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P1645 Cadillac 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 Cadillac 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 12,697

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
FAQs
Comments
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Code P1645 Cadillac 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 Cadillac - Evaporative Emission Purge Solenoid Output Circuit - AutoCodes.com — P1645 Cadillac Code - Evaporative Emission Purge Solenoid Output Circuit

What does this mean?

What are the Possible Causes of the DTC P1645 Cadillac?

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 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 P1645 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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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 P1645 Cadillac Code

1. What does the OBDII code P1645 mean for a Cadillac?

P1645 indicates an issue with the evaporative emission purge solenoid output circuit, which is responsible for controlling the flow of fuel vapors from the charcoal canister to the engine.

2. What are the common symptoms of code P1645 on a Cadillac?

Symptoms may include a check engine light, poor fuel efficiency, difficulty starting the vehicle, rough idle, and increased emissions.

3. What causes code P1645 on a Cadillac?

Common causes include a faulty purge solenoid, damaged wiring or connectors in the circuit, a blown fuse, or issues with the vehicle’s PCM (Powertrain Control Module).

4. Can code P1645 affect fuel economy?

Yes, a malfunctioning purge solenoid can lead to reduced fuel efficiency due to improper fuel vapor management.

5. How can I diagnose code P1645 on my Cadillac?

Diagnosis involves inspecting the purge solenoid, checking wiring and connectors for damage, testing the circuit for continuity, and verifying proper operation of the PCM.

6. Is it safe to drive my Cadillac with code P1645?

While the car may still be drivable, ignoring this code can lead to increased emissions, poor engine performance, and potential damage to other components.

7. How do I fix code P1645 on a Cadillac?

Repairs may include replacing the purge solenoid, repairing or replacing damaged wiring or connectors, or reprogramming or replacing the PCM if necessary.

8. Can a faulty gas cap cause code P1645?

A faulty gas cap is unlikely to directly cause P1645, but it can lead to other evaporative emission system issues. Always ensure the cap is properly sealed.

9. How much does it cost to fix code P1645 on a Cadillac?

Repair costs vary depending on the issue but typically range from $100 to $300, including parts and labor.

10. Do I need a professional to fix code P1645 on my Cadillac?

If you're comfortable with basic automotive repairs, you can attempt to replace the purge solenoid or check wiring yourself. However, complex diagnostics or PCM issues may require professional assistance.