AutoCodes – Cadillac – P0628 Cadillac

P0628 Cadillac Code - Fuel Pump Speed Output Circuit Low Voltage

Quick Answer

The Engine Control Module (ECM) supplies voltage to the fuel pump driver control module for 30 s when the ignition is on and continuously when the engine is running. Common causes include Faulty Fuel Pump Driver Control Module, Fuel Pump Driver Control Module harness is open or shorted, Fuel Pump Driver Control Module 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
P0628 Cadillac indicates Fuel Pump Speed Output Circuit Low Voltage.
Common causes
Common causes include Faulty Fuel Pump Driver Control Module, Fuel Pump Driver Control Module harness is open or shorted, Fuel Pump Driver Control Module 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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 1,368
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jul 15, 2022
πŸ’¬ Need more help? Ask Coddy for instant answers β€” it's free!

Code P0628 Cadillac Description

The Engine Control Module (ECM) supplies voltage to the fuel pump driver control module for 30 s when the ignition is on and continuously when the engine is running. While this voltage is being received, a serial data signal containing the desired fuel pump speed is also received from the ECM. After the voltage and data have been received the fuel pump driver control module actuates the brushless fuel pump by means of a high power three phase signal. The Diagnostic Trouble Code (DTC) will be set when the Fuel Pump Speed Output Circuit is short to ground for greater than 2 s.
OBDII Code P0628 Cadillac - Fuel Pump Speed Output Circuit Low Voltage - AutoCodes.com
P0628 Cadillac Code - Fuel Pump Speed Output Circuit Low Voltage

What are the Possible Causes of the DTC P0628 Cadillac?

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

How to Fix the DTC P0628 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 P0628 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.

Need more information about the P0628 Cadillac code?

Need more information on how to fix the P0628 Cadillac code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0628 Cadillac code diagnosed by a professional: Find a repair shop in your area

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 P0628 Cadillac Code

1. What does the OBDII code P0628 mean for a Cadillac?

Code P0628 indicates a Fuel Pump Speed Output Circuit Low Voltage, meaning the ECM is detecting a low voltage condition in the fuel pump control circuit.

2. What are the common symptoms of code P0628 in a Cadillac?

Symptoms may include difficulty starting the engine, reduced fuel efficiency, engine stalling, or a complete failure to start.

3. What causes code P0628 to appear in a Cadillac?

Common causes include a faulty fuel pump relay, damaged wiring or connectors in the fuel pump circuit, a failing fuel pump, or a malfunctioning ECM.

4. How do you diagnose code P0628 on a Cadillac?

Diagnosis typically involves inspecting the fuel pump relay, checking wiring and connectors for damage or corrosion, and testing the fuel pump's voltage and resistance.

5. Can a faulty fuel pump trigger code P0628 in a Cadillac?

Yes, a failing or damaged fuel pump can cause low voltage in the circuit, leading to the P0628 code.

6. Is it safe to drive a Cadillac with code P0628?

Driving with code P0628 is not recommended as it can lead to engine stalling or failure to start, potentially leaving you stranded.

7. How can I fix code P0628 on a Cadillac?

Repairs may include replacing the fuel pump relay, repairing or replacing damaged wiring, cleaning corroded connectors, or replacing the fuel pump.

8. Can the ECM cause code P0628 on a Cadillac?

Yes, a malfunctioning ECM can incorrectly detect or cause low voltage in the fuel pump circuit, leading to the P0628 code.

9. How much does it cost to repair code P0628 on a Cadillac?

Repair costs vary depending on the issue but can range from $100 for wiring repairs to over $500 if the fuel pump needs replacement.

10. Will clearing the code P0628 solve the issue in a Cadillac?

Clearing the code may temporarily remove it, but the underlying problem must be addressed to prevent the code from returning.

Discuss the causes and fixes for P0628 Cadillac OBDII Code

  • 07 Cadillac sts 3.6 crank but don't start,was starting fine.I turned off to run in a place and tried to restart too leave,the crank no start beganed.Since I replaced the fuel pump,crank sensor and purge valve but still crank no start.the p0628 code is al I have to go on.

  • Unfortunately, I haven't had that problem before, but I searched a national database of repairs for the same model and year. A couple of technicians had the same code fixed the problem by cleaning the throttle body. If the problem persists, then you should replace the fuel pump relay.

  • will the engine not crank when code p0628 is activated

  • If there is an issue with the Fuel Pump Module, Fuel Pump, or Relay, the engine will attempt to crank but will not successfully start.

AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play