the faulty fuel economy mode switch, repairing any damaged wiring, or reprogramming the PCM with updated software.

6. Is it possible to reset OBDII code P15A1 in a Cadillac without fixing the underlying issue?

While you can clear the code with a diagnostic scanner, it is crucial to address the root cause to prevent the issue from recurring.

7. Can a DIY enthusiast fix OBDII code P15A1 in a Cadillac?

Depending on their skill level and access to tools, a DIY enthusiast may be able to address this issue by following repair guides and utilizing diagnostic equipment.

8. How much does it cost to repair OBDII code P15A1 in a Cadillac at a professional auto repair shop?

The cost of repair can vary depending on the specific cause of the issue, but it may range from a few hundred to over a thousand dollars, including parts and labor.

9. Are there any preventive measures to avoid OBDII code P15A1 in a Cadillac?

Regular maintenance, such as checking and servicing the fuel economy mode switch, can help prevent issues that may trigger this OBDII code.

10. How long does it typically take to repair OBDII code P15A1 related to Fuel Economy Mode Switch Performance in a Cadillac?

The repair time can vary based on the complexity of the issue and the availability of parts, but it may take a few hours to a full day for a professional mechanic to diagnose and fix the problem.