Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer has detected a problem with the electrical circuit that controls a secondary fuel pump. It's like a light switch being stuck in the 'on' position, which can cause issues with how the car gets fuel.
The P2634 code is triggered when the powertrain control module (PCM) detects a high voltage condition in the control circuit of the secondary fuel pump.
The secondary fuel pump, often referred to as Fuel Pump B, is responsible for supplying fuel to the engine. The PCM monitors the voltage in the control circuit of this pump. If the voltage is higher than the expected range, the PCM sets the P2634 code. This could result from a short to voltage or a faulty fuel pump relay.
• Check Engine Light is on
• Engine may not start
• Poor fuel efficiency
• Faulty fuel pump relay
• Short to voltage in the control circuit
• Defective secondary fuel pump
PCM: Powertrain Control Module
OBD-II: On-Board Diagnostics II
• Use an OBD-II scanner to confirm the code.
• Inspect the fuel pump relay and wiring for damage.
• Test the voltage in the fuel pump control circuit.
• Replace the faulty fuel pump relay.
• Repair or replace damaged wiring.
• Replace the secondary fuel pump if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect and maintain fuel system components.
• Ensure proper electrical connections.
• Use quality fuel to prevent clogging.
Sensor Issue
• Have the vehicle inspected by a professional if the Check Engine Light is on.
• Do not ignore the issue as it may lead to further damage.
Check with the vehicle manufacturer for specific warranty coverage related to fuel system components.
This code has been reported in vehicles with high mileage and those with a history of electrical issues.
Moderate – It is recommended to address this issue soon to avoid potential engine performance problems.
Driving with a malfunctioning fuel pump can lead to engine stalling, which is a safety hazard.
• Engine running
• Fuel system under load
The secondary fuel pump is typically located in or near the fuel tank.
Q: Can I drive with a P2634 code?
A: It's not recommended to drive for long periods with this code as it can lead to engine performance issues.
Q: How do I reset the Check Engine Light after fixing the issue?
A: Use an OBD-II scanner to clear the code after repairs are completed.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.