AutoCodes – Generic – P1688

P1688 Code - Internal Fuel Injection Pump Controller Failure

Quick Answer

Fuel Pump Control Module (FPCM) is monitored with ignition on engine off, and with the engine running. Common causes include Good Trip Counter Equals Zero, Faulty Fuel Pump Control Module (FPCM), Fuel Pump Control Module (FPCM) harness is open or shorted. 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: P1688 indicates Internal Fuel Injection Pump Controller Failure.
Common causes: Common causes include Good Trip Counter Equals Zero, Faulty Fuel Pump Control Module (FPCM), Fuel Pump Control Module (FPCM) harness is open or shorted.
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 24,874

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 Sep 09, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1688 Description

Fuel Pump Control Module (FPCM) is monitored with ignition on engine off, and with the engine running. The P1688 code may set if FPCM, Powertrain Control Module (PCM) memory, programming or hardware error is detected.

OBDII Code P1688 - Internal Fuel Injection Pump Controller Failure - AutoCodes.com — P1688 Code - Internal Fuel Injection Pump Controller Failure

What does this mean?

What are the Possible Causes of the DTC P1688?

Good Trip Counter Equals Zero
Faulty Fuel Pump Control Module (FPCM)
Fuel Pump Control Module (FPCM) harness is open or shorted
Fuel Pump Control Module (FPCM) circuit poor electrical connection

How to Fix the DTC P1688?

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 P1688 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 P1688 code?

Need more information on how to fix the P1688 code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Makes

P1688 Chrysler — Internal Fuel Injection Pump Controller Failure
P1688 Dodge — Internal Fuel Injection Pump Controller Failure
P1688 Jeep — Internal Fuel Injection Pump Controller Failure

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.