AutoCodes – Cadillac – P2634 Cadillac

P2634 Cadillac Code - Fuel Transfer Pump Relay Control Circuit High Voltage

Quick Answer

The Engine Control Module (ECM) enables the secondary fuel pump relay when the primary fuel tank is below approximately 50 liters (13.2 gallons) and will run until the primary tank is filled to approximately 70 liters (18.5 gallons) or until the secondary tank is empty. Common causes include Faulty Secondary Fuel Pump Relay, Secondary Fuel Pump Relay harness is open or shorted, Secondary Fuel Pump Relay 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: P2634 Cadillac indicates Fuel Transfer Pump Relay Control Circuit High Voltage.
Common causes: Common causes include Faulty Secondary Fuel Pump Relay, Secondary Fuel Pump Relay harness is open or shorted, Secondary Fuel Pump Relay 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 381

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 Aug 01, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P2634 Cadillac Description

The Engine Control Module (ECM) enables the secondary fuel pump relay when the primary fuel tank is below approximately 50 liters (13.2 gallons) and will run until the primary tank is filled to approximately 70 liters (18.5 gallons) or until the secondary tank is empty. The ECM provides ignition positive voltage to the coil side of the fuel transfer pump relay. The ECM energizes the fuel transfer pump relay, which applies power to the fuel transfer pump.
The control module monitors the voltage on the fuel transfer pump relay control circuit. If the control module detects an incorrect voltage on the fuel transfer pump relay control circuit, a fuel transfer pump relay control Diagnostic Trouble Code (DTC) sets.

OBDII Code P2634 Cadillac - Fuel Transfer Pump Relay Control Circuit High Voltage - AutoCodes.com — P2634 Cadillac Code - Fuel Transfer Pump Relay Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P2634 Cadillac?

Faulty Secondary Fuel Pump Relay
Secondary Fuel Pump Relay harness is open or shorted
Secondary Fuel Pump Relay circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P2634 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 P2634 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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Need Help with the Code?

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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 P2634 Cadillac Code

1. What are the common symptoms of OBDII code P2634 in a Cadillac related to the Fuel Transfer Pump Relay Control Circuit High Voltage issue?

- Common symptoms include rough engine performance, stalling, poor fuel efficiency, and the illumination of the Check Engine Light.

2. What are the possible causes of OBDII code P2634 in a Cadillac triggering the Fuel Transfer Pump Relay Control Circuit High Voltage fault?

- Possible causes include a faulty fuel transfer pump relay, issues with the fuel transfer pump, wiring or electrical faults, or a problem with the engine control module.

3. How can I diagnose the OBDII code P2634 in a Cadillac indicating a Fuel Transfer Pump Relay Control Circuit High Voltage problem?

- Diagnosis typically involves using a scan tool to retrieve the trouble codes, inspecting the fuel transfer pump relay and related components, and testing the circuit for proper voltage and continuity.

4. Is it safe to continue driving my Cadillac with OBDII code P2634 indicating a Fuel Transfer Pump Relay Control Circuit High Voltage fault?

- It is not recommended to drive the vehicle with this code present, as it can lead to further damage to the fuel system and potentially cause unsafe driving conditions.

5. What are some repair tips for addressing OBDII code P2634 in a Cadillac related to the Fuel Transfer Pump Relay Control Circuit High Voltage issue?

- Repair tips may include checking and replacing the fuel transfer pump relay, inspecting and repairing any damaged wiring, ensuring proper connection of electrical components, and clearing the trouble codes.

6. Can a DIY enthusiast fix OBDII code P2634 in a Cadillac associated with the Fuel Transfer Pump Relay Control Circuit High Voltage problem?

- Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to address this issue by following repair guides and diagnostic procedures carefully.

7. How much does it typically cost to repair OBDII code P2634 in a Cadillac due to the Fuel Transfer Pump Relay Control Circuit High Voltage fault?

- Repair costs can vary depending on the root cause of the issue, but it may range from $100 to $500 or more, including parts and labor.

8. Will resetting the Check Engine Light resolve OBDII code P2634 in a Cadillac related to the Fuel Transfer Pump Relay Control Circuit High Voltage problem?

- Resetting the Check Engine Light without addressing the underlying cause will not fix the issue. It is essential to diagnose and repair the root cause of the fault code.

9. What steps should I take if OBDII code P2634 in a Cadillac persists even after repairs for the Fuel Transfer Pump Relay Control Circuit High Voltage concern?

- If the code persists after repairs, further diagnosis may be necessary to identify any underlying issues that were not initially addressed or to ensure proper repair of the initial problem.

10. Can severe weather conditions or driving off-road contribute to triggering OBDII code P2634 in a Cadillac indicating a Fuel Transfer Pump Relay Control Circuit High Voltage fault?

- Extreme weather conditions or off-road driving may expose the vehicle to additional stress, potentially leading to electrical or component failures that could trigger the P2634 code. Regular maintenance and inspections can help prevent such issues.