AutoCodes – Buick – P1645 Buick

P1645 Buick Code - Evaporative Emission Purge Solenoid Output Circuit

Quick Answer

The Powertrain Control Module (PCM) contains Output Driver Modules (ODM) that provides 7 switchable ground outputs for operating solenoids, relays, indicator lights, and other devices. Common causes include Faulty Evaporative Emission Vent Solenoid, Evaporative Emission Vent Solenoid harness is open or shorted, Evaporative Emission Vent Solenoid 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: P1645 Buick indicates Evaporative Emission Purge Solenoid Output Circuit.
Common causes: Common causes include Faulty Evaporative Emission Vent Solenoid, Evaporative Emission Vent Solenoid harness is open or shorted, Evaporative Emission Vent Solenoid 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 5,818

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 Feb 24, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1645 Buick Description

The Powertrain Control Module (PCM) contains Output Driver Modules (ODM) that provides 7 switchable ground outputs for operating solenoids, relays, indicator lights, and other devices. Each of these ground outputs has fault lines that feedback to the PCM microprocessor. When the output is off, the output driver should receive the 12 volts fed to the solenoid, relay, etc. When the output is on, it should receive zero volts, since it is grounding the output. If PCM sees zero volts when the output is off or 12 volts when the output is on, it sets a fault line low. The Diagnostic Trouble Code (DTC) is used to monitor the fault line of the EVAP control solenoid. With the engine runtime over 10 seconds, the PCM detects that the EVAP Solenoid Circuit line was low, conditions met for 2 seconds, and the DTC sets.

OBDII Code P1645 Buick - Evaporative Emission Purge Solenoid Output Circuit - AutoCodes.com — P1645 Buick Code - Evaporative Emission Purge Solenoid Output Circuit

What does this mean?

What are the Possible Causes of the DTC P1645 Buick?

Faulty Evaporative Emission Vent Solenoid
Evaporative Emission Vent Solenoid harness is open or shorted
Evaporative Emission Vent Solenoid circuit poor electrical connection

How to Fix the DTC P1645 Buick?

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 P1645 Buick 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.