AutoCodes – Lincoln – P1605 Lincoln

P1605 Lincoln Code - PCM Keep Alive Memory Test Error Conditions

Quick Answer

With the Key On Engine Off (KOEO) the Diagnostic Trouble Code (DTC) P1605 indicates Powertrain Control Module (PCM) has experienced power interrupt in the keep-alive power circuit. Common causes include Low battery charge, Faulty Powertrain Control Module (PCM), Powertrain Control Module 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: P1605 Lincoln indicates PCM Keep Alive Memory Test Error Conditions.
Common causes: Common causes include Low battery charge, Faulty Powertrain Control Module (PCM), Powertrain Control Module 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 727

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Sep 30, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1605 Lincoln Description

OBDII Code P1605 Lincoln - PCM Keep Alive Memory Test Error Conditions - AutoCodes.com — P1605 Lincoln Code - PCM Keep Alive Memory Test Error Conditions

What does this mean?

What are the Possible Causes of the DTC P1605 Lincoln?

Low battery charge
Faulty Powertrain Control Module (PCM)
Powertrain Control Module harness is open or shorted
Powertrain Control Module circuit poor electrical connection

How to Fix the DTC P1605 Lincoln?

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 P1605 Lincoln 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 P1605 Lincoln Code

1. What does the OBDII code P1605 mean on a Lincoln?

P1605 indicates a "PCM Keep Alive Memory Test Error," meaning the Powertrain Control Module (PCM) is unable to retain memory during key-off conditions.

2. What are common symptoms of the P1605 code on a Lincoln?

Symptoms may include difficulty starting the vehicle, erratic engine performance, unexpected stalling, or loss of adaptive memory settings like fuel trims or idle control.

3. What causes the P1605 code to appear on a Lincoln?

Common causes include a weak or failing vehicle battery, corroded or loose battery terminals, faulty PCM, or damaged wiring to the PCM.

4. Can a weak battery trigger the P1605 code?

Yes, a weak or failing battery is a common cause of the P1605 code, as the PCM requires a stable power supply to retain its memory.

5. How do you diagnose the P1605 code on a Lincoln?

Start by checking the battery voltage, inspecting battery terminals for corrosion or looseness, examining PCM wiring for damage, and scanning for additional trouble codes.

6. Can I drive my Lincoln with the P1605 code?

Itâ€™s possible, but not recommended. The code can lead to unpredictable engine performance, which may result in stalling or safety concerns.

7. How can I fix the P1605 code on my Lincoln?

Repair steps include replacing a weak battery, cleaning or tightening battery connections, inspecting and repairing PCM wiring, or replacing the PCM if itâ€™s confirmed faulty.

8. How much does it cost to repair the P1605 code on a Lincoln?

Costs vary depending on the issue. Battery replacement may cost $100-$300, while PCM replacement could range from $500 to $1,500, including programming.

9. Can a blown fuse cause the P1605 code on a Lincoln?

Yes, a blown keep-alive memory (KAM) fuse can disrupt the PCMâ€™s power supply, leading to this code.

10. Does the P1605 code require PCM replacement?

Not always. PCM replacement is only necessary if all other issues, like battery or wiring problems, have been ruled out and the PCM is confirmed to be faulty.